Clinical trial NCT01722136: "We Walk": Impact of Exercise Dose on Health Outcomes Among Women Ages 60-75
Official title: We Walk - Energy Expenditure and Health Outcomes in Older, Sedentary Women.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Condition
Lead sponsor: University of South Carolina
Sponsor class: OTHER
First posted: 2012-11-06
Enrollment: 72
Sex: FEMALE
Minimum age (years): 60
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: SUPPORTIVE_CARE

Brief summary: The overall goal is to determine whether any energy expenditure compensation in response to 16 weeks of aerobic exercise at a higher-dose is greater compared to a lower-dose intervention in older women, and to begin to investigate underlying physiological mechanisms that influence energy expenditure changes in older women.

Detailed description: The overall goal is to determine whether any energy expenditure compensation in response to 16 weeks of aerobic exercise at a higher-dose is greater compared to a lower-dose intervention in older women, and to begin to investigate underlying physiological mechanisms that influence energy expenditure changes in older women. Changes in all components of energy expenditure, as well as concentrations of plasma leptin and serum free T3, in response to the two different exercise programs (14 and 8 kcal/kg body weight weekly, 60-65% VO2max, 4 days/wk) will be compared in older, non-obese women (60-75 yrs, BMI=18-30 kg/m2).

Specific Aim 1: To determine whether differential changes in total daily energy expenditure and its components occur in older women in response to two exercise programs of different doses. State-of-the-art methods will be used (total daily energy expenditure by doubly labeled water; non-exercise activity thermogenesis using Physical Activity Monitoring System; resting metabolic rate and thermic effect of food via indirect calorimetry).

Primary Hypothesis: Due to a greater decline in NEAT, women will exhibit a smaller increase in total daily energy expenditure in response to the higher-dose, compared to the lower-dose, exercise program, despite greater increases in resting metabolic rate and thermic effect of food.

Specific Aim 2: To explore whether differential changes occur in plasma leptin and serum free triiodo-L-thyronine (free T3) concentrations in older women in response to 16-week aerobic exercise programs of two different doses.

We hypothesize that in response to the higher-dose exercise program, women will exhibit larger decreases in plasma leptin and serum free T3 concentrations, compared to the lower-dose exercise program.

We will also determine whether women exhibit greater improvements in plasma lipids, insulin sensitivity (using homeostasis model assessment, HOMA, score), blood pressure, and aerobic fitness in response to the higher-dose, compared to the lower-dose, exercise program.

Eligibility criteria: Inclusion Criteria:

* BMI 18-30
* Sedentary (exercising less than 20 minutes no more than 3 times per week)
* Non-smoking
* Weight stable (+/- 5%) over past 3 months

Exclusion Criteria:

* Self-reported cardiovascular disease
* Additional self-reported medical conditions
* Medications known to affect metabolism
* Excess caffeine use
* Self-reported contradictions according to ACSM
* Unwillingness to provide informed consent

Primary outcomes:
measure: Change from baseline total daily energy expenditure and its components (resting metabolic rate, thermic effect of food, non-exercise activity thermogenesis)in 4 months
timeFrame: Baseline (pre-intervention); 4 months (post-intervention)
Secondary outcomes:
measure: Change from baseline plasma leptin and serum free triiodo-L-thyronine (free T3) concentrations in 4 months
timeFrame: Baseline (pre-intervention); 4 month (post-intervention)
Other outcomes:
Locations:
city: Columbia
country: United States
facility: Public Health Research Center University of South Carolina
state: South Carolina
Study officials:
affiliation: University of South Carolina
name: Xuewen Wang, PhD, MEd, BM
role: PRINCIPAL_INVESTIGATOR
References: