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Birth Control Pill Impairs Muscle Gain

Posted on 20 April 2009 by admin

The latest headline about the birth control pill is about how it hinders women’s ability to build muscle.

According to researchers at Texas A&M University and University of Pittsburgh women who take oral contraceptives (OC) will find any muscle which might be gained from resistance exercise training is impaired.

The researchers from Texas A&M and the University of Pittsburgh say they have identified a potential new factor that may be independently associated with the characteristics and variability of muscle responses to a controlled resistance exercise training program.
For the study, 73 generally healthy women between the ages of 18-31 were assigned to two groups and completed a 10-week whole-body resistance exercise training (RET).
Group 1 consisted of 34 women who used oral contraceptives (OC). Group 2 consisted of 39 women who did not take birth control pills (non-OC).

The women were encouraged to consume at least 0.5 grams of protein per pound of body weight per day (a third more than is called for by the U.S. government nutritional guidelines) to make sure they consumed enough calories and protein to promote muscle growth.

muscle_chartThe participants exercised three times per week for ten weeks under the supervision of exercise physiologists. They performed a variety of exercises to include chest press, lat pull down, leg extension, triceps extension, arm curl and abdominal crunch.

Exercise was done using standard exercise machines and each volunteer performed three sets of 6-10 repetitions per exercise at 75 percent of their maximum strength. Body composition was determined using hydrostatic weighing.

Blood samples were taken before and after the training and assessed to measure anabolic (muscle building) and catabolic (muscle breaking) hormone levels in blood. Resting and fasting blood concentrations were measured for three anabolic hormones: DHEA, DHEAS and IGF1.

Women not taking oral contraceptives gained more than 60 percent more muscle mass than those on the pill.

There were other changes noted in participants on the pill, including reduced concentrations of the hormone DHEA, which Lee explained, is an anabolic hormone and therefore builds muscle.

The team presented their findings at the American Physiological Society meeting, part of the Experimental Biology 2009 scientific conference currently underway in New Orleans.

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