Oral contraceptives set back muscle gains in young women

April 17th, 2009 - 4:10 pm ICT by IANS  

Washington, April 17 (IANS) Active young women who use oral contraceptives (OC) may be setting back their muscle gains, according to a study.
“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 said.

Seventy-three 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 one comprised of 34 women who used OC. Group 2 consisted of 39 women who did not take birth control pills (non-OC).

The women were encouraged to consume at least half a gram of protein per pound of body weight per day to make sure they consumed enough calories and protein to promote muscle growth.

They exercised three times per week for 10 weeks under supervision.

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.

Researchers found that there were significant differences in lean mass gains. However, 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 versus non-OC users throughout the study. At the same time, plasma concentrations of cortisol (catabolic hormone) were elevated.

The OC users had reduced DHEA hormones at the end of the training period. By contrast, the non-OC user’s levels did not change.

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