Articles

Minimum amount of physical activity for reduced mortality
and extended life expectancy: a prospective cohort study
Chi Pang Wen*, Jackson Pui Man Wai*, Min Kuang Tsai, Yi Chen Yang, Ting Yuan David Cheng, Meng-Chih Lee, Hui Ting Chan, Chwen Keng Tsao,
Shan Pou Tsai, Xifeng Wu

Summary
Lancet 2011; 378: 1244–53
Published Online
August 16, 2011
DOI:10.1016/S01406736(11)60749-6
See Comment page 1202
*These authors shared ﬁrst
authorship
Institute of Population Science,
National Health ResearchInstitutes, Zhunan, Taiwan(C P Wen MD, M K Tsai MS,Y C Yang MS, H T Chan MS);
China Medical University
Hospital, Taichung, Taiwan(C P Wen, M K Tsai, Y C Yang);
Laboratory for Exercise
Physiology Research, Instituteof Sport Science, National
Taiwan Sport University,
Taoyuan, Taiwan(J P M Wai PhD); Department of
Epidemiology, University ofWashington, Seattle, WA, USA(T Y D Cheng MS); Institute ofMedicine and Department of
Family and Community
Medicine, Chung Shan Medical
University and Hospital,
Taichung, Taiwan(M-C Lee MD); MJ HealthManagement Institution,
Taipei, Taiwan (C K Tsao BS);
University of Texas School of
Public Health, Houston, TX,
USA (S P Tsai PhD); andDepartment of Epidemiology,
MD Anderson Cancer Center,
Houston, TX, USA (X Wu MD)
Correspondence to:
Dr Chi Pang Wen, National
Health Research Institutes,
35 Keyan Road, Zhunan,
Miaoli County 350, Taiwan
cwengood@nhri.org.tw

1244

Background The health beneﬁts of leisure-time physical activity are well known, but whether less exercise than therecommended 150 min a week can have life expectancy beneﬁts is unclear. We assessed the health beneﬁts of a rangeof volumes of physical activity in a Taiwanese population.
Methods In this prospective cohort study, 416 175 individuals (199 265 men and 216 910 women) participated in astandard medical screening programme in Taiwan between 1996 and 2008, with an average follow-up of 8·05 years(SD 4·21). On the basis of the amount of weekly exercise indicated in a self-administered questionnaire, participants
were placed into one of ﬁve categories of exercise volumes: inactive, or low, medium, high, or very high activity. We
calculated hazard ratios (HR) for mortality risks for every group compared with the inactive group, and calculated life
expectancy for every group.
Findings Compared with individuals in the inactive group, those in the low-volume activity group, who exercised for an
average of 92 min per week (95% CI 71–112) or 15 min a day (SD 1·8), had a 14% reduced risk of all-cause mortality(0·86, 0·81–0·91), and had a 3 year longer life expectancy. Every additional 15 min of daily exercise beyond the minimum
amount of 15 min a day further reduced all-cause mortality by 4% (95% CI 2·5–7·0) and all-cancer mortality by 1%(0·3–4·5). These beneﬁts were applicable to all age groups and both sexes, and to those with cardiovascular diseaserisks. Individuals who were inactive had a 17% (HR 1·17, 95% CI 1·10–1·24) increased risk of mortality compared withindividuals in the low-volume group.
Interpretation 15 min a day or 90 min a week of moderate-intensity exercise might be of beneﬁt, even for individuals
at risk of cardiovascular disease.
Funding Taiwan Department of Health Clinical Trial and Research Center of Excellence and National HealthResearch Institutes.

Introduction
Much evidence suggests that 150 min or more a week ofleisure-time physical activity (LTPA) can have substantial
health beneﬁts for an individual.1,2 Guidelines such as the2008 physical activity guidelines for Americans1 andWHO’s 2010 Global Recommendations on Physical
Activity for Health1,3 have drawn attention to the healthbeneﬁts of this amount of weekly exercise. Because
barriers exist to meet this 30 min a day, 5 day a week
recommendation (eg, time constraints or an individual’s
uncertainty about the amount of exercise needed to
beneﬁt health), LTPA is an underused public healthintervention. East Asians tend to be less physically active
than individuals in western countries, and also tend to
exercise at lower intensity.4,5 A third of the American adult
population met this recommendation,1 whereas less thana ﬁfth of the adult population did in East Asian countries
such as China, Japan, or Taiwan.4,5 Whether levels ofphysical activity below the recommended 150 min a week
are adequate to generate health beneﬁts is unclear.
Identiﬁcation of a minimum amount of exercise—or minimum dose1—suﬃcient to reduce mortality isdesirable because a small amount of exercise can be easierto achieve. Furthermore, patients might be more easily

motivated to exercise if their doctor recommends an easily
manageable amount, especially if health messages are
simple. Because east Asians visit their doctors frequently,6plenty of opportunities for health communication andprescription of exercise exist.7 However, such opportunities
to prescribe exercise are sometimes missed because most
doctors are expected to treat only diseases, having little
time to modify a behaviour that is not directly related tothe disease if not requested by a patient. If healthenhancing physical activity were to be prescribed, itshould be related to the disease in question, and therecommended amount should be kept to a minimum toincrease the chances of adherence.
The objective of this study is to assess the healthbeneﬁts of diﬀerent volumes of physical activity in a large
cohort in Taiwan, and to investigate whether less than
150 min a week of exercise is suﬃcient to reduce mortality
or extend life expectancy.

Methods
Data collection
In this historically prospective cohort study, the cohort
consisted of 416 175 healthy individuals aged 20 years orolder (199 265 men and 216 910 women) who participatedwww.thelancet.com Vol 378 October 1, 2011

Articles

in a standard medical screening programme run by a
private ﬁrm (MJ Health Management Institution, Taipei,
Taiwan)—all participants were followed up between 1996
and 2008.8 The 13-year study period yielded 3·35 million
person-years of follow-up, with an average follow-up of
8·05 years (SD 4·21). Every individual’s identiﬁcation
number was matched with the National Death ﬁle and the
National Cancer Registry ﬁle.8
Every participant signed a consent form authorising
MJ Health Management Institution to process data
generated from medical screening. Ethical reviews(Institutional Review Boards) were processed andapproved at MJ Health Management Institution and at
National Health Research Institutes in Taiwan. Data
related to individual identiﬁcation were removed andremained anonymous during the entire study process.
Inactive

All participants

Low volume

Every participant completed a self-administered questionnaire of their medical history and lifestyle information.
All participant were encouraged to visit on a yearly basis;the same questionnaires were ﬁlled out on every visit, but
results from the initial visit only were used. An individual’s
LTPA level was ascertained through three multiple-choicequestions. First, participants were asked to classify thetypes and intensities of weekly LTPAs that they did during
the previous month, with several examples of exercise
types given under four intensity categories: light(eg, walking), moderate (eg, brisk walking), mediumvigorous (eg, jogging), or high-vigorous (eg, running). On
the basis of Ainsworth’s compendium of physicalactivities,9 we assigned a metabolic equivalent value (MET;1 MET=1 kcal per h per kg of bodyweight) of 2·5 for light,
4·5 for moderate, 6·5 for medium-vigorous, or 8·5 forPhysical activity meeting recommendation
Medium volume

High volume

Very high volume

Total

56 899 (14%)

21 730 (5%)

20 390 (5%)

99 019 (24%)

226 493 (54%)

90 663 (22%)

Male

96 798 (49%)

44 246 (22%)

31 593 (16%)

13 184 (7%)

13 444 (7%)

58 221 (29%)

Female129 695 (60%)

46 417 (21%)

25 306 (12%)

8546 (4%)

6946 (3%)

40 798 (19%)

Sex

Age (years)
20–39

137 307 (59%)

54 832 (24%)

24 898 (11%)

8366 (4%)

5823 (3%)

39 087 (17%)

40–59

67 311 (50%)

27 545 (21%)

21 580 (16%)

9834 (7%)

7384 (6%)

38 798 (29%)≥60

21 875 (43%)

8286 (16%)

10 421 (20%)

3530 (7%)

7183 (14%)

21 134 (41%)
30 600 (29%)

Education
Middle school or lower

57 633 (54%)

17 789 (17%)

15 911 (15%)

6752 (6%)

7997 (8%)

High school

54 252 (57%)

20 469 (21%)

11 666 (12%)

4267 (4%)

4589 (5%)

20 522 (22%)

Junior college

46 289 (54%)

21 139 (25%)

11 221 (13%)

3959 (5%)

3270 (4%)

18 450 (21%)

College or higher

50 202 (46%)

30 357 (28%)

17 431 (16%)

6440 (6%)

4319 (4%)

28 190 (26%)

Physical labour at work
Mostly sedentary

110 178 (50%)

54 326 (25%)

33 304 (15%)

11 932 (5%)

9867 (4%)

55 103 (25%)

Sedentary with occasional walking

61 627 (54%)

25 685 (23%)

15 493 (14%)

6004 (5%)

5246 (5%)

26 743 (23%)

Mostly standing or walking

24 509 (60%)

6877 (17%)

4745 (12%)

2198 (5%)

2833 (7%)

9776 (24%)

6733 (62%)

1397 (13%)

1105 (10%)

561 (5%)1008 (9%)

2674 (25%)
65 749 (24%)

Hard labour
Smoking
Never smoker

140 169 (52%)

62 478 (23%)

38 867 (14%)

13 986 (5%)

12 896 (5%)

Ex-smoker

10 338 (44%)

5016 (21%)

4139 (18%)

1905 (8%)

2202 (9%)

8246 (35%)

Smoker

50 272 (56%)

18 829 (21%)

11 819 (13%)

4561 (5%)

4414 (5%)

20 794 (23%)

Drinking
Never drinker

157 766 (54%)

67 506 (23%)

41 113 (14%)

14 719 (5%)

13 216 (4%)

69 048 (23%)

Occasional drinker

26 122 (45%)

13 955 (24%)

9287 (16%)

4191 (7%)

4213 (7%)

17 691 (31%)

Regular drinker

14 938 (54%)

5102 (19%)

3934 (14%)

1622 (6%)

1949 (7%)

7505 (27%)

18·5–24 kg/m²

143 870 (53%)

60 640 (23%)

37 156 (14%)

14 148 (5%)

13 190 (5%)

64 494 (24%)

25–29 kg/m²

49 035 (51%)

19 621 (21%)

14 665 (15%)

5991 (6%)

5911 (6%)

26 567 (28%)≥30 kg/m²

8989 (58%)

3194 (20%)

2019 (13%)

763 (5%)662 (4%)3444 (22%)

Body mass index

Systolic blood pressure<120 mm Hg

130 465 (58%)

51 187 (23%)

26 414 (12%)

9531 (4%)

7497 (3%)

43 442 (19%)

120–139 mm Hg (pre-hypertension)

63 579 (52%)

26 578 (22%)

18 476 (15%)

7322 (6%)

6798 (6%)

32 596 (27%)≥140 mm Hg or receiving drugs(hypertension)

31 517 (47%)

12 866 (19%)

11 991 (18%)

4871 (7%)

6090 (9%)

22 952 (34%)(Continues on next page)www.thelancet.com Vol 378 October 1, 20111245

Articles

Inactive

Low volume

Physical activity meeting recommendation
Medium volume

High volume

Very high volume

Total(Continued from previous page)
Fasting blood glucose<6·1 mmol/L

201 128 (55%)

82 342 (22%)

49 589 (13%)

18 818 (5%)

17 087 (5%)

85 494 (23%)

6·1–6·9 mmol/L (pre-diabetes)

11 548 (50%)

4542 (20%)

3734 (16%)

1558 (7%)

1673 (7%)

6965 (30%)≥7 mmol/L or receiving drugs(diabetes)

9666 (50%)

3428 (18%)

3402 (18%)

1297 (7%)

1592 (8%)

6291 (32%)<6·2 mmol/L

200 392 (55%)

80 754 (22%)

48 930 (13%)

18 648 (5%)

17 217 (5%)

84 795 (23%)≥6·2 mmol/L or receiving drugs(hypercholesterolaemia)

24 950 (51%)

9849 (20%)

7941 (16%)

3075 (6%)

3166 (6%)

14 182 (29%)

No

198 154 (55%)

80 133 (22%)

48 002 (13%)

18 693 (5%)

16 830 (5%)

83 525 (23%)

Yes

28 339 (52%)

10 530 (19%)

8897 (16%)

3037 (6%)

3560 (7%)

15 494 (29%)

No

187 187 (54%)

77 335 (22%)

48 026 (14%)

18 430 (5%)

16 750 (5%)

83 206 (24%)

Yes

24 209 (52%)

8906 (19%)

7113 (15%)

2806 (6%)

3341 (7%)

13 260 (29%)

Total cholesterol

Metabolic syndrome (NCEP-ATP III)

Chronic kidney disease

Data are n (%). NCEP-ATP III=National Cholesterol Education Program-Adult Treatment Panel III.

Table 1: Characteristics of the participants, by volume of leisure-time physical activity

high-vigorous exercise. For individuals who indicatedactivities in more than one intensity category, a weighted
MET value was assigned, dependent on the length of timeengaged in each category. The second question asked forthe duration per week spent on the diﬀerent LTPA
activities within the previous month. Most individuals
classiﬁed as inactive did no LTPA at all, but a small
proportion (12·5%, 28 311 of 226 493) exercised less than 1
h a week, an amount regarded as inactive elsewhere.9
With LTPA volume being the product of intensity (MET)and duration of exercise (h), the calculated MET-h per weekof each individual was placed into one of the ﬁve categories:
inactive (<3·75 MET-h), low (3·75–7·49 MET-h), medium(7·50–16·49 MET-h), high (16·50–25·49 MET-h), or very
high (≥25·50 MET-h), in accordance with classiﬁcations in
the 2008 physical activity guidelines for Americans.1 In
each LTPA category, we also classiﬁed each participant by
exercise intensity into one of two groups: moderateintensity exercise or vigorous-intensity exercise. The
moderate-intensity category consisted of individuals who
did no vigorous-intensity exercise, by excluding those who
indicated that they did no medium-vigorous or highvigorous exercise. All other individuals were put in thevigorous-intensity group. The third question was about theamount of physical activity done at work, classifying
individuals into one of four diﬀerent activity levels, from a
low level of mainly sedentary work to a high level of hard
physical labour.
Participants were classiﬁed as obese on the basis of the
Asian deﬁnition of a body mass index (BMI) of 25 ormore.10 Metabolic syndrome was deﬁned on the basis of
US National Cholesterol Education Program-Adult
Treatment Panel III criteria11 and chronic kidney disease,deﬁned by the Kidney Disease Outcomes Quality Initiative1246

clinical practice guidelines.12,13 Individuals were deﬁned ashaving diabetes if they had a history of diabetes or if they
had positive diabetes screening results (fasting blood
glucose concentration ≥7 mmol/L). Hypertension was
identiﬁed by medical history or positive screening results(systolic pressure ≥140 mm Hg). Pre-hypertension (asystolic pressure of 120–139 mm Hg) and pre-diabetes (afasting blood glucose concentration of 6·1–6·9 mmol/L)
were deﬁned on the basis of screened laboratory results.
Individuals were regarded as regular alcohol drinkers ifthey consumed two or more alcoholic drinks a day on
three or more days a week, and occasional drinkers if they
consumed less than regular drinkers.

Statistical analysis
The primary analysis was done with data from allparticipants who completed the LTPA questionnaire—participants were excluded only in the subgroup
analyses. We calculated hazard ratios (HR) to compare
mortality risks between individuals in diﬀerent exercisegroups (grouped by volume of exercise) and those in theinactive group. We used a Cox proportionate model toanalyse categorical and continuous variables for LTPA.
Categorical variables were sex, education (four levels),
physical labour at work (four levels), smoking (neversmoker, ex-smoker, and smoker), drinking (non-drinker,
occasional drinker, and regular drinker), diabetes,
hypertension, and history of cancer. Continuous
variables were age, fasting blood glucose, systolic bloodpressure, total cholesterol, and BMI. The proportional
hazard assumption was examined and met by plotting
the log minus log survival curves and survival times
against cumulative survival. Two-way interactions
between each of 13 confounders and LTPA volumes
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Articles

Low volume

Physical activity meeting recommendation

Total

Moderate Vigorous

Medium volume
Total

Moderate Vigorous

Total

Moderate Vigorous

Total

Moderate Vigorous

Total

Moderate Vigorous

Number ofindividuals (%)

90 663(22%)

86 424
(21%)

4239
(1%)

56 899(14%)

43 924(11%)

12 975(3%)

21 730(5%)

15 215
(4%)

6515
(2%)

20 390
(5%)

9595
(2%)

10 795(3%)

99 019(24%)

68 734(17%)

30 285(7%)

Duration (minper week)

91·9(10·5)

92·0(10·7)

90·0
(0)

222·1
(85·7)

254·0(66·7)

114·1(44·9)

361·6(120·2)411·9(103·8)243·9(57·7)

523·5
614·4(161·6) (128·4)

442·7(144·3)

314·8
339·3
(164·8) (154·6)

259·1(173·4)

Intensity (MET)

3·0
(0·8)

3·0
(0·8)

3·8
(0·2)

3·7
(1·5)

3·0
(0·8)

6·0
(1·1)

4·1
(1·5)

3·4
(0·9)

5·7
(1·2)

5·0
(1·7)

3·6
(1·0)

6·2
(1·1)

4·0
(1·6)

3·2
(0·9)

6·0
(1·1)

Volume (MET-h
per week)

4·6
(1·3)

4·6
(1·3)

5·7
(0·2)

11·9
(2·9)

12·3
(3·0)

10·7
(2·0)

22·0
(2·8)

22·0
(3·2)

21·9
(1·3)

40·7
(13·5)

35·8
(8·8)

45·2
(15·4)

20·1(13·1)

17·7
(9·3)

25·4
(17·9)

Energy expended(kcal per week)

285·8(103·6)282·8(104·0)347·3(69·7)

751·8(233·3)770·4(244·9)688·7(175·1)1406·9(321·0)1397·5(340·5)1428·9(268·9)2576·0 2256·3(930·4) (733·6)

2865·8(993·0)1268·3 1116·6(858·4) (643·8)

High volume

Very high volume

Total

1615·0(1141·9)

Data are n (%) or mean (SD). MET=metabolic equivalent.

Table 2: Mean activity characteristics of participants, by exercise volume and intensity

Number of Inactive
individuals

Low volume

Physical activity meeting recommendation

Deaths (n) HR

Deaths (n) HR (95% CI)

Medium volume

High volume

Very high volume

Total

Deaths (n) HR (95% CI)

Deaths (n) HR (95% CI)

Deaths (n) HR (95% CI)

Deaths (n) HR (95% CI)

416 175

5688

1

1877

0·86*
(0·81–0·91)

1660

0·80*
(0·75–0·85)

742

0·71*
(0·65–0·77)

813

0·65*
(0·60–0·70)

3215

0·74*
(0·70–0·77)

Moderate

··

··

··

1830

0·86*
(0·82–0·92)

1484

0·82*
(0·77–0·87)

660

0·73*
(0·66–0·80)

499

0·68*
(0·62–0·75)

2643

0·77*
(0·73–0·81)

Vigorous

··

··

··

47

0·73*
(0·54–0·98)

176

0·67*
(0·57–0·78)

82

0·60*
(0·48–0·76)

314

0·60*
(0·53–0·68)

572

0·62*
(0·57–0·68)

All cancer

··

2185

1

755

0·90*
(0·83–0·99)

659

0·85*
(0·77–0·93)

318

0·85*
(0·75–0·97)

355

0·78*
(0·69–0·88)

1332

0·83*
(0·77–0·90)

Moderate

··

··

··

736

0·91*
(0·83–0·99)

576

0·86*
(0·78–0·95)

274

0·86*
(0·75–0·99)

211

0·81*
(0·70–0·95)

1061

0·85*
(0·78–0·92)

Vigorous

··

··

··

19

0·77
(0·48–1·23)

83

0·80
(0·63–1·00)

44

0·80
(0·59–1·11)

144

0·74*
(0·62–0·88)

271

0·76*
(0·67–0·88)

Cardiovasculardisease

··

1100

1

357

0·81*
(0·71–0·93)

352

0·79*
(0·69–0·90)

138

0·61*
(0·50–0·74)

155

0·55*
(0·46–0·66)

645

0·68*
(0·61–0·76)

Moderate

··

··

··

348

0·82*
(0·72–0·93)

325

0·81*
(0·71–0·93)

123

0·62*
(0·50–0·76)

100

0·56*
(0·45–0·70)

548

0·71*
(0·63–0·80)

Vigorous

··

··

··

9

0·70
(0·31–1·57)

27

0·56*
(0·37–0·86)

15

0·55*
(0·32–0·94)

55

0·54*
(0·41–0·72)

97

0·55*
(0·44–0·69)

Ischaemic heartdisease

··

310

1

89

0·75*
(0·58–0·96)

104

0·80
(0·63–1·02)

26

0·39*
(0·24–0·61)

51

0·57*
(0·41–0·80)

181

0·65*
(0·52–0·79)

Moderate

··

··

··

88

0·75*
(0·58–0·97)

96

0·82
(0·64–1·06)

24

0·40*
(0·25–0·65)

36

0·64*
(0·43–0·94)

156

0·69*
(0·55–0·85)

Vigorous

··

··

··

1

0·41
(0·06–2·91)

8

0·61(0·29–1·30)

2

0·29(0·07–1·17)

15

0·45*
(0·25–0·81)

25

0·47*
(0·30–0·74)

··

459

1

154

0·88
(0·72–1·07)

141

0·76*
(0·62–0·94)

68

0·73*
(0·55–0·98)

55

0·48*
(0·35–0·65)

264

0·67*
(0·57–0·80)

Moderate

··

··

··

151

0·88
(0·72–1·07)

131

0·80*
(0·65–0·99)

63

0·76
(0·56–1·03)

35

0·47*
(0·33–0·69)

229

0·72*
(0·60–0·86)

Vigorous

··

··

··

3

0·90
(0·29–2·80)

10

0·38*
(0·17–0·86)

5

0·53(0·22–1·27)

20

0·49*
(0·30–0·78)

35

0·47*
(0·32–0·68)

Diabetes mellitus

··

358

1

117

0·89
(0·71–1·12)

110

0·77*
(0·61–0·97)

53

0·73
(0·52–1·01)

41

0·50*
(0·35–0·72)

204

0·69*
(0·57–0·84)

Moderate

··

··

··

113

0·88
(0·70–1·11)

101

0·78*
(0·61–0·99)

51

0·77
(0·55–1·08)

34

0·71
(0·49–1·04)

186

0·77*
(0·63–0·93)

Vigorous

··

··

··

4

1·60
(0·56–4·55)

90·66(0·31–1·40)

2

0·37(0·09–1·50)

7

0·12*
(0·04–0·38)

18

0·30*
(0·17–0·53)

All-cause mortality
for all individuals

StrokeHR=hazard ratio *Indicates a signiﬁcantly (p<0·05) lower death rate compared with the inactive group.

Table 3: Mortality risk, by exercise volume and intensity

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A All cause

B All cancer

1·00
0·90
0·80

Hazard ratio

0·70
0·60
0·50
0·40
0·30
0·20
0·10
0

C Cardiovascular disease

D Diabetes mellitus

1·00
0·90
0·80

Hazard ratio

0·70
0·60
0·50
0·40
0·30
0·20
0·10
0

Inactive

Low

MediumHigh

Very highInactive

Low

Activity level

MediumHigh

Very highActivity level

Figure 1: Relation between physical activity volume and mortality reduction compared with individuals in the inactive group
Bars show 95% CIs.

See Online for webappendix

1248

were assessed for all mortality outcomes, and werecorded no signiﬁcant interaction between any of them.
The 13 pre-speciﬁed confounders were age, sex,
education, physical labour at work, smoking, drinking,fasting blood glucose, systolic blood pressure, totalcholesterol, BMI, diabetes, hypertension, and history ofcancer. The life table method was used to estimate life
expectancy.6,14 We calculated adjusted odds ratios and
95% CIs (webappendix p 1) by comparing the proportionof individuals meeting activity recommendations withthe proportion of those who were inactive within eachcharacteristic group (eg, sex, age, etc).
Estimated national prevalence of physical activity in
Taiwan was validated against nationally representative datafrom the health interview survey.15 We tested the reliabilityof questionnaire data by examining the consistency or
the test-retest stability of participants’ answers with theSpearman’s correlation tested within a given period.
We assessed content validity of the questionnaire byexamining the relation between exercise volume andselected physiological characteristics related to physicalactivity, such as obesity (BMI), percent body fat or highdensity lipoprotein, and the ability to predict similarmortality outcome when the same volume activity wasrecorded by diﬀerent individuals.
All statistical tests were two-sided with the alpha levelset at 0·05. Analyses were done with SAS, version 9.2.

Role of funding source
The funding source had no role in study design, datacollection, data analysis, data interpretation, writing of
the report, or in the decision to submit the paper for
publication. All authors had full access to all the datain the study and CPW, JPMW, MKT, YCY, and XFW
had ﬁnal responsibility for the decision to submit
for publication.

Results
Table 1 shows the proportion of individuals in each LTPA
volume category and selected characteristics of all
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www.thelancet.com Vol 378 October 1, 201150

All-cause mortality reduction (%)

individuals in the cohort. Table 2 shows activity
characteristics (duration, intensity, volume, and energy
expenditure) for each LTPA volume category (webappendix p 2 shows mean activity characteristics by sex
and age groups).
Compared with individuals in the low-volume activity
group, those in the inactive group had a 17% increased
all-cause mortality risk (HR 1·17, 95% CI 1·10–1·24) andan 11% increased cancer mortality risk (1·11, 1·01–1·22;
webappendix p 4). Table 3 shows mortality risks forindividuals in all activity groups compared with those in
the inactive group (webappendix p 3 shows all-cause
mortality risks by subgroup). Of those who met thephysical activity recommendation (medium to very highvolume activity) and did moderate-intensity exercise, werecorded a dose-response relation to health outcome, inthat those who were most active had a reduced risk of allcause mortality (ﬁgure 1; table 3).
Figure 2 shows the relation between daily physicalactivity and reduction in all-cause mortality comparedwith individuals in the inactive group. After theminimum recommended 15 min a day of exercise, every
additional 15 min of daily exercise (up to 100 min a day,after which additional exercise gave no additional healthbeneﬁt) is expected to generate an additional reduction
of 4% (95% CI 2·5–7·0) all-cause and 1% (0·3–4·5) allcancer mortality.
Subgroup analysis for sex, age, and cardiovasculardisease risks showed that, when compared with individuals
in the inactive group, those in the low-volume activity
group had a lower risk of all-cause mortality, irrespectiveof their sex, age, or health status, or whether or not theysmoke, drink, or have cardiovascular disease risk
(ﬁgure 3; webappendix p 3).
Compared with individuals in the inactive group, allcancer mortality and incidence were signiﬁcantly lower inthose in the low-volume activity group and in those in all
three groups that met the physical recommendation
guidelines (table 4). Both all-cancer mortality and all-cancer
incidence decreased as the amount of exercise an individual
did increased (p<0·0001 for both trends). Compared withindividuals in the low-volume activity group, those in theinactive group had 11% increased all-cancer risks (HR 1·11,
95% CI 1·01–1·22; webappendix p 4).
Vigorous-intensity exercise yielded similar or greater
health beneﬁts in terms of all-cause mortality reduction
than did moderate-intensity exercise at the same volume ofactivity or at the next higher volume of activity (table 3).
The relation between mortality reduction (for all diﬀerent
causes of death analysed) and activity level was much thesame in a sensitivity analysis, which excluded individuals
with a history of cancer (n=4752) or cardiovascular disease(n=51 051), and those who died within 3 years of enrolment(n=2357; webappendix p 9).
Compared with individuals in the inactive group, at age
30 years, life expectancy for individuals in the low-volume
activity group was 2·55 years longer for men andVigorous
Moderate
Total

40
35%
29%

30
20%
20
14%
10

0
0

10

20

30

40
50
60
70
Daily physical activity duration (min)

80

90

100

110

Figure 2: Daily physical activity duration and all-cause mortality reduction
HR (95% CI)
Men

0·84 (0·78–0·90)

Women

0·90 (0·82–0·98)

Individuals aged 20–59 years

0·84 (0·77–0·92)

Individuals aged ≥60 years

0·88 (0·82–0·95)

Self-reported healthy individuals

0·88 (0·82–0·96)

Hypertensive individuals

0·85 (0·75–0·97)Pre-hypertensive individuals

0·87 (0·78–0·97)

Diabetic individuals

0·78 (0·66–0·95)

Pre-diabetes individuals

0·79 (0·66–0·95)

Smokers0·86 (0·77–0·95)

Regular drinkers

0·80 (0·69–0·93)

Obese individuals

0·83 (0·75–0·91)

Individuals with hypercholesterolaemia

0·84 (0·74–0·94)

Individuals with metabolic syndrome

0·84 (0·76–0·93)

Individuals with chronic kidney disease

0·87 (0·80–0·95)

Total cohort

0·86 (0·81–0·91)
0·6

0·7
0·8
0·9
1·0
Eﬀect of exercise (p<0·05)
Favours low-volume activity

1·1

Favours inactive

Figure 3: Adjusted all-cause mortality hazard ratio for individuals in the low-volume activity group comparedwith individuals in the inactive group, by participant characteristic
All hazard ratios (HR) are relative to health outcomes in individuals in the inactive group.

3·10 years longer for women, and life expectancy in those
who met the recommended amount of daily exercise was
4·21 years longer for men and 3·67 years longer for
women (webappendix p 10).

Discussion
Individuals who did a daily average of 15 min of moderateintensity exercise had signiﬁcant health beneﬁts whencompared with individuals who were inactive. In Taiwan,
if inactive individuals engage in low-volume daily exercise,
one in six all-cause deaths could be postponed—mortality
reductions of similar magnitude have been estimated fora successful tobacco control programme in the general
population.16 The minimum amount of exercise reported
in this study is half of that recommended worldwide,1 but
individuals are more likely to do 15 min of daily exercise
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Total
cohortInactive

N

n

Low
HR§

n

Physical activity meeting recommendation
HR (95% CI)

MediumHigh

p for trend
Very high

Total

n

HR (95% CI)nHR (95% CI)nHR (95% CI)nHR (95% CI)

Cancer mortality
All cancer

4272

2185

1

755

0·90*
(0·83–0·99)

659

0·85*
(0·77–0·93)

318

0·85*
(0·75–0·97)

355

0·78*
(0·69–0·88)

1332

0·83*
(0·77–0·90)<0·0001

Colon andrectum cancer

421

201

1

86

1·08
(0·83–1·41)

63

0·71*
(0·52–0·96)

33

0·84
(0·56–1·25)

38

0·77
(0·53–1·12)

134

0·75*
(0·58–0·95)

0·039

Liver cancer

924

485

1

166

0·97
(0·80–1·18)

142

0·92
(0·75–1·12)

65

0·80
(0·60–1·07)

66

0·65*
(0·49–0·86)

273

0·82*
(0·69–0·98)

0·004

Lung cancer

917

490

1

129

0·73*
(0·59–0·90)

156

0·93
(0·77–1·14)

61

0·78
(0·59–1·04)

81

0·79
(0·61–1·02)

298

0·85*
(0·72–0·99)

0·031

Breast cancer

179

90

1

36

0·99
(0·64–1·52)

30

1·40
(0·89–2·21)

17

1·73
(0·96–3·11)

6

0·86(0·37–2·01)

53

1·37
(0·94–2·03)

0·229

11 802

6015

1

2233

0·94*
(0·89–0·99)

1781

0·87*
(0·82–0·92)

787

0·86*
(0·79–0·93)

986

0·93
(0·86–1·00)

3554

0·88*
(0·84–0·93)<0·0001

Colon andrectum cancer

1509

713

1

300

1·02
(0·88–1·19)

234

0·86
(0·73–1·02)

108

0·84
(0·67–1·06)

154

1·04
(0·86–1·26)

496

0·91
(0·79–1·03)

0·406

Liver cancer

1676

890

1

305

0·95
(0·82–1·10)

247

0·85*
(0·73–1·00)

116

0·87
(0·70–1·08)

118

0·70*
(0·56–0·86)

481

0·81*
(0·71–0·92)

0·004Lung cancer

1266

650

1

195

0·83*
(0·69–0·99)

204

0·98
(0·83–1·17)

84

0·87
(0·68–1·12)

133

1·12
(0·91–1·37)

421

1·00
(0·87–1·15)

0·626

Breast cancer

1364

760

1

299

0·95
(0·82–1·10)

173

0·88
(0·73–1·06)

82

1·13
(0·88–1·45)

50

0·79
(0·58–1·09)

305

0·92
(0·79–1·07)

0·304

Breast cancer(age >50 years)

540

262

1

106

0·89
(0·69–1·14)

95

0·89
(0·69–1·16)

42

0·93
(0·65–1·33)

35

0·86
(0·59–1·24)

172

0·89
(0·72–1·11)

0·330

Cancer incidence
All cancer

Hazard ratios (HR) for mortality are adjusted for age, sex, education, activity at work, smoking, drinking, fasting blood glucose, systolic blood pressure, body mass index, diabetes history, and hypertension history.
HR calculations for cancer incidences exclude individuals with a history of cancer before they entered the cohort. *Indicates a signiﬁcantly (p<0·05) lower incidence or mortality rate compared with the inactive group.

Table 4: Hazard ratios for cancer mortality and incidence, by volume of leisure-time physical activity

than they are 30 min of daily exercise. Furthermore, once
an individual does 15 min of daily exercise regularly, theymight be more likely to increase the amount of time they
spend exercising per day, possibly leading to a change inthe social norm by increasing the amount of LTPA done ina largely inactive society. With this potential increase in
exercise in mind, a recommendation of 15 min of daily
exercise should be promoted to east Asian populations.
Although the reduction of all-cause mortality with
exercise is an important focus for health communication
messages, the reduction in cancer risk with exercise isequally important. Such cancer-related messages can bea powerful motivation for Asians to exercise because
cancer is by far the leading cause of death in thispopulation.8,17 Our results suggest that one in nine deaths
from cancer in individuals in the inactive group could
have been averted if they did 15 min of moderate-intesity
daily exercise. We know of no other studies to report
protection against all cancer from a dose below therecommended 30 min a day,18 or the graded doseresponse relation of moderate intensity LTPA (panel).1,2,19
The relation between exercise and reductions infrequency of site-speciﬁc cancers was less consistentthan it was for all cancers, however, for reasons that havenot been explored.19,20
1250

The magnitude of all-cause mortality reduction from15 min a day exercise was consistent in men and womenacross all age groups (webappendix pp 5–8), with results
much the same after controlling for 13 confounders. Theseﬁndings, particularly in individuals with cardiovasculardisease risk, have important implications for clinicalpractice. Such people can beneﬁt substantially fromincorporating this low level of exercise into their treatment
modalities. The universal nature of this advice for inactive
individuals would greatly reduce the need to individualise
an exercise prescription on the basis of an individual’s
physical capability.21
Health gains achieved below the recommended level
have been reported,22,23 but a minimum dose for life
prolongation has not been identiﬁed. Endpoints in somestudies focused more on disease incidence22–28 than they
did on mortality,25,29–32 and focused largely on elderly
women.22,23,26,29,33 Furthermore, many studies were unable toquantify the beneﬁts of moderate-intensity exercise
because they included individuals who did some vigorousintensity exercise.24,30,32
The reason why the small amounts of LTPA provided
signiﬁcant health beneﬁts needs further discussion. First,
the dose-response gradient between exercise time andmortality beneﬁts was not linear but curvilinear (ﬁgure 2),
www.thelancet.com Vol 378 October 1, 2011

Articleswith the largest health gains from the ﬁrst
1–2 h of exercise a week. This curvilinear relation between
exercise and health gains has been reported in otherstudies.1,2,34,35 Second, mortality reduction at an exercise
volume less than the recommended 150 min a week has
also been recorded elsewhere,24–26,29–32 but these other studies
were unable to identify a threshold volume of exercise atwhich health gains were achieved. When sample size
limitations were overcome in pooled studies or metaanalyses, statistically signiﬁcant health beneﬁts of aminimum amount of exercise have been recorded.34–36
Third, half our cohort self-reported as being inactive, which
is more than double the number of people who did so in
the USA (23·7%),37 implying that the habit of regularexercise is far from being adopted as the social norm ineast Asia. As the Taiwanese population has become
wealthier, they have done less manual labour and haveincreased their use of motor vehicles for transportation—
Taiwan has the greatest density of motorcycles in theworld.38 Against this backdrop of an inactive majority as areference population, low-volume exercise as deﬁned inthis study is not actually very low because such exercise
needs to be done for most days of the week for many years.
Fourth, individuals in all three activity groups that met thephysical activity recommendation and those who engaged
in low-volume activity had fewer health risks (eg, diabetes,smoking, or obesity) compared with individuals in theinactive group. This ﬁnding is intriguing because
diﬀerences in risk factors were controlled in our adjustment
process, and, therefore, health beneﬁts recorded in these
individuals were probably attributable to their physicaleﬀort and not to the lower prevalence of risk factors.
Although physical activity alone can improve health,increasing physical activity can indirectly improve healthby decreasing other health risks (eg, lifestyle risks) that areassociated with inactivity.5,39 The fact that ex-smokers
exercised more than smokers suggests that physical activity
might have helped smokers to quit. In this way, exercisers
might be more likely to quit smoking, lose weight, or
reduce their chances of developing diabetes.5,39 Fifth, thepsychological eﬀect of walking to work and walking as aleisure activity diﬀer. Only leisure-time walking, when
done regularly, has been hypothesised to release
endorphins,40 the release of which, even in small amounts,
can be associated with mental wellbeing.41 Such wellbeing
can help in the prevention and management of cardiovascular disease.42
Vigorous-intensity activities are usually associated witha larger volume of exercise than are moderate-intensity
activities, and therefore oﬀer greater health beneﬁts.2,34
We know of no other studies that have shown theadvantages of vigorous-intensity activities over moderateintensity activities at an identical volume or the next
higher volume of activity. Our ﬁndings suggest that, forexample, 2 h a week of vigorous-intensity exercise could
generate similar health beneﬁts as would 4 h a week ofmoderate-intensity exercise. Therefore, people who want
www.thelancet.com Vol 378 October 1, 2011

Panel: Research in context
Systematic review
We searched PubMed, Medline, and Google Scholar with the search terms “leisure-time
physical activity”, “exercise”, “dose-response”, “intensity”, and “mortality”. We also
searched the reference lists of relevant papers identiﬁed. Cohort studies on leisure-time
physical activity (LTPA) that recorded signiﬁcant health beneﬁts, particularly fromall-cause mortality, without meeting the 150 min per week recommendation, were given
preference. Of 12 studies identiﬁed (webappendix p 11), three reported reduction in
occurrence of cardiovascular disease or diabetes, mostly in women aged 50–79 years. In
the nine studies of mortality, identiﬁcation of a minimum amount of exercise was notpossible, because they either included vigorous-intensity exercise components orindividuals who exercised more than the recommended level.
Interpretation
In this study, 15 min a day or 90 min a week provided a reduction in all-cause and all-cancer
mortality and extended an individual’s lifespan for an average of 3 years. This minimum
amount of exercise is applicable to men and women of all ages, even those withcardiovascular diseases or lifestyle risks. Use of this exercise recommendation in clinicalpractice could help most patients to become more active and, ultimately, healthier.

to exercise but claim not to have much available time canbeneﬁt from the positive health eﬀects of exercise if they
do vigorous-intensity exercise once or even twice a week(eg, at weekends). Although such people—termed
weekend warriors elsewhere43—could achieve signiﬁcanthealth beneﬁts and should not be discouraged, they are
not to be encouraged, either, because of the potential forincreased injury and cardiovascular risks.
Reliability of our questionnaire, measured byconsistency in answers given on consecutive visits, isimportant because it aﬀects the quality of our ﬁndings.
Reliability of our questionnaire was much the same asthat of other questionnaires that are widely accepted asreliable.2 We compared outcomes in individuals who
made at least two visits and were consistent in theirreporting of exercise volumes. Compared with individuals
in the inactive group, individuals in the low-volume
exercise group had HRs for all-cause mortalityof 0·86 (95% CI 0·77–0·98) on their ﬁrst visit
and 0·90 (0·80–1·02) on their second visit, and individuals
who met or exceeded the 2008 recommendations had
HRs for all-cause mortality of 0·74 (0·60–0·92) on theirﬁrst visit and 0·79 (0·72–0·87) on their second visits,
which were suﬃciently close to make the validity of ourquestionnaire within an acceptable range.
One of the strengths of this study is the expression of
the beneﬁts of LTPA in both mortality reduction andextension of life. Life expectancy, not presented in moststudies, can be calculated only when the study population
is suﬃciently large. Health messages in terms of life
extension are easy to understand and can motivate
inactive individuals to take up exercise.44
This study had several limitations. First, because thiswas an observational study, we cannot attribute therecorded health outcomes entirely to physical activity.
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Although healthier individuals tend to exercise more, ourﬁndings show that individuals who were less healthy—
those with risk factors or with cardiovascular diseases—
had improvement in health when they did exercise above
the 15 min daily amount. Second, people have a tendency
to over-report LTPA because it is a socially desirable
behaviour.45 However, such over-reporting of LTPA would
bias the ﬁndings in support of a null hypothesis. Third,
results from this cohort, who were recruited fromparticipants with above average socioeconomic status,
might not be generalisable to all east Asians, and the
proportion of individuals who are inactive could be anunderestimate. Nevertheless, the risks calculated for HRs,
internally standardised with socioeconomic status adjusted,should be valid estimates. Fourth, of the four domains ofphysical activity (work, transportation, household, andLTPA), only leisure-time activity was studied. However, of
these four domains, LTPA is the most related with healthbeneﬁts.41 Furthermore, only LTPA is eﬀort-related andpromotable. Fifth, the validity of HRs depends on thecompleteness of follow-up. Because Taiwan has a national
death ﬁle that records all deaths, we believe that few
individuals were lost to follow-up. Results from the deathﬁle data were very similar to those from the cancer registry,
which is a diﬀerent set of national data supported withlaboratory conﬁrmation.
If the minimum amount of exercise we suggest isadhered to, mortality from heart disease, diabetes, andcancer could be reduced. This low-volume of physicalactivity could play a central part in the global war against
non-communicable diseases,46,47 reducing medical costs
and health disparities.
Contributors
CPW and JPMW had the idea for and designed the study. JPMW
developed the analytical methodology on leisure-time physical activity. SPT
and YCY developed the analytical methodology on life expectancy. CPW,
JPMW, SPT, M-CL, MKT, YCY, and HTC analysed and interpreted the data.
CPW and JPMW drafted the article and submitted the paper for
publication. CPW, JPMW, M-CL, YCY, and XFW critically revised thearticle for important intellectual content. CPW, JPMW, MKT, and YCY had
ﬁnal approval of the article. CKT provided study materials and was
responsible for quality control of data from the leisure-time physicalactivity questionnaire. SPT, MKT, YCY, HTC, and TYDC provided
statistical expertise. MKT, YCY, and HTC provided administrative,
technical, or logistical support. CKT was responsible for collection andassembly of data.

2

3

4

5

6

7
8

9

10

11

12

13

14
15

16

17

18

19

Conﬂicts of interest
We declare that we have no conﬂicts of interest.
Acknowledgments
We thank MJ Health Management Institution for making their large
dataset available to us. We thank Nelson Wen for his help in revising theEnglish in this manuscript. This study was supported by Taiwan
Department of Health Clinical Trial and Research Centre of Excellence(DOH 100-TD-B-111-004) and the institutional support from National
Health Research Institutes.
References
1
Physical Activity Guidelines Advisory Committee. Physical activity
guidelines advisory committee report and 2008 physical activity
guidelines for Americans. http://www.health.gov/paguidelines/
committeereport.aspx and http://www.health.gov/paguidelines/pdf/
paguide.pdf (accessed March 9, 2011).

1252

20

21

22

23

Lee I-M, Blair S, Manson J, Paﬀenbarger RS. Epidemiologic
methods in physical activity studies, 1st edn. New York: Oxford
University Press, 2009.
WHO. Global Recommendations on physical activity for health.
http://www.who.int/dietphysicalactivity/factsheet_recommendations/en/index.html (accessed May 20, 2011).
Ku P-W, Fox KR, McKenna J, Peng T-L. Prevalence of leisure-time
physical activity in Taiwanese adults: results of four national
surveys, 2000–2004. Prev Med 2006; 43: 454–57.
Wai JPM, Wen CP, Chan HT, et al. Assessing physical activity inan Asian country: low energy expenditure and exercise frequency
among adults in Taiwan. Asia Pac J Clin Nutr 2008; 17: 297–308.
Wen CP, Tsai SP, Chung W-SI. A 10-year experience with universal
health insurance in Taiwan: measuring changes in health andhealth disparity. Ann Intern Med 2008; 148: 258–67.
Warburton DER, Nicol CW, Bredin SSD. Prescribing exercise as
preventive therapy. CMAJ 2006; 174: 961–74.
Department of Health Executive Yuan Taiwan. National death ﬁleand national cancer registry ﬁle. http://www.doh.gov.tw/
CHT2006/DM/DM2_2_p02.aspx?class_no=440&now_fod_list_
no=11668&level_no=5&doc_no=78419 and http://cph.ntu.edu.tw/
main.php?Page=A5#t01 (accessed March 2, 2011).
Carlson SA, Densmore D, Fulton JE, Yore MM, Kohl HW.
Diﬀerences in physical activity prevalence and trends from
3 US surveillance systems: NHIS, NHANES, and BRFSS.
J Phys Act Health 2009; 6: S18–S27.
Wen CP, Cheng TYD, Tsai SP, et al. Are Asians at greater mortality
risks for being overweight than Caucasians? Redeﬁning obesity for
Asians. Public Health Nutr 2008; 12: 497–506.
National Institutes of Health. National Cholesterol Education
Program (NCEP) expert panel on detection, evaluation, andtreatment of high blood cholesterol in adults (Adult Treatment
Panel III) ﬁnal report. Circulation 2002; 106: 3143–421.
K/DOQI clinical practice guidelines for chronic kidney disease:evaluation, classiﬁcation, and stratiﬁcation. Am J Kidney Dis 2002;
39: s1–s266.
Wen CP, Cheng TYD, Tsai MK, et al. All-cause mortality
attributable to chronic kidney disease: a prospective cohort
study based on 462,293 adults in Taiwan. Lancet 2008;
371: 2173–82.
Chiang CL. The life table and its applications. Malabar, FL: RE
Krieger Pub Co, 1984.
National Health Research Institutes. National Health Interview
Survey (NHIS) in 2005: Bureau of Health Promotion and National
Health Research Institutes 2005. http://nhis.nhri.org.tw (accessed
May 3, 2011).
Wen CP, Tsai SP, Chen CJ, Cheng TY, Tsai MC, Levy DT. Smoking
attributable mortality for Taiwan and its projection to 2020 underdiﬀerent smoking scenarios. Tobacco Control 2005;
14(suppl 1): i76–80.
Foundation for Promotion of Cancer Research (FPCR). Cancer
statistics in Japan 2010. Tokyo: Foundation for Promotion of Cancer
Research, 2008.
Friedenreich CM, Orenstein MR. Physical activity and cancer
prevention: etiologic evidence and biological mechanisms. J Nutr
2002; 132: 3456S–64S.
World Cancer Research Fund and American Institute for Cancer
Research. Food, nutrition, physical activity, and the prevention ofcancer: a global perspective. Washington DC: American Institutefor Cancer Research, 2007.
Thune I, Furberg A-S. Physical activity and cancer risk:
dose-response and cancer, all sites and site-speciﬁc.
Med Sci Sports Exerc 2001; 33: S530–50.
American College of Sports Medicine. ACSM’s guidelines forexercise testing and prescription, 6th edn. USA: Lippincott
Williams and Wilkins, 2000.
Lee I-M, Rexrode KM, Cook NR, Manson JE, Buring JE. Physicalactivity and coronary heart disease in women—is no pain, no gain
passe? JAMA 2001; 285: 1447–54.
Manson JE, Greenland P, LaCroix AZ, et al. Walking compared withvigorous exercise for the prevention of cardiovascular events inwomen. N Engl J Med 2002; 347: 716–25.

www.thelancet.com Vol 378 October 1, 2011

Articles

24

25

26

27

28

29

30

31

32

33

34

35

Bijnen FCH, Caspersen CJ, Feskens EJM, Saris WHM,
Mosterd WL, Kromhout D. Physical activity and 10-year mortality
from cardiovascular diseases and all causes. Arch Intern Med 1998;
158: 1499–505.
Gregg EW, Gerzoﬀ RB, Caspersen CJ, Williamson DF, Narayan KM.
Relationship of walking to mortality among US adults withdiabetes. Arch Intern Med 2003; 163: 1440–47.
Rockhill B, Willett WC, Manson JE, et al. Physical activity andmortality: a prospective study among women. Am J Public Health
2001; 91: 578–83.
Tanasescu M, Leitzmann MF, Rimm EB, Hu FB. Physical activity
in relation to cardiovascular disease and total mortality among men
with type 2 diabetes. Circulation 2003; 107: 2435–39.
Wisloﬀ U, Nilsen TIL, Droyvold WB, Morkved S, Slordahl SA,
Vatten LJ. A single weekly bout of exercise may reduce
cardiovascular mortality: how little pain for cardiac gain?
The HUNT study, Norway. Eur J Cardiovasc Prev Rehabil 2006;
13: 798–804.
Kushi LH, Fee RM, Folsom AR, Mink PJ, Anderson KE, Sellers TA.
Physical activity and mortality in postmenopausal women. JAMA
1997; 277: 1287–92.
Leitzmann MF, Park Y, Blair A, et al. Physical activity
recommendations and decreased risk of mortality. Arch Intern Med
2007; 167: 2453–60.
Schnohr P, Scharling H, Jensen JS. Intensity versus duration ofwalking, impact on mortality: the Copenhagen City Heart Study.
Eur J Cardiovasc Prev Rehabil 2007; 14: 72–78.
Schooling CM, Lam TH, Li ZB, et al. Obesity, physical activity, andmortality in a prospective Chinese elderly cohort. Arch Intern Med
2006; 166: 1498–504.
Hu FB, Sigal RJ, Rich-Edwards JW, et al. Walking compared withvigorous physical activity and risk of type 2 diabetes in women.
JAMA 1999; 282: 1433–39.
Lollgen H, Bockenhoﬀ A, Knapp G. Physical activity and all-cause
mortality: an updated meta-analysis with diﬀerent intensity
categories. Int J Sports Med 2009; 30: 213–24.
Woodcock J, Franco OH, Orsini N, Roberts I. Non-vigorous physicalactivity and all-cause mortality: systematic review and meta-analysis
of cohort studies. Int J Epidemiol 2010; 40: 121–38.

www.thelancet.com Vol 378 October 1, 2011

36

37

38

39

40

41

42
43
44

45

46

47

Sattelmair J, Pertman J, Ding EL, et al. Dose response between
physical activity and risk of coronary heart disease: a meta-analysis.
Circulation 2011; 124: 789–95.
US CDC. Trends in leisure-time physical inactivity by age, sex, andrace/ethnicity—United States, 1994–2004. MMWR Morb Mortal
Wkly Rep 2005; 54: 991–94.
Chung W-SI, Tsai SP, Tsai MK, Wen CP. Analysis of the associationof urban/rural gap between motor vehicle accidents and life
expectancy in Taiwan. Taiwan J Public Health 2010; 29: 261–72.
Carlsson S, Andersson T, Wolk A, Ahlbom A. Low physical activity
and mortality in women: baseline lifestyle and health as alternative
explanations. Scand J Public Health 2006; 34: 480–87.
Boecker H, Sprenger T, Spilker ME, et al. The runner’s high:opioidergic mechanisms in the human brain. Cereb Cortex 2008;
18: 2523–31.
Cerin E, Leslie E, Sugiyama T, Owen N. Associations of multiple
physical activity domains with mental well-being.
Ment Health Phys Act 2009; 2: 55–64.
Warburton DER, Nicol CW, Bredin SSD. Health beneﬁts of physicalactivity: the evidence. CMAJ 2006; 174: 801–09.
Lee I-M, Sesso HD, Oguma Y, Paﬀenbarger RS. The “Weekend
Warrior” and risk of mortality. Am J Epidemiol 2004; 160: 636–41.
Ziegelmann JP, Lippke S, Schwarzer R. Subjective residual life
expectancy in health self-regulation. J Gerontol B Psychol Sci Soc Sci
2006; 61: P195–P201.
Adams SA, Matthews CE, Ebbeling CB, et al. The eﬀect of social
desirability and social approval on self-reports of physical activity.
Am J Epidemiol 2005; 161: 389–98.
Beaglehole R, Bonita R, Alleyne G, et al. UN High-Level Meetingon Non-Communicable Diseases: addressing four questions.
Lancet 2011; 378: 449–55.
Global Advocacy for Physical Activity. The Toronto Charter for
Physical Activity: a global call for action. http://www.globalpa.org.uk(accessed June 20, 2011).

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