Physical Activity and Health
in younger adults (Kohrt et al. 1991). The inter-
relationships of age, \i02max, and training status
are evident when the loss inVO,max with age is
compared for active and sedentary individuals
(Figure 3-5).
When the cardiorespiratory responses of an older
adult are coinpared with those of a young or middle-
aged adult at the same absolute submaximal rate of
work, stroke volume for an older person is generally
lower and heart rate is higher from the attempt to
maintain cardiac output. Because this attempt is
generally insufficient, the A-+0, difference must
increase to provide the same submaximal oxygen
uptake (Raven and Mitchell 1980; Thompson and
Dorsey 1986). Some researchers have shown, how-
ever, that cardiac output can be maintained at both
submaximal and maximal rates of work through a
higher stroke volume in older adults (Rodeheffer et
al. 1984).
The deterioration in physiological function nor-
mally associated with aging is, in fact, caused by a
combination of reduced physical activity and the
aging process itself. By maintaining an active
lifestyle, or by increasing levels of physical activ-
ity if previously sedentary, older persons can
maintain relatively high levels of cardiovascular
and metabolic function, including irO,max (Kohrt
et al. 199 1)) and of skeletal muscle function (Rogers
and Evans 1993). For example, Fiatarone and col-
leagues (1994) found an increase of 113 percent in
the strength of elderly men and women (mean age of
87.1 years) following a lo-week training program of
progressive resistance exercise. Cross-sectional thigh
muscle area was increased, as was stair-climbing
power, gait velocity, and level of spontaneous activ-
ity. Increasing endurance and strength in the elderly
contributes to their ability to live independently.
Differences by Sex
For the most part, women and men who participate
in exercise training have similar responses in car-
diovascular, respiratory, and metabolic function
(providing that size and activity level are normal-
iced). Relative increases in\jO,max are equivalent
Figure 3-5. Changes in 00, max with aging, comparing an active population and sedentary population (the
    figure also illustrates the expected increase in VO, max when a previously sedentary person begins
     an exercise program)
A-  Active adults
R&&on in
activity plus
weight gain
Sedentary adults
0 (              I              I              I
    20         30          40          50
                        Age (years)
Adapted, by permission, from Buskirk ER, Hodgson JL. Federation Proceedings 1987.
I              I              I
60          70          80
76

Physiologic Responses and Long-Term Adaptations to Exercise
for women and men (Kohrt et al. 1991; Mitchell et
al. 1992). Some evidence suggests that older women
accomplish this increase inVO,max mainly through
an increase in the AGO, difference, whereas younger
women and men have substantial increases in stroke
volume, which increases maximal cardiac output
(Spina et al. 1993). With resistance training, women
experience equivalent increases in strength (Rogers
and Evans 1993; Holloway and Baechle 1990),
although they gain less fat-free mass due to less
muscle hypertrophy.
  Several sex differences have been noted in the
acute response to exercise. At the same absolute
rate of exercise, women have a higher heart rate
response than men, primarily because of a lower
stroke volume. This lower stroke volume is a func-
tion of smaller heart size and smaller blood volume.
In addition, women have less potential to increase
the A-CO, difference because of lower hemoglobin
content. Those differences, in addition to greater
fat mass, result in a lower V02max in women, even
when normalized for size and level of training
(Lewis, Kamon, Hodgson 1986).
Conclusions
1. Physical activity has numerous beneficial physi-
ologic effects. Most widely appreciated are its
effects on the cardiovascular and musculo-
skeletal systems, but benefits on the functioning
of metabolic, endocrine, and immune systems
are also considerable.
2. Many of the beneficial effects of exercise train-
ing-from both endurance and resistance ac-
tivities-diminish within 2 weeks if physical
activity is substantially reduced, and effects
disappear within 2 to 8 months if physical
activity is not resumed.
3. People of all ages, both male and female, undergo
beneficial physiologic adaptations to physical
activity.
Research Needs
1. Explore individual variations in response to
exercise.
2.
3.
4.
5.
Better characterize mechanisms through which
the musculoskeletal system responds differen-
tially to endurance and resistance exercise.
Better characterize the mechanisms by which
physical activity reduces the risk of cardiovascular
disease, hypertension, and non-insulin-
dependent diabetes mellitus.
Determine the minimal and optimal amount of
exercise for disease prevention.
Better characterize beneficial activity profiles for
people with disabilities.
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80

             CHAPTER 4
THE EFFECTS OF PHYSICAL ACTIVITY ON
        HEALTH AND DISEASE
Contents
Introduction  .......................
Overall Mortality  ...................
Conclusions  .....................
Cardiovascular Diseases  ..............
. .
.
.
.....................................  85
.....................................  85
.....................................  87
.....................................  87
                                  . .
Cardiovascular Diseases Combined  ..........................................  87
Coronary Heart Disease  ...................................................  87
CVD Risk Factors in Children  ..............................................  91
Stroke   ................................................................ 102
HighBloodPressure  ......... . ............................................ 103
Biologic Plausibility  ...................................................... 110
Atherosclerosis  ........................................................ 110
Plasma Lipid/Lipoprotein Profile  .......................................... 111
BloodPressure   ........................................................ 111
lschemia  ............................................................. 111
Thrombosis  ........................................................... 112
Arrhythmia  ........................................................... 112
Conclusions  ............................................................ 112
Cancer  ................................................................... 112
Colorectal Cancer  ......................................................... 113
  Colon Cancer  ......................................................... 113
  RectalCancer  ......................................................... 116
Hormone-Dependent Cancers in Women  ..................................... 116
  BreastCancer  ......................................................... 117
  Other Hormone-Dependent Cancers in Women  .......................... 1 ... 120

Contents, continued
Cancers in Men . . . . . . . . .
Prostate Cancer . . . . . . .
Testicular Cancer . . . . .
Other Site-Specific Cancers
Biologic Plausibility . . . .
Conclusions . . _ . . . . . . . .
.......
.......
.......
.......
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
.............................. 121
.............................. 124
.............................. 124
..............................  124
.......................... . ... 124
Non-Insulin-Dependent Diabetes Melhtus  ...................................... 125
Physical Activity and NIDDM  .............................................. 125
Biologic Plausibility  ...................................................... 128
Conclusions  ............................................................ 129
Osteoarthritis  ............................................................. 129
Physical Activity in Persons with Arthritis ..................................... 129
Biologic Plausibility  ......................................................  130
Conclusions  ............... . ............................................ 130
Osteoporosis  .............................................................. 130
Biologic Plausibility  ...................................................... 13 1
Physical Activity and the Prevention of Fractures and Falling  .....................  132
Conclusions  ............................................................ 132
Obesity  .................................................................. 133
Physical Activity and Obesity  ............................................... 133
Biologic Plausibility  ...................................................... 134
Conclusions  ............................................................ 135
MentalHealth  ............................................................. 135
Physical Activity and Mental Health  ......................................... 136
Biologic Plausibility  ...................................................... 141
Conclusions  ............................................................. 141
Health-Related Quality of Life  ................................................ 141
Conclusions  ............................................................ 142

Contents, continued
Adverse Effects of Physical Activity  ............................................. 142
Types of Adverse Effects  .................................................... 142
  Musculoskeletal Injuries  .................................................. 142
  Metabolic Abnormalities .................................................. 143
  Hematologic and Body Organ Abnormalities  .................................. 143
  Hazards ........................................................ . .... ..14 3
  Infectious, Allergic, and Inflammatory Conditions  ............................. 143
  Cardiac Events  ......................................................... 143
Occurrence of Adverse Effects  ............................................... 144
Conclusions  ........................................................... ..14 4
Nature of the Activity/Health Relationship  ....................................... 144
Causality  ................................................................ 144
Population Burden of Sedentary Living  ........................................ 145
Dose  ................................................................... 146
Conclusions  ............................................................. 148
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .._..... 149
Conclusions  ............................................................. ..14 9
ResearchNeeds  ........................................................... 150
References . . . . . . . . .._........................._............................ 151

             CHAPTER 4
THE EFFECTS OF PHYSICAL ACTIVITV ON
        HEALTH AND DISEASE
Introduction
T his chapter examines the relationship of physi-
cal activity and cardiorespiratory fitness to a
variety of health problems. The primary focus is on
diseases and conditions for which sufficient data exist
to evaluate an association with physical activity, the
strength of such relationships, and their potential
biologic mechanisms. Because most of the research to
date has addressed the health effects of endurance-
type physical activity (involving repetitive use of
large muscle groups, such as in walking and bicy-
cling), this chapter focuses on that type of activity.
Unless otherwise specified, the term physical activity
should be understood to refer to endurance-type
physical activity. Less well studied are the health
effects of resistance-type physical activity (i.e., that
which develops muscular strength); when this type
of physical activity is discussed, it is specified as
such. Much of the research summarized is based on
studies having only white men as participants; it
remains to be clarified whether the relationships
described here are the same for women, racial and
ethnic minority groups, and people with disabilities.
Physical activity is difficult to measure directly.
Three types of physical activity measures have been
used in observational studies over the last 40 years.
Most studies have relied on self-reported level of
physical activity, as recalled by people prompted by
a questionnaire or interview. A more objectively
measured characteristic is cardiorespiratory fitness
(also referred to as cardiorespiratory endurance)
which is measured by aerobic power (see Chapter 2
for more information on measurement issues). Some
studies have relied on occupation to classify people
according to how likely they were to be physically
active at work.
Epidemiologic studies of physical activity and
health have compared the activity levels of people
who have or develop diseases and those who do not.
Cohort studies follow populations forward in time to
observe how physical activity habits affect disease
occurrence or death. In case-control studies, groups
of persons who have disease and separate groups of
people who do not have disease are asked to recall
their previous physical activity. Cross-sectional stud-
ies assess the association between physical activity
and disease at the same point in time. Clinical trials,
on the other hand, attempt to alter physical activity
patterns and then assess whether disease occurrence
is modified as a result.
Results from epidemiologic studies can be used
to estimate the relative magnitude or strength of an
association between physical activity and a health
outcome. Two such measures used in this chapter
are risk ratio (RR) and odds ratio (OR). For these
measures, an estimate of 1 .O indicates no association,
when the risk of disease is equivalent in the two
groups being compared. RR or OR estimates greater
than 1.0 indicate an increase in risk; those less than
1.0 indicate a decreased risk. Confidence intervals
(CI) reported with estimates of association indicate
the precision of the estimate, as well as its statistical
significance. When the CI range includes 1.0, the
effect is considered likely to have occurred by chance;
therefore the estimate of association is not consid-
ered statistically significantly different from the null
value of 1.0.
Overall Mortality
Persons with moderate to high levels of physical
activity or cardiorespiratory fitness have a lower
mortality rate than those with sedentary habits or

Physical Activity and Health
low cardiorespiratory fitness. For example, com-
pared with people who are most active, sedentary
people experience between a 1.2-fold to a 2-fold
increased risk of dying during the follow-up interval
(Slattery and Jacobs 1988; Slattery, Jacobs, Nichaman
1989; Leon and Connett 1991; Stender et al. 1993;
Sandvik et al. 1993; Chang-Claude and Frentzel-
Beyme 1993; Kaplan et al. 1987; Arraiz, Wigle, Mao
1992; Paffenbarger et al. 1993).
Associations are generally stronger for measured
cardiorespiratory fitness than for reported physical
activity (Blair, Kohl, Paffenbarger 1989). Blair, Kohl,
and Barlow (1993) showed that low levels of cardio-
respiratory fitness were strongly associated with
overall mortality for both women (RR = 5.35; 95%
CI, 2.44-11.73) and men (RR= 3.16; 95% CI, 1.92-
5.20). The association with physical inactivity was
weaker for men (RR = 1.70; 95% CI, 1.06-2.74), and
there was no association for women (RR = 0.95; 95%
CI, 0.54-1.70).
Though cardiorespiratory fitness may be the
better indicator of regular physical activity, the level
of reported physical activity has been associated with
reduced all-cause mortality. Paffenbarger, Lee, and
Leung (1994) evaluated several types of recalled
activity (walking, stair climbing, all sports, moderate-
level sports, and total energy expended in activity per
week) as predictors of all-cause mortality among
male Harvard alumni. Among these men, the relative
risk of death within the follow-up period was reduced
to 0.67 with walking 15 or more kilometers per week
(reference group, < 5 kilometers/week), to 0.75 with
climbing 55 or more flights of stairs per week (refer-
ence group, < 20 flights/week), to 0.63 with involve-
ment in moderate -sports (reference group, no
involvement), and to 0.47 with 3 or more hours of
moderate sports activities per week (reference group,
< 1 hour/week). Most importantly, there was a signifi-
cant trend of decreasing risk of death across increas-
ing categories of distance walked, flights of stairs
climbed, and degree of intensity of sports play.
Researchers have also examined age.-specific ef-
fects of different levels of physical activity on all-
cause mortality. Kaplan and colleagues (1987) have
shown that physical activity level has an effect on
death rates among both older and younger persons.
Data from a study of 9,484 Seventh-Day Adventist
men aged 30 years or older in 1958 who were
followed through 1985 indicated that both moderate
and intense levels of activity reduced overall risk of
death even late in life (Lindsted, Tonstad, Kuzma
1991). Both moderate and vigorous levels of activity
were equally protective at age 50 years. The protec-
tive effect of high levels of activity lasted only until
age 70, but the protective effect for moderate activity
lasted beyond age 80.
The studies cited thus far in this section assessed
physical activity or cardiorespiratory fitness at
baseline only and then followed up for mortality. A
stronger test for a causal relationship is to examine
the effect that changing from lower to higher levels
of physical activity or cardiorespiratory fitness has
on subsequent mortality. Two large studies provide
such evidence. Among middle-aged Harvard male
alumni who were sedentary in 1962 or 1966, those
who took up moderately intense sports activity dur-
ing the study's 11 years of follow-up had a 23 percent
lower death rate (RR= 0.77; 95% CI, 0.58-0.96) than
those who remained sedentary (Paffenbarger et al.
1993). (By comparison, men who quit smoking
during the interval had a 41 percent decrease in
death rate [RR = 0.59; 95% CI, 0.43-0.801.) Men
45-84 years of age who took up moderately intense
sports extended their longevity on average by 0.72
years; added years of life were observed in all
age groups, including men 75-84 years of age
(Paffenbarger et al. 1993).
  Similar reductions in death rates with increases
in cardiorespiratory fitness were reported for men in
the Aerobics Center Longitudinal Study. Blair and
colleagues (1995) reported a reduction in death rates
among healthy men (aged 20-82 years) who im-
proved their initially low levels of cardiorespiratory
fitness. The men performed two maximal exercise
tests an average of 4.8 years apart; follow-up for
mortality after the second test occurred an average of
4.7 years later. Among men in the bottom fifth of the
cardiorespiratory fitness distribution, those who
improved to at least a moderate fitness level had a 44
percent lower death rate than their peers who re-
mained in the bottom fifth (RR = 0.56; 95% CI, 0.41-
0.75). After multivariate adjustment, those who
became fit had a significant 64 percent reduction in
their relative mortality rate. In comparison, men
who stopped smoking reduced their adjusted RR by
about 50 percent.
86

Conclusions
The data reviewed here suggest that regular physical
activity and higher cardiorespiratory fitness decrease
overall mortality rates in a dose-response fashion.
Whereas most studies of physical activity and health
address specific diseases and health conditions, the
studies in this chapter provide more insight into the
biologic mechanisms by which mortality rate reduc-
tion occurs.
Cardiovascular Diseases
Despite a progressive decline since the late 196Os,
cardiovascular diseases (CVDs), including coronary
heart disease (CHD) andstroke, remain major causes
of death, disability, and health care expenditures in
the United States (NCHS 1994; Gillum 1994). In
1992, more than 860,000 deaths in the United States
were attributed to heart disease and stroke (DHHS
1994). High blood pressure, a major risk factor for
CVD, affects about 50 million Americans (National
Institutes of Health [NIH] 1993), including an esti-
mated 2.8 million children and adolescents 6-17
years of age (Task Force on Blood Pressure Control
in Children 1987). The prevalence of CVD increases
with age and is higher among African Americans than
whites. The majority of population-based research in
the area of physical activity and health has focused on
some aspect of CVD.
Cardiovascular Diseases Combined
Most of the reported studies relating physical activity
to CVD have reported CVD mortality as an endpoint;
two also reported on nonfatal disease, and one re-
ported on CVD hospitalization (Table 4-l). Seven
cohort studies evaluated the association between
level of physical activity and the risk of total CVD
(Kannel and Sorlie 1979; Paffenbarger et al. 1984;
Kannel et al. 1986; Lindsted, Tonstad, Kuzma 1991;
Arraiz, Wigle, Mao 1992; Shermanet al. 1994; LaCroix
et al. 1996). All relied on a single point-in-time
estimate of physical activity, in some cases assessed
as long as 26 years before the end of the observational
period, and four had follow-up periods of 114 years.
Four of the seven studies found both an inverse
association and a dose-response gradient between
level of physical activity and risk of CVD outcome
(Kannel and Sorlie 1979; Paffenbarger et al. 1984;
Kannel et al. 1986; LaCroix et al. 1996). One study
among men found an inverse association among the
moderately active group but less of an effect in the
vigorously active group (Lindsted, Tonstad, Kuzma
199 1). One study of women 50-74 years of age found
no relationship of physical activity with CVD mor-
tality (Sherman et al. 1994).
Five large cohort studies have related cardiores-
piratory fitness to the risk of CVD mortality (Arraiz,
Wigle, Mao 1992; Ekelund et al. 1988; Blair, Kohl,
Paffenbarger 1989; Sandvik et al. 1993; Blair et al.
1995), but only one provided a separate analysis for
women (Blair, Kohl, Paffenbarger 1989). Each of
these studies demonstrated an inverse dose-response
relationship between level of cardiorespiratory fit-
ness and CVD mortality. Three of the five studies
relied on a maximal or near-maximal exercise test to
estimate cardiorespiratory fitness. One study (Blair
et al. 1995) demonstrated that men with low cardio-
respiratory fitness who became fit had a lower risk of
CVD mortality than men who remained unfit.
Taken together, these major cohort studies indi-
cate that low levels of physical activity or cardiores-
piratory fitness increase risk of CVD mortality.
Findings seem to be more consistent for studies of
cardiorespiratory fitness, perhaps because of its
greater precision of measurement, than for those of
reported physical activity. The demonstrated dose-
response relationship indicates that the benefit de-
rived from physical activity occurs at moderate levels
of physical activity or cardiorespiratory fitness and
increases with increasing levels of physical activity
or higher levels of fitness.
Coronary Heart Disease
Numerous studies have examined the relationship
between physical activity and CHD as a specific CVD
outcome. Reviews of the epidemiologic literature
(Powell et al. 1987; Berlin and Colditz 1990; Blair
1994) have concluded that physical activity is strongly
and inversely related to CHD risk. Although physical
exertion may transiently increase the risk of an acute
coronary event among persons with advanced coro-
nary atherosclerosis, particularly among those who
do not exercise regularly (Mittleman et al. 1993;
Willich et al. 1993; Siscovick et al. 1984), physically
active people have a substantially lower overall risk
for major coronary events.
The Effects of Physical Activity on Health and Disease
87

Physical Activity and Health
Table 4-1. Population-based studies of association of physical activity or cardiorespiratory fitness with total
      cardiovascular diseases
Study
Physical activity
Kannel and
Sorlie (1979)
Paffenbarger et al.
(1984)
Kannel et al.
(1986)
Lindsted, Tonstad,
Kuzma
(1991)
Arraiz, Wigle,
Mao (1992)
Sherman et al
(1994)
LaCroix et al.
(1996)
Population
Definition of physical activity     Definition of
or cardiorespiratory fitness       cardiovascular disease
1,909 Framingham (MA)
men and 2,311 women
aged 35-64 years at
14-year follow-up
16,936 US male college
alumni who entered
college between 1916
and 1950; followed
from 1962-l 978
1 ,166 Framingham (MA)
men aged 45-64 years;
24-year follow-up
9,484 Seventh-Day
Adventist men aged
2 30 years; 26-year
follow-up
Stratified probability
sample of Canadians
aged 30-69 years,
conducted in 1978-
1979; 7-year follow-up
1,404 Framingham (MA)
women aged 50-74
years; 16-year
follow-up
1,645 HMO members
age 2 65 years; 4.2-year
average follow-up
Cardiorespiratory fitness
Ekelund et al.     3,106 North American
(1988)        men aged 30-69
          years; 8.5-year
          average follow-up
Blair et al.
(1989)
10,244 men and 3,120
women aged 2 20 years;
8.1 -year average
follow-up
Physical activity index based
on hours per day spent at
activity-specific intensity
Physical activity index estimated
from reports of stairs climbed,
city blocks walked, and sports
played each week
Physical activity index based on
hours per day at activity-specific
intensity; occupational physical
activity classified by physical
demand of work
Self-report to single physical
activity question
Physical activity index
summarizing frequency, intensity,
and duration of leisure-time
activity and household chores
Physical activity index based on
hours per day spent at activity-
specific intensity
Hours of walking per week
Submaximal aerobic capacity
estimated from exercise test
Maximal aerobic capacity
estimated by exercise test
CVD fatal and nonfatal
in men (n = 140 deaths,
n = 435 total cases) and
women (n = 101 deaths)
Death due to CVD
(n = 640)
Death due to CVD
(n = 325)
Death due to CVD
(ICD-8 41 O-458)
(n = 410)
Death due to CVD
(n = 256)
CVD incidence (n = 994)
and mortality (n = 303)
CVD hospitalization
(ICD-9 390-448)
(n = 359)
Death due to CVD
(KID-8 390-458)
(n = 45)
Death due to CVD
(ICD-9 390-448)
in men (n = 66)
and women (n = 7)
88

The Effects of Physical Activity on Health and Disease
Main findings
Dose     Adjustment for confounders
resDonse*    and other comments
Inverse association between physical activity
index and CVD mortality for both men
and women
Inverse association; relative to highest
category (2,000+ kcal/week), relative risk
estimates were 1.28 and 1.84, respectively
Inverse association; for physical activity
index, age-adjusted RR relative to high
activity category = 1.62 for low activity,
I .30 for moderate; for occupational activity,
age-adjusted RR relative to heavy physical
demand category = 1.34 for sedentary, 1.26
for light, 1.09 for medium
Inverse association relative to inactive group;
moderately active RR = 0.79
(95% Cl, 0.58-l .07), highly active RR = 1.02
(95% Cl,O.66-1.58)
Null association across categories of physical
activity index
Null association across quartiles of physical
activity index
Inverse association; compared with walking
4 hrs/week, RR = 0.90 (95% Cl 0.69-l .17)
for walking l-4 hrs/week; RR = 0.73
(95% Cl 0.55-0.96) for walking > 4 hrs/week
Inverse association; adjusted risk estimate of
2.7-fold increased risk of CVD death for a
35 beat/min increase in heart rate for stage II
of exercise test
Inverse association; for men, age-adjusted RR
for lowest 20% compared with upper 40% =
7.9; for middle 40% = 2.5; for women, 9.2
and 3.6
Yes
Control for several confounding variables;
statistical significance only for men after
multivariate adjustment
Yes
Significant dose-response after adjusting for age,
smoking, and hypertension prevalence
Yes
Inverse association constant across all analyses;
inverse association maintained after multivariate
analyses
No
No statistical significance after controlling for
sociodemographic variables, BMI, and dietary
pattern
No
Point estimates adjusted for age, BMI, sex, and
smoking
No
No statistical significance after controlling for
several clinical and sociodemographic
confounding variables
Yes
Multivariate analysis adjusted for age, sex,
functional status, BMI, smoking, chronic
illnesses, and alcohol
Yes
Extensive control for clinical and
sociodemographic confounding influences
Yes
Significant linear dose-response association;
adjusted for age
89

Physical Activity and Health
Table 4-1. Continued
Study
Arraiz, Wigle,
Mao (1992)
Population
Stratified probability
sample of Canadians
aged 30-69 years,
conducted in 1978-
1979; 7-year follow-up
Definition of physical activity     Definition of
or cardiorespiratory fitness       cardiovascular disease
Submaximal aerobic capacity      Death due to CVD
estimated from home step test     (n = 37)
Sandvik et al.
(1993)
1,960 Norwegian men
aged 40-59 years;
average 16-year
follow-up
Maximal aerobic capacity
estimated by exercise test
Death due to CVD
(n = 144)
Blair et al.
(1995)
9,777 US men aged
20-82 years with 2
evaluations; 5.1 -year
average follow-up
Maximal aerobic capacity
estimated by exercise test
Death due to CVD
(ICD-9 390-449.9)
(n = 87)
Thirty-six studies examining the relationship of
physical activity level to risk of CHD have been
published since 1953 (Table 4-2). Studies published
before 1978 predominantly classified physical activ-
ity level byjob title or occupational activities. Studies
thereafter usually defined activity level by recall of
leisure-time activity or by such activity combined
with occupational activity. These later studies were
also able to control statistically for many potentially
confounding variables in addition to age. Most of
these studies focused on men in the age ranges
associated with increasingriskof CHD (30-75 years);
only four included women. Although in several stud-
ies, CHD mortality was the sole outcome variable,
most included both fatal and nonfatal disease. All but
one (Morris et al. 1973) were cohort studies; lengths
of follow-up from baseline assessment ranged from 4
to 25 years. All studies related a single baseline
estimate of physical activity level to risk of CHD
during the follow-up period.
Some study populations have had more than one
follow-up assessment for CHD. For example, three
follow-up assessments (at 10,12, and 23 years) have
been reported for men in the Honolulu Heart Pro-
gram (Yano, Reed, McGee 1984; Donahue et al. 1988;
Rodriguez et al. 1994). Each represented follow-up
further removed from the original determination of
physical activity. Thus, the diminishing effect seen
over time might indicate changing patterns of physical
activity- and thereby a lessening of validity of the
original physical activity classification (Table 4-2).
Oddly, in the 12-year follow-up, the reduction in
CHD risk observed among both active middle-aged
men (RR = 0.7) and active older men (RR = 0.4)
when compared with their least active counterparts
was not diminished by bivariate adjustment for
serum cholesterol, body mass index (BMI), or blood
pressure (Donahue et al. 1988). In the 23-year
follow-up, however, the reduction in CHD risk
among active men (RR = 0.8) was greatly diminished
by simultaneous adjustment for serum cholesterol,
BMI, blood pressure, and diabetes, (RR = 0.95),
leading the authors to conclude that the beneficial
effect of physical activity on CHD risk is likely
mediated by the beneficial effect of physical activity
on these other factors (Rodriguez et al. 1994). These
reports thus illustrate not only the problem of lengthy
follow-up without repeated assessments of physical
activity but also the problem of lack of uniformity in
adjustment for potential confounding factors, as well
as the underlying, thorny problem of adjustment for
multiple factors that may be in the causal pathway
between physical activity and disease. Studies have
in fact varied greatly in the extent to which they have
controlled for potential confounding and in the
factors selected for adjustment.
  Although early studies were not designed to dem-
onstrate a dose-response gradient between physical
90

The Effects of Physical Activity on Health and Disease
Main findings
Inverse association; relative to highest fitness
level, persons in "moderate" and "low"
categories had risks of 0.8 (95% Cl, 0.1-7.6)
and 5.4 (95% Cl, 1.9-l 5.9), respectively
Dose
response*
No
Adjustment for confounders
and other comments
Point estimates adjusted for age, BMI, sex, and
smoking
Inverse association; relative to men in lowest
fitness quartile, multivariate adjusted RR in
quartiles 2, 3, and 4 were 0.59, 0.45, and
0.41, respectively
Yes      Extensive control for confounding influences
Inverse association; relative to men who
remained unfit (lowest 20% of distribution),
those who improved had an age-adjusted RR
Yes
For each minute of improvement in exercise test
time, adjusted CVD mortality risk was reduced
8.6%
of 0.48 (95% Cl,`O.3 l-0.74)
Abbreviations: BMI = body mass index (wt [kg] /ht [ml2 ); CVD = cardiovascular disease: Cl = confidence interval; HMO = health
maintenance organization; ICD = International Classification of Diseases (8 and 9 refer to editions); RR = relative risk.
`A dose-response relationship requires more than 2 levels of comparison. In this column, "NA" means that there were only 2 levels of
comparison: "No" means that there were more than 2 levels but no dose-response gradient was found; "Yes" means that there were
more than 2 levels and a dose-response gradient was found.
activity level and CHD, most found an inverse asso-
ciation: more active persons were found to be at
lower risk of CHD than their more sedentary coun-
terparts. Of the 17 recent studies that found an
inverse relationship and were able to examine dose-
response relationships, 13 (76 percent) demonstrated
an inverse dose-response gradient between level of
physical activity and risk of CHD, whereas 2 showed
a dose-response gradient only for some subgroups.
The relationship between cardiorespiratory fit-
ness and risk of CHD was examined in seven cohort
studies (follow-up range, 4-20 years). All but two
(Lie, Mundal, Erikssen 1985; Erikssen 1986) used
estimates of aerobic power based on submaximal
exercise testing. None of these studies included
women. Similar to the studies of physical activity
and CHD, these all related a single baseline assess-
ment of cardiorespiratory fitness to risk of CHD
during the follow-up period. Most controlled statis-
tically for possible confounding variables. All seven
studies showed an inverse association between
cardiorespiratory fitness and CHD. Of the six
studies that had more than two categories of cardio-
respiratory fitness, all demonstrated an inverse
dose-response gradient.
Two recent meta-analyses of studies of physical
activity and CHD have included independent scoring
for the quality of the methods used in each study
(Powell et al. 1987; Berlin and Colditz 1990). Both
concluded that studies with higher-quality scores
tended to show higher relative risk estimates than
those with lower-quality scores. In the Berlin and
Colditz quantitative meta-analysis, the pooled rela-
tive risk for CHD-comparingrisk for the lowest level
of physical activity with risk for the highest level-
was 1.8 among the studies judged to be of higher
quality. In contrast, the pooled relative risk for the
studies with low-quality scores was in the null range.
CVD Risk Factors in Children
Because CHD is rare in children, the cardiovascular
effects of physical activity in children are assessed
through the relationship of physical activity with
CHD risk factors such as elevated low-density lipo-
protein cholesterol (LDL-C), lowered high-density
lipoprotein cholesterol (HDL-C), and elevated blood
pressure. The presence of CHD risk factors in chil-
dren is of concern because of evidence that athero-
sclerosis begins in childhood (Star-y 1989), that
presence of CHD in adults is related to elevated blood
91

Physical Activity and Health
Table 4-2.  Population-based studies of association of physical activity or cardiorespiratory fitness with coronary
       heart disease
Study
Population
Definition of physical activity
or cardiorespiratory fitness
Definition of coronary
heart disease
Kahn (1963)
Morris et al.
(1966)
Cassel et al.
(1971)
Physical activity
Morris et al.
(1953)
31,000 male employees
of London Transport
Executive aged 35-64
years
Morris and
Crawford (1958)
3,731 case necropsy
studies (decedents aged
45-70 years) conducted
in Scotland, England,
and Wales
Taylor et al.
(1962)
191,609 US white male
railroad industry
employees aged 40-64
years
2,240 Postal Service
employees in the
Washington, D.C., Post
Office between 1906
and 1940; followed
through December 1961
667 London bus
conductors and drivers
aged 30-69 years;
5-year follow-up
3,009 male residents
of Evans County,
Georgia, aged over 40
years in 1960-l 962;
7.25-year average
follow-up
Morris et al.
(1973)
British male executive
grade civil servants
aged 40-60 years;
232 heart attack case-
patients and 428
matched controls .
Brunner et al.
(1974)
5,288 male and 5,229
female residents of 58
Israeli kibbutzim aged
40-69 years; 15-year
follow-up
Occupational classification of job
duties: sedentary drivers and
active conductors
Physical activity at work defined
by coding of last known job title
before death (light, active, heavy)
Physical activity at work defined
by job title for clerks, switchmen,
and section men
Physical activity at work defined
by job title for clerks and carriers
Occupational classification of job
duties as sedentary drivers
and active conductors
Incidence of CHD
(n = 47)
Occupational classification of job   Incidence of CHD
duties as active or sedentary      (n = 337)
48-hour recall of leisure-time
physical activities; activities
defined as capable of reaching
7.5 kcal/min were defined as
vigorous
Work types classified as sedentary
or nonsedentary
First clinical episode of
CHD
Necropsy evaluation of
IMF among persons
dying from
noncoronary causes
Death due to
arteriosclerotic disease
(ICD 420, 422)
in 1955-l 956
Death due to CHD
First CHD attack
(fatal and nonfatal)
Fatal and nonfatal CHD,
males (n = 281) and
females (n = 70)
92

The Effects of Physical Activity on Health and Disease
Main findings
Dose     Adjustment for confounders
response*   and other comments
Inverse association; relative to men whose
main job responsibility was driving buses,
conductors had an age-adjusted risk of first
coronary episode of 0.70
Inverse association; RR for IMF for persons
in light occupations was 1.97 relative to
heavy group; active group rate was
intermediate
Inverse association; RR for arteriosclerotic
disease among clerks was 2.03 relative to
that for section men; risk estimate for
switchmen was 1.46
Inverse and null associations; among
employees classified by their original
occupational category, the age-adjusted risk
for CHD death for clerks relative to carriers
was 1.26
Inverse association; age-adjusted risk of CHD
incidence among drivers was 1.8 relative to
that for conductors
Inverse association; age-adjusted risk of CHD
among sedentary, nonfarm occupations
relative to that for active nonfarm
occupations was 1.8
Inverse association; RR estimate for first
attack among vigorous group = 0.33
compared with nonvigorous group
Inverse association; risk for CHD incidence
among those engaged in sedentary work
compared with that for nonsedentary peers
was 2.52 for men and 3.28 for women
NA
No control for confounding; results were
similar in subgroup of men who died of
CHD-associated conditions
Yes
No control for confounding; one of few
pathology studies
Yes
NA
NA
NA
NA
No control for confounding; specific analyses
were consistent with overall results
No control for confounding; extensive efforts
made to consider and evaluate job transfers
Medical evaluation data used to control
for confounding variables
Data also available on black residents;
comparisons between sedentary and active
occupations not possible
Only study to analyze 48-hour recall
of leisure-time physical activity
(5-minute intervals)
NA
No differences in serum cholesterol
and body weight between groups
93

Physical Activity and Health
Table 4-2. Continued
                   Definition of physical activity    Definition of coronary
Study       Population       or cardiorespiratory fitness      heart disease
Paffenbarger and
Hale (1975)
Paffenbarger et al.
(1977)
Rosenman, Bawol,
Oscherwitz
(1977)
Chave et al.
(1978)
Paffenbarger,
Wing, Hyde
(1978)
Morris et al.
(1980)
Salonen et al.
(1982)
Pomrehn et al.
(1982)
6,351 San Francisco
Bay Area longshoremen
aged 35-74 years;
followed for 22 years,
from 1951 to death
or to age 75
3,686 San Francisco
Bay Area longshoremen
aged 35-74 years;
followed for 22 years,
from 195 1 to death
or to age 75
2,065 white male San
Francisco Bay Area
federal employees aged
35-59 years; 4-year
follow-up
3,591 British male
executive-grade civil
servants aged 40-64
years; 8.5-year average
follow-up from
1968 to 1970
16,936 Harvard male
alumni aged 35-74
years; followed up for
6-l 0 years
17,944 British male
executive grade civil
servants aged 40-64
years; 8.5-year average
follow-up from
1968 to 1970
3,829 women and
4,110 men aged 30-59
years from Eastern
Finland; 7-year
follow-up
61,922 deaths from
1964-l 978 among
Iowa men aged 20 to
64 years
Work-years according to
required energy output: heavy
(5.2-7.5 kcal/min), moderate
(2.4-5.0 kcal/min), and light
(1.5-2.0 kcal/min)
Work-years according to
required energy output: high
(5.2-7.5 kcal/min), intermediate
(2.4-5.0 kcaI/min), and light
(1.5-2.0 kcal/min)
Occupational physical activity;,
estimated caloric expenditure for
work and nonwork activity
48-hour leisure-time physical
activity recall; activities capable
of reaching 7.5 kcal/min defined
as vigorous
Physical activity index based on
self-report of stairs climbed, blocks
walked, and strenuous sports play
48-hour recall of leisure-time
physical activities; activities
defined as capable of reaching
7.5 kcal/min were defined as
vigorous
Dichotomous assessment of
occupational and leisure-time
physical activity (low/high)
Occupational classification;
farmers vs. nonfarmers
CHD death (ICD-7 420)
(n = 598)
CHD death ([CD-7 420)
(n = 395)
     i
Fatal and nonfatal CHD
(n = 65)
Fatal and nonfatal first
CHD attack (n = 268)
Fatal and nonfatal first
heart attack (n = 572)
Fatal and nonfatal first
heart attack (n =l ,138)
Fatal acute ischemic heart
disease (ICD-8, 410-412)
(n = 89 men and 14 women)
and acute myocardial
infarction (ICD-8,41 O-41 1)
(n = 210 men and 63 women)
Death from ischemic
heart disease
94

The Effects of Physical Activity on Health and Disease
Main findings
Dose     Adjustment for confounders
resuonse'   and other comments
Inverse association; relative to heavy
category, age-adjusted RR of CHD death was
1.70 in moderate and 1.80 in light categories
Yes
No control for confounding variables; efforts
made to evaluate job changes in the cohort
over time
Inverse association overall, inverse for
younger birth cohorts and null for older
cohorts; relative to high category,
age-adjusted RRs of CHD death were 1.8
in intermediate and 1.60 in light categories
No/Yes
Dose response noted in age-adjusted rates
only for two younger groups; two older
groups exhibited no association
Null association
No
Relatively short-term follow-up
Inverse association; risk of CHD attack
among men reporting nonvigorous exercise
relative to men reporting vigorous exercise
was 2.2
NA
Inverse association; age-adjusted RR of first     Yes
heart attack for men who expended fewer than
2,000 kcal/week was 1.64 compared with
men who expended 2,000 or more kcal/week
Inverse association; age-adjusted risk
of CHD attack among men reporting
nonvigorous exercise relative to those
reporting vigorous exercise was 2.2
NA
Inverse association; RR of acute
myocardial infarction for men and women
with low levels of physical activity at work =
1.5 (90% Cl, 1.2-2.0) for men and 2.4
(90% Cl, 1.5-3.7) for women
NA
Preliminary report of further data of
Morris et al. 1980
History of athleticism not associated with
lower risk unless there was also current
energy expenditure
Increased risk similar for fatal and
nonfatal attacks
No associations with leisure-time physical
activity; extensive adjustment for
confounding
Farm men had significantly less mortality than   NA      No adjustment for confounding
expected from the experience in the general
Population of Iowa men (SMR = 0.89)
95

Physical Activity and Health
Table 4-2. Continued
                   Definition of physical activity    Definition of coronary
Study        Population       or cardiorespiratory fitness       heart disease
Garcia-Palmieri
et al. (1982)
Paffenbarger et al.
(1984)
Yano, Reed,
McGee (1984)
Menotti and
Seccareccia
(1985)
Kannel et al.
(1986)
Lapidus and
Bengtsson (1986)
Leon et al.
(1987)
Pekkanen et al.
(1987)
Sobolski et al.
(1987)
8,793 Puerto Rican
men aged 45-64 years;
followed for up to 8.25
years
16,936 US male college
alumni who entered
college between 1916
and 1950; followed
from 1962 to 1978
7,705 Hawaiian men of
Japanese ancestry aged
45-68 years with no
history of heart disease;
1 O-year follow-up
99,029 Italian male
railroad employees
aged 40-59 years;
S-year follow-up
1 ,166 Framingham (MA)
men aged 45-64 years.;
24-year follow-up
1,462 Swedish women
aged 38-60 years;
follow-up between
1968 and 1981
12,138 North American  Leisure-time physical activity
men at high risk for    index; energy expenditure
CHD, aged 35-57 years;  (minutes/week)
Usual 24hour physical activity
index based on hours/day at
specific intensity
Physical activity index estimated
from reports of stairs climbed,
city blocks walked, and sports
played each week
Self-report of 24hour habitual
physical activity in 1965-l 968
Occupational physical activity
(heavy, moderate, sedentary)
Physical activity index based on
hours per day at activity-specific
intensity; occupational physical
activity classified by physical
demand of work
Physical activity at work and
during leisure hours, lifetime, and
during previous years
7-year average follow-up
636 apparently healthy  Occupational and transport/
Finnish men aged     recreational physical activity
45-64 years, followed  (high or low)
for 20 years from   .
1964 baseline
2,109 Belgian men
aged 40-55 years in
1976-l 978; 5-year
follow-up
Occupational and leisure-time
physical activity (4 categories
each)
CHD incidence other than
angina pectoris (n = 335)
Death due to CHD
(n = 441)
Incident cases of fatal and
nonfatal CHD (n = 511)
Fatal myocardial infarction
(n = 614)
Death due to CHD
(n = 220)
Nonfatal myocardial
infarction and angina
pectoris
Fatal and nonfatal CHD
(n = 781; 368 fatal)
Death due to CHD
(n = 106)
Incident cases of fatal and
nonfatal myocardial
infarction and sudden
death (n = 36)
96

The Effects of Physical Activity on Health and Disease
                              Dose
Main findings                response'
Inverse association; physical activity index     Yes
was significantly related to lower risk of CHD
in urban as well as rural men
Inverse association; relative to highest
category of index (2,000+ kcal/week),
risk estimates in next two lower categories
were 1.28 and 1.84, respectively
Yes
Inverse association; significant only for all
CHD; no significant association for various
subtypes
NA
Inverse association; relative to sedentary,
men in moderate and heavy occupational
activity had RRs of 0.97 and 0.64,
respectively
Yes
Inverse association; age-adjusted RR (relative   Yes
to high category) = 1.38 (low), 1.21 (moderate);
for occupational activity, age-adjusted RR
(relative to heavy category) = 1.27 (sedentary),
1.22 (light), 0.99 (medium)
Inverse association only for leisure-time
physical activity; RR = 2.8 (95% Cl, 1.2-
6.5) comparing low leisure-time physical
activity with all other categories
NA      Adjusted for age
Inverse association; multivariate adjusted
risk estimate (relative to low activity tertile)
was 0.90 (95% Cl, 0.76-l .06) for more
active and 0.83 (95% Cl, 0.70-0.99) for
most active
Yes
Inverse association; adjusted RR for men
in low physical activity group was 1.30
fp = 0.17)
NA
Null association for both leisure-time and
occupational physical activity
No
Adjustment for confounders
and other comments
Significant inverse relationship for CHD
after multivariate adjustment
Significant dose-response after adjusting for
age, smoking, and hypertension prevalence
Adjusted for age, blood pressure, cholesterol,
BMI, serum glucose, vital capacity, etc.
Adjusted for age
Inverse association constant across all
analyses and maintained after controlling
for multivariate confounding
Dose response for fatal and nonfatal cases
combined but not for CHD death or sudden
death separately
Association limited to second half
of follow-up period
One of two studies to simultaneously
evaluate associations of physical activity,
fitness, and CHD
97

Physical Activity and Health
Table 4-2. Continued
                   Definition of physical activity    Definition of coronary
Study       Population       or cardiorespiratory fitness      heart disease
Donahue et al.
(1988)
Salonen et al.
(1988)
lohansson et al.
(1988)
Slattery, Jacobs,
Nichaman
(1989)
Morris et al.
(1990)
Lindsted,
Tonstad,
Kuzma
(19911
Shaper and
Wannamethee
(1991)
Seccareccia and
Menotti (1992)
Hein,
Suadicani,
Gyntelberg
(1992)
7,644 Hawaiian men of
Japanese ancestry aged
45-64 years with no
history of heart disease;
12-year follow-up
15,088 Eastern Finnish
men and women aged
30-59 years; 6-year
follow-up
7,495 Goteburg men
aged 47-55 years at
entry; 11.8-year
average follow-up
3,043 US male
railroad employees;
followed for
17-20 years
9,376 British male
middle grade
executives aged 45-64
years; 9.3-year
average follow-up
9,484 Seventh-Day
Adventist men aged
2 30 years; 26-year
follow-up
7,735 British men aged
40-59 years; 8.5-year
follow-up
1,712 men from
Northern and Central
Italy, aged 40-59 years,
initially examined in
1960; 25-year follow-up
4,999 Copenhagen
men aged 40-59 years;
17-year follow-up
Self-report of 24hour habitual
physical activity in 1965-l 968;
3-point scale defined by tertiles
of distribution
Self-reported leisure-time and
occupational physical activity
(4 levels collapsed into 2
categories each)
Physical activity at work and
physical activity during leisure
time (4-point scale for each)
Leisure-time physical activity
index (kcal/week)
Leisure-time physical activity
reported over previous 4 weeks;
energy expenditure values
ascribed to reported activities
Self-report to single physical
activity question
Self-report of physical activity at
baseline; 6-point scale
Occupational physical activity
(self-report): sedentary,
moderate, and heavy
Leisure-time physical activity
(4-point scale)
Incident cases of fatal
and nonfatal CHD
(n = 444)
Death due to CHD
(ICD-8 41 O-41 4)
(n=102
90 men, 12 women)
Incident cases of fatal
and nonfatal CHD
Death due to CHD
(ICD-8 41 o-41 4)
Fatal and nonfatal CHD
(ICD-8 41 o-41 4)
(n = 474)
lschemic heart disease
mortality
(ICD-8 410-414)
(n = 1,351)
Fatal and nonfatal heart
attack (n = 488)
Death due to CHD
Fatal myocardial
infarction
(ICD-8 41 o-41 4)
(n = 266)
from 1970/l 971
98

The Effects of Physical Activity on Health and Disease
Dose     Adjustment for confounders
Main findings
response*
and other comments
Inverse association; RR among active men
relative to sedentary men was 0.69 (95% Cl,
0.53-0.88) for men aged 45-64 and 0.43
(95% Cl, 0.1 g-0.99) for older men aged 65-74
Inverse association; occupational: adjusted
RR among inactive was 1.3 (95% Cl,
1.1-1.6) relative to active; adjusted RR of
CHD among leisure-time active was 1.2
(95% Cl, 1.0-l .5)
Null association between physical activity at
work and CHD risk; inverse association (not
statistically significant) between leisure-time
physical activity and CHD
Inverse association; adjusted risk estimate
(relative to highest physical activity category)
was 1.28 for sedentary group (not statistically
significant)
Inverse association; age-adjusted RR for
3 episodes per week of vigorous physical
activity relative to sedentary group was 0.36
Null association; risk estimates of CHD
death exhibited a U-shaped relationship
with increasing physical activity levels
Inverse association only for 2 activity levels;
RR compared with sedentary for increasing
physical activity levels: occasional 0.9
(95%CI, 0.5-l .3), light 0.9 (95% Cl, 0.6-l .4),
moderate 0.5 (95% Cl, 0.2-0.8), moderately
vigorous 0.5 (95% Cl, 0.3-0.9), and
vigorous 0.9 (95% Cl, 0.5-l .8)
Inverse association; age-adjusted RRfor
moderate and heavy categories compared
with that for sedentary group was 0.69 and
0.58, respectively
Inverse association; relative to more active
men (categories 2-4 of index), least active
men had an adjusted RR of CHD of 1.59
(95% Cl, 1.14-2.21)
Yes
Adjusted for age, alcohol use, and smoking;
bivariate adjustment for cholesterol, BMI,
and blood pressure did not alter findings;
follow-up to Yano, Reed, McGee (1984)
NA
Point estimate for low leisure-time physical
activity was adjusted toward the null after
consideration of other CHD risk factors
No
Extensive control for confounding variables;
ancillary analysis on postinfarction patients
also yielded null association
Yes
Adjusted for age, smoking, cholesterol,
and blood pressure
Yes
No adjustment for confounding; association
only noted for vigorous physical activity
No
No
Yes
Possible protective association among
moderate activity group
No clear linear trend
Inverse association remained statistically
significant after adjustment for confounding
No
One of two studies to simultaneously
evaluate activity and fitness in relation
to CHD mortality
99

Physical Activity and Health
Table 4-2. Continued
                   Definition of physical activity    Definition of coronary
Study       Population       or cardiorespiratory fitness      heart disease
Shaper,
Wannamethee,
Walker (1994)
5,694 British men aged
40-59 years; 9.5-year
follow-up
Rodriguez et al.
(1994)
7,074 Hawaiian men
of Japanese ancestry
aged 45-68 years;
23-year follow-up
Cardiorespiratory fitness
Peters et al.
(1983)
2,779 male Los Angeles
County public safety
employees aged
< 55 years; 4.8-year
average follow-up
Lie, Mundal,
Erikssen
(1985)
Erikssen (1986)
Sobolski et al.
(1987)
Ekelund et al.
(1988)
Slattery et al.
(1988)
2,431 US male railroad
employees; 17- through
20-year follow-up
Hein,        4,999 Copenhagen
Suadicani,      men aged 40-59 years;
Gyntelberg     17-year follow-up
(1992)         from 1970/l 971
2,014 Norwegian
employed men aged
40-59 years; 7-year
follow-up
1,832 Norwegian
men aged 40-59 years;
-/-year average
follow-up
2,109 Belgian men
aged 40-55 years in
1976-l 978; 5-year
follow-up
3,106 North American
men aged 30-69 years;
8.5-year average
follow-up
Self-report of physical activity at
baseline; 6-point scale data
analyzed by hypertensive status
Self-report of 24hour habitual
physical activity in 1965-l 968
Submaximal aerobic capacity
estimated from cycle ergometer
test; age-specific median split used
to determine low/high fitness
Near maximal cycle ergometer
exercise test; total work in
quartiles
Near maximal cycle ergometer
exercise test; total work in
quartiles
Submaximal aerobic capacity
estimated from cycle ergometry
test
Submaximal aerobic capacity
estimated from exercise test
Submaximal exercise heart rate on
standard (3 min) treadmill test
evaluation
Submaximal aerobic capacity
estimated from cycle ergometer
exercise test
Fatal and nonfatal heart
attack (n = 311; 165
normotensive, 146
hypertensive)
Incident cases of fatal
and nonfatal CHD
(n = 340)
Incident cases of fatal
and nonfatal myocardial
infarction (n = 36)
Incident cases of fatal
and nonfatal CHD
Incident cases of fatal
and nonfatal myocardial
infarction and CHD death
Incident cases of fatal
and nonfatal myocardial
infarction and sudden
death (n = 36)
Death due to CHD
(ICD-8 41 o-41 4)
Death due to CHD
(ICD-8 41 o-41 4)
Fatal myocardial infarction
(ICD-8 41 o-41 4)
(n = 266)
100