Should climbers take oral contraceptives?

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Let’s cut to the chase: For many girls and women, working out or playing while on their period sucks.

Menstruation can affect your weight, your mood and your ability to perform. When symptoms arise on game day, they are usually not welcome. For decades, to alleviate these symptoms and even to avoid otherwise unfortunate timing, many female athletes have used hormonal birth control. Contraceptives can ease cramps, regulate and lighten periods, and even clear up the skin.

But the introduction of foreign hormones into the body can be troubling for a host of reasons. For an athlete, the effects of estrogen go far beyond breast development and regulating a monthly cycle. Estrogen can impact overall performance by affecting recovery, injury rate, and power.

Finding information on whether estrogen supplementation is good or bad for athletes, gym climber interviewed Keith Baar, Ph.D., professor of physiology and behavior at UC Davis and renowned tendon health expert. Baar has published 168 articles, totaling nearly 8,000 citations throughout his career. One of his studies, published in early 2019 in Frontiers in physiology, directly addressed the role of hormonal contraception and athletic development.

In Effect of estrogen on musculoskeletal performance and injury risk, Baar and Nkechinyere Chidi-Ogbolu, Ph.D. student at UC Davis, discussed the role estrogen plays in the development of muscles, tendons, and ligaments and, therefore, athletic development and performance. The simple answer: it’s complicated.

estrogen and muscle

Based on animal and human studies on aging, estrogen is definitely beneficial for building muscle mass and strength. For example, in a 2016 study published in the Journal of Endocrinology, ovariectomized rats showed a 10% decrease in strength and an 18% decrease in muscle fiber cross-sectional area (the cross-sectional area of ​​muscle fibers is proportional to the force a muscle can produce) after just 24 weeks. Similar studies (e.g. the one published in the Journal of Applied Physiology) also showed an increase in injured muscle fibers in ovariectomized rats. When ovariectomized rats were given a supplement of estradiol, a form of estrogen, their muscle fiber cross-sectional area and recovery rate returned to normal. In other words, the lack of estrogen led to muscle loss and strength, while restoring estrogen levels (via supplementation similar to oral contraception) returned muscle surface area and strength to those of previous levels.

Postmenopausal women, who have lower estrogen levels after their periods stop, have been shown to lose muscle much faster than their male counterparts. In a 2012 study published in The journals of gerontology, series A: biological sciences and medical sciences, postmenopausal women received estrogen replacement therapy to raise their estrogen levels to those of premenopausal women and the result was a normalized anabolic or muscle-building response. In other words, giving postmenopausal women estrogen helped them build muscle mass at the same rate as their younger, premenopausal counterparts.

In another study published in clinical sciences, 80 postmenopausal women were assigned to one of four groups: exercise, hormone replacement therapy, exercise and hormone replacement therapy, or no treatment, all studied for one year. The group doing both exercise and hormone replacement therapy saw the greatest increase (7.1%) in muscle cross section and a 17.2% increase in vertical leap (the highest point reached from a standing jump). The hormone replacement group saw similar, though smaller, increases in muscle area (6.3%) and vertical leap (6.8%). It should be noted that exercise alone was less effective than hormone replacement therapy alone in maintaining muscle mass.

Birth control pills contain synthetic forms of the natural hormones estrogen and progesterone. Although estrogen can increase the anabolic (muscle building) response, it is also clear that progesterone has a negative impact. A 2011 study published in the Scandinavian Journal of Medicine and Science in Sport, scientists compared formulations of oral contraceptives and found that a contraceptive high in progesterone, on the other hand, inhibits muscle protein synthesis. Athletes who choose to use oral contraception should choose contraceptives that are high in estrogen and low in progesterone.

So, given that estrogen will help athletes build muscle, what are the practical implications? Think of a woman’s natural estrogen cycle as a series of ups and downs. Introduce the pill and the line flattens out – fewer highs and lows only occur during menstruation. This flattening tends to have a negative effect on healthy women trying to build muscle, as it decreases physiologically high estrogen spikes. Therefore, it would follow that healthy women who are trying to build muscle should not take hormonal contraceptives, as it will inhibit their ability to do so.

Estrogen and ligaments

Estrogen, however, also affects tendons and ligaments, complicating the simple conclusion that hormonal contraceptives are bad for athletes. Estrogen has been shown to make ligaments looser. This partly explains why women are two to eight times more likely to tear their ACL than their male counterparts. Loose ligaments mean loose joints, which can put athletes at risk for serious injury.

Rahr-Wagner and colleagues found that women who had never used oral contraception had a 20% higher relative risk of ACL injury than long-term users. According to this research, because estrogen levels in women are highest during the preovulatory and ovulatory phases of their cycle, female athletes who do not use birth control pills are at greater risk during these times than those who do. who use it and may wish to exercise more caution in their training routines during these phases.

So oral contraceptives are bad for building muscle, but good for protecting ligaments by keeping joints tighter.

Estrogen and tendons

While studies indicate that estrogen makes ligaments loose, which is harmful, estrogen has a similar effect on tendons, which can be both good and bad. A stiff tendon will pull the muscle faster, allowing the athlete to achieve better peak power. A stiff tendon is also more likely to pull or tear a muscle.

Due to natural estrogen spikes, women’s tendons are generally looser than men’s and as a result, women suffer from fewer muscle injuries, strains and pulls in the groin and hamstrings. Women also have a lower risk of Achilles tendon rupture, that is, until menopause. Similarly, a 2015 study published in the European Journal of Applied Physiologyshowed that users of birth control pills (i.e. women without high estrogen) were associated with greater muscle damage and pain and a 2006 study, published in International Foot and Ankle, showed an increased risk of Achilles tendinopathy when using oral contraceptives.

It would follow that users of birth control pills might be able to generate higher peak force than their counterparts, but they would also be less able to recover and more at risk of muscle and tendon damage.

The formula

So what should a woman do?

Baar and Chidi-Ogbolu summarized it in this strategy: according to their recommendation, a woman in the off-season training phase had better not use oral contraception, because the high levels of estrogen naturally present in the body generally allow athletes to develop their muscles, recover quickly and be less prone to tendinopathy. However, when a female athlete is in playing season, taking oral contraceptives may be beneficial. Lower levels of estrogen can increase potency as tendons become stiffer. The athlete may not need to recover as quickly as she would normally like, as she will likely have more time between competitions or send-offs. She also may not need to build muscle, just maintain it. Oral contraceptives can also help protect her ligaments from injury during competition.

But to add to the complexity, every woman is different and will react differently to birth control pills. This formula is a good starting point, but it is not a formula for everyone. Climbers will need to experiment, with the guidance of their medical professionals, with their own training formulas and programs to see what works best for them.