Postmenopausal Metabolic Health
Conditions
Keywords
basal metabolic rate, resting energy expenditure, menopause, physical activity, metabolic syndrome
Brief summary
The primary purpose of this study is to expand research on the effects of physical activity on basal metabolic rate (BMR) in healthy postmenopausal women, and to further compare the effects of long-term habitual exercise to the results of a shorter-term (16 weeks) training program. The investigators will measure BMR by indirect calorimetry and normalize it across subjects for body size (fat free mass) and level of aerobic fitness (VO2MAX). Two groups will be compared: an intervention group (no previous participation in regular exercise, newly enrolled in this study's 16 week training program), and a long-term athlete group (have engaged in at least 5 hours of exercise per week for the past 10 years or longer). A secondary aim is to generate an equation for the prediction of BMR from fat free mass in physically active postmenopausal women, to be applied to hypotheses in biological anthropology. The investigators expect to find at baseline that, controlling for fat free mass and VO2MAX, the long-term group will have significantly higher BMR than the intervention group. At 16 weeks the investigators expect no change in BMR for the long-term group, while BMR will have increased in the intervention group. At the same time, the investigators expect to find that after completing the training regimen, the intervention group will have BMR similar to that of the long-term athletes.
Interventions
BEHAVIORALResistance and aerobic exercise
Following baseline measurements, sedentary women were enrolled in a 16-week exercise training program at the YMCA in La Jolla, CA. Exercise occurred 3 times per week, for 1.5 hours each time. Exercise consisted of stretching, 20 minutes of aerobic exercise on elliptical machines, and 3 sets of 10-12 repetitions to failure for each of ten weight lifting exercises: abdominal crunch, arm curl, arm extension, chest press, lat pull-down, leg curl, leg extension, leg press, seated row, and trunk extension. Women started at 65-75% of 1-repetition-maximum, and resistance was increased as necessary to maintain the number of sets and reps and to continue to work to failure. Exercise was monitored by a TechnoGym electronic key system, and trainers instructed and supervised subjects in the gym.
Sponsors
Wenner Gren
Sigma Xi
National Center for Research Resources (NCRR)
University of California, San Diego
Study design
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
40 Years to 120 Years
Healthy volunteers
Yes
Inclusion criteria
* naturally postmenopausal (i.e. non-surgically)/\> 1 year since last menstruation * FSH \> 30 mIU/ml * estradiol-17β \< 25 pg/ml
Exclusion criteria
* smoker, abuser of alcohol/other drugs * hypo- or hyperthyroid (serum TSH \< 0.3 or \> 5.5 microU/ml, respectively) * underweight or severely obese (BMI \< 18.5 or \> 35 kg/m2, respectively) * weight instability within the past six months (±\> 5% of body weight) * hormone replacement therapy within the past six months * history of metabolic, respiratory or cardiovascular disease * high blood pressure * contraindication for maximal aerobic testing as determined by PAR-Q questionnaire and physician's examination
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in basal metabolic rate | baseline, 5, 10 and 16 weeks | Basal metabolic rate is the energy expended at rest and under fasting conditions. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in fat-free mass | baseline, 5, 10 and 16 weeks | — |
| Change in maximal aerobic capacity | baseline, 16 weeks | The maximal oxygen consumption achieved during a graded exercise test to exhaustion. Equipment: electronically-braked cycle ergometer. Participants were screened for CVD risk prior to testing by a physician. Lead II EKG was monitored during testing, and each test was overseen by a physician. |
Countries
United States
Outcome results
None listed