(Ivanhoe Newswire) -- Oral contraceptives appear to impair muscle gains
in young women and are associated with lower hormone levels, according to a new
study.
Researchers set out to examine the effect of oral contraceptives (OC) on healthy
women between the ages of 18 and 31. The women participated in a 10-week
whole-body resistance exercise-training program. Their results were compared to
women enrolled in the same program but who were not taking birth control pills.
All of the women were encouraged to consume high levels of protein each day to
make sure they consumed enough calories and protein to promote muscle growth.
They exercised three times a week for 10 weeks under the supervision of exercise
physiologists.
Blood samples were drawn before and after the training and assessed to measure
anabolic (muscle building) and catabolic (muscle breaking) hormone levels in the
blood.
The researchers found there were significant differences in lean mass gain
between the two groups of women, although other muscle responses, such as
strength gains and arm/leg circumferences, were similar. Resting/fasting blood
concentrations of the anabolic hormones were significantly lower in the women
taking OC compared to those not taking the daily pills.
"We were surprised at the magnitude of differences in muscle gains between the
two groups, with the non-OC women gaining more than 60 percent greater muscle
mass than their OC counterpart," the researchers were quoted as saying.
SOURCE: Study presented at the 122nd Annual Meeting of the American
Physiological Society, April 18-22, 2009 in New Orleans
