Overview of Hormones and the Menstrual Cycle
Training for an athletic competition or exercising is already hard enough but along with the unique fluctuation in a woman's hormones this can make it near enough impossible. Yes, that’s right we’re talking about the time of the month! We hope by the end of this blog you will be in better place with understanding your hormones and cycle which we hope will enhance your athletic performance.
The menstrual cycle starts on day one with menses or more commonly known as the “period,” which lasts between three to seven days.
The full first half of the menstrual cycle is called the follicular phase which averages 13 days. This phase includes menses and ends with ovulation. Ovulation is the middle phase of the menstrual cycle and ends when the egg is released from the ovary. After ovulation ends, the luteal phase begins, which typically lasts 13 days as well and ends when menses begins again.
Oral contraceptives are very common among female athletes, with about half of the women competing at the Rio Olympic Games using some form of oral birth control.
While this is useful in preventing the cyclic nature of hormones during the menstrual cycle, it appears the or contraception does in fact interfere with normal immune homeostasis.
Data taken from the 2012 London Olympic Games showed women were 60% more likely to get sick, which affected training or competition. This increase in illness is likely a result of oral contraception use with studies showing elevated C-reactive protein levels among women using oral contraception than the women who were naturally cycling.
Now lets look closer at the different phases and see how the change in hormones during each phase can be used advantageously for performance.
Follicular Phase
Approximately 75% of women athletes have negative side effects in relation to their menses. However, this phase is not all bad for athletic performance, as a spike in Estrogen after menses it typically brings a boost of energy. During this part of the cycle, the female body is primed for high-intensity workouts and it is the best time for strength training. This is because of the effect Estrogen has on the muscle. The rise in Estrogen also increases the body’s ability to recover in between workouts (which we all need after a big workout.) During this state of increased Estrogen, it is also important to not overdo your activities.
Estrogen increases type III collagen mRNA. This is in part responsible for decreased tendon stiffness during maximal muscle loading in women and decreases stiffness of the sinew, which causes an increase in elasticity of the knee. Studies have shown that there is an increased risk of anterior cruciate ligament (ACL) injuries during the late follicular phase. The flip side of this is that women have much lower incidence of muscle strains and Achilles ruptures due to this decreased sinew stiffness.
During this period women utilize stored carbs (glucose) much better, which allows for better endurance. Once Estrogen levels spike, the body can’t utilize the glucose stores as efficiently due to the suppression of gluconeogenesis in the liver by Estrogen and progesterone. At this time of your cycle, carb loading is very important as these external carbs are the main source of fuel for female athletes. The follicular phase ends upon ovulation.
Ovulation
Ovulation begins when luteinizing hormone (LH) levels spike, the egg is released, and Estrogen levels drop rapidly. However, during the three-to-five-day window prior to the ovulation portion of the cycle, Estrogen levels remain very high, as well as a spike in luteinizing hormones. Which is an ideal time for strength training. But the body switches to fat as a fuel rather than glucose, which results in less available energy for high-intensity activities and carb loading is more important. As the luteal phase begins, Estrogen declines and progesterone begins to rise.
Luteal Phase
The luteal phase is highlighted by a large increase in progesterone and a rebound of Estrogen levels. With both Estrogen and progesterone levels high, the body is not primed for high-intensity workouts. Endurance can also be affected at the end of this phase as there can be a drop in blood plasma volume, decreasing oxygen levels to the muscles. Estrogen results in fluid retention and as Estrogen levels begin to drop before menstruation, the fluid is redistributed causing this decrease in volume. It is very important to up protein intake during this time as the body increases protein catabolism due to the increased progesterone levels. There could also be a slight disadvantage due to higher basal body temperatures, although this would only occur under extreme heat conditions.
When people think of muscle, they usually think of testosterone.
However, Estrogen plays a very important part in muscle structure and function and is usually overlooked. In fact, there is no difference in relation to sex when looking at force in relation to muscle cross-sectional areas (CSAs).
Estrogen is an important factor in this because it is important for maintaining proper muscle conformations. Meaning the muscle fibres are aligned properly and the myosin heads are primed to bind with the strong binding site of the actin filament rather than the weak binding site. Estrogen is responsible for more strong-binding reactions of myosin heads to actin, resulting in more force generation. This is also suggestive of why women respond better to strength workouts during the late follicular phase when Estrogen is highest.
Now you may be asking yourself, Estrogen is high in both late-follicular as well as mid-luteal phases, why does this increase in muscle strength and growth only occur in the late-follicular phase? This is a great question and progesterone itself is important for protein synthesis. But animal data has shown that when Estrogen and progesterone are present together, like in the mid-luteal phase, they may counteract each other. Therefore, resistance training is best during the late-follicular phase only.
For oral contraception users, a triphasic oral contraception with low progestogen in the first two weeks also showed this same increase in resistance training response. It has also been shown that women using oral contraception that contain constant amounts of ethinyl Estradiol (EE) and progestins showed lower protein synthesis. This suggest that progestins have an anti-androgen effect on protein synthesis when paired with Estrogen.
How can you test your hormones?
How can you use all this information to enhance your training and performance? For women who are naturally cycling, it is important to understand the exact timeline of your cycle so you know when you are in each phase and can get the most out it. Hormone Lab offers a menstrual cycle mapping kit that allows for accurate mapping of the menstrual cycle through testing of LH, and metabolites of progesterone and Estradiol in urine. For women on hormonal birth control, it may be important to understand where your hormone levels are at while on the contraceptives. This is best done using our LCMS saliva profile. This profile tests for 18 hormones, melatonin, three steroid synthesis inhibitors, and most importantly, the synthetic Estrogen EE. It is important to understand your EE levels to fully understand your full Estrogen load on top of your Estradiol (E2) levels. EE binds stronger to the Estrogen receptor than Estradiol and is therefore much more potent. The full Estrogen load is a calculation of EE and E2 values to understand the Estrogen receptor binding capacity.
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