Physical Activity and Basal Metabolic Rate in Postmenopausal Women

University of California San Diego

Status: Completed

Conditions: Postmenopausal Metabolic Health

Treatments: Behavioral: Resistance and aerobic exercise

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT01550536

5M01RR000827-35 (U.S. NIH Grant/Contract)

UCSD GCRC 1910/6766

Details and patient eligibility

About

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.

Enrollment: 49 patients

Sex: Female

Ages: 40 to 120 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Parallel Assignment

Masking: None (Open label)

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49 participants in 2 patient groups

Training

Experimental group

Description:

Sedentary women who exercised \<2 hours per week and who had never engaged in a regular exercise program were enrolled in an exercise training intervention, following baseline measurements. See intervention below.

Treatment:

Behavioral: Resistance and aerobic exercise

Active

No Intervention group

Description:

Postmenopausal women who exercised \>5 hours per week and had been doing so for at least the past 10 years. These women were asked to maintain their normal activity habits for the duration of the study.