"We Walk": Impact of Exercise Dose on Health Outcomes Among Women Ages 60-75 (WW)

We Walk - Energy Expenditure and Health Outcomes in Older, Sedentary Women.

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.

Study Overview

• Status: Completed
• Conditions: Condition
• Intervention / Treatment: Behavioral: Low Dosage; Behavioral: High Dosage

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.

• Study Type: Interventional
• Enrollment (Actual): 72
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • South Carolina
    • Columbia, South Carolina, United States, 29201
      • Public Health Research Center University of South Carolina

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 60 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Low Dosage; Exercise dose of 8kcal/kg/week	Behavioral: Low Dosage; Exercise dose of 8kcal/kg/week
Experimental: High Dosage; Exercise dose 14kcal/kg/week	Behavioral: High Dosage; Exercise dose of 14kcal/kg/week

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change from baseline total daily energy expenditure and its components (resting metabolic rate, thermic effect of food, non-exercise activity thermogenesis)in 4 months	Baseline (pre-intervention); 4 months (post-intervention)

Secondary Outcome Measures

Outcome Measure	Time Frame
Change from baseline plasma leptin and serum free triiodo-L-thyronine (free T3) concentrations in 4 months	Baseline (pre-intervention); 4 month (post-intervention)

Collaborators and Investigators

• Sponsor: University of South Carolina
• Investigators: Principal Investigator: Xuewen Wang, PhD, MEd, BM, University of South Carolina

Publications and helpful links

Helpful Links

• Brief description of study for potential participants

Study record dates

Study Major Dates

• Study Start: August 1, 2012
• Primary Completion (Actual): June 1, 2015
• Study Completion (Actual): June 1, 2015

Study Registration Dates

• First Submitted: October 24, 2012
• First Submitted That Met QC Criteria: November 2, 2012
• First Posted (Estimate): November 6, 2012

Study Record Updates

• Last Update Posted (Actual): April 19, 2019
• Last Update Submitted That Met QC Criteria: April 17, 2019
• Last Verified: May 1, 2016

More Information

Terms related to this study

• Other Study ID Numbers: Pro00016306