Could oral contraceptives negatively impact recovery from resistance exercise?
Overview
What did they test? Researchers investigated if trained females using second-generation oral contraceptives (OC) differed from nonusers (NOC) in recovery from three strenuous resistance exercise sessions completed in less than 24 hours.
What did they find? OC users experienced a significantly greater reduction in isokinetic peak torque at 300°/second (e.g., "explosive strength") for up to 48 hours after the sessions compared with nonusers. Compared to nonusers, OC users also displayed significantly higher blood levels of cortisol, sex-hormone binding globulins, and hs-CRP levels along with significantly lower levels of estradiol, follicle-stimulating hormone, luteinizing hormone, and testosterone. However, assessments of jump height, leg press performance, isometric strength, muscle soreness, knee laxity, Wingate cycle test performance, and repeated run interval test performance revealed no significant differences between groups.
What does it mean for you? Second-generation OC use might impair the recovery of explosive strength after strenuous exercise sessions. This could be related to differences in blood hormone levels and inflammatory mediators affected by second-generation OCs but is unclear from this study. Overall, recovery patterns were not significantly different between OC users and nonusers so it doesn't appear second-generation OC use dramatically affects recovery. If maximum rates of recovery from training are desired, avoiding second-generation OC use or exploring a different form of OC is a reasonable consideration. More research in this area is needed for improved decision-making ability.
What’s the problem?
Oral contraceptives (OCs) are used by millions of women worldwide, including female athletes. Birth control is a common reason for OC use, but OCs are also used for other purposes (e.g., regulating menstrual cycles, managing menstrual cramps, acne). There is limited understanding of how these contraceptives affect skeletal muscle function. In particular, little is known how OCs impact recovery from, and adaptations to, resistance training. Of the small body of research on the topic, some studies suggest that OC use can delay recovery and impair gains in lean mass from resistance training 1 2 3. Other research indicates that OCs can promote increased lean mass in response to resistance training 4 5 and yet other research has reported no significant differences in muscle growth in response to resistance training between OC users and non-users 6.
The differences in these results may be related to the kind of OC being used. There are four recognized "generations" of OCs primarily related to the progestin used in the formulation (i.e., a synthetic form of the progesterone hormone) 7. First generation oral contraceptives contain progestins like norethindrone or ethynodiol diacetate. Second generation forms include progestins like levonorgestrel and norgestrel. Third generation OCs include progestins like desogestrel and norgestimate and fourth generation OCs include progestins like drospirenone. These progestins vary in chemical structure which can affect their functional profiles. For example, second generation forms like levonorgestrel and norgestrel appear to have lower androgenicity than first generation forms. Androgenicity refers to the degree to which a substance (e.g., like OCs) can promote effects that are similar to those of androgens—the primary male sex hormones—or the affinity of a substance to interact with androgen receptors. Some forms of OCs appear to have a higher binding affinity for androgen receptors and this can result in androgenic signaling, or may competitively inhibit androgen receptor activity 3. This is relevant in the discussion on how OCs may affect muscle recovery and adaptation to training since androgen receptor expression and activity can affect muscle protein synthesis and muscle hypertrophy in response to resistance exercise 8. Considering this, in this recent study from Oxfeldt and colleagues 9, the researchers sought to compare markers of recovery and muscle damage in response to repeated resistance exercise sessions between second generation OC users and non-OC users.
Purpose
The purpose of this study was to compare markers of muscle recovery and damage after repeated bouts of resistance exercise in trained females using second-generation OCs versus non-OC users.
Hypothesis
The researchers predicted that OC users may show impaired recovery and a more pronounced increase in markers of muscle damage following resistance exercise.
