Women Using Birth Control Pill Develop Less Muscle Mass
According to a new study, women who use birth control pills have less of a chance at developing muscle mass from resistance training. The study is the first to examine the effects of oral contraceptive hormone use and muscle gain.
Oral contraceptive use was associated with higher cortisol levels among women age 18-31 during an exercise training program The pill was also shown to lower levels of anabolic hormones, necessary for building muscle among the women studied.
Scientists from Texas A&M and University of Pittsburgh studied 73 women who engaged in 10-week whole-body resistance exercise training program. Two groups were assigned: one group consisting of 34 women who used the pill and a comparison group of 39 women who did not use contraceptive hormones. Both groups were instructed to eat more than the recommended daily requirement of protein to facilitate muscle gain.
The women exercised three times a week. Researchers compared women on the pill to those not taking oral contraceptives. They found significant differences in lean mass gains, but not in strength or muscle response between the two groups.
When the three week training ended the women who used birth control pills had lower levels of DHEA a steroid hormone produced by the adrenal gland. Women who used birth control pills developed sixty percent less muscle than women not on the pill.
The researchers write “We were surprised at the magnitude of differences in muscle gains between the two groups, with the non-OC [oral contraceptive] women gaining more than 60% greater muscle mass than their OC counterpart.”
Women who use birth control pills had significantly lower levels of anabolic hormones throughout the study period. perhaps explaining why women who use birth control pills develop less muscle. The scientists say more research is needed to explain the reasons behind the results.