Researchers have been examining the effect of oral contraceptives (OC) on female muscle mass and found that use of The Pill impairs muscle gains in young women, and is also associated with lower hormone levels. The findings were presented at the 122nd Annual Meeting of the American Physiological Society in New Orleans.
The study involved 73 women between the ages of 18-31 who were assigned to two groups based on whether they were using The Pill or not. They then completed a 10-week whole-body resistance exercise training course. The participants exercised three times per week for ten weeks under the supervision of exercise physiologists. They performed a variety of exercises to including chest press, lat pull down, leg extension, triceps extension, arm curl and abdominal crunch. Blood samples were taken before and after the training and assessed to measure anabolic (muscle building) and catabolic (muscle breaking) hormone levels in blood.
Key findings included:
- There were significant differences in lean mass gains (OC: 2.1 versus non-OC: 3.5). Other muscle responses such as strength gains and arm/leg circumferences were similar between the OC and non-OC users.
- Resting/fasting blood concentrations of the anabolic hormones were significantly lower in women taking OC vs. non-OC users throughout the study period.
- Those OC users had reduced DHEA hormone at the end of the training period. By contrast, the other participants' levels did not change.
"We were surprised at the magnitude of differences in muscle gains between the two groups, with the non-OC women gaining more than 60% greater muscle mass than their OC counterpart," noted the researchers. They added that even though the study has observed negative effects of oral contraceptive use on muscle gain in the context of resistance exercise training, "future studies are needed to help explain the reasons behind the results."
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Source: American Physiological Society