Pumping iron while taking the pill may lower muscle gains

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Ladies: Are you pumping iron and feeling the burn but not seeing much muscle gain? Your birth control pills might be to blame.

A recent study found that oral contraceptives may trigger lower hormone levels, in turn affecting muscle building. The study included 73 women ages 18 to 31 who were divided into two groups -- one taking oral contraceptives and one not taking them. Each group finished 10 weeks of resistance training exercises supervised by exercise physiologists, and workouts included chest presses, lat pull-downs, leg extensions, arm curls and crunches. The participants also were asked to eat at least half a gram of protein per pound of body weight a day to ensure they were getting enough protein and calories to initiate muscle growth.

Before and after training, blood samples were taken to determine levels of anabolic and catabolic hormone levels. Anabolic hormones influence muscle growth, while catabolic hormones, such as cortisol, can destroy muscle fibers.

Women not taking birth control pills added more than 60% more muscle mass than women who were taking the drugs. Also, fasting levels of anabolic hormones were lower and plasma concentrations of cortisol were higher in the contraceptive group than the non-contraceptive group. However, gains in strength and arm and leg circumferences were about the same in both groups.

The study, done by researchers at Texas A&M University and the University of Pittsburgh, was presented recently at the annual meeting of the American Physiological Society.

-- Jeannine Stein