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Female Cycle and Its Effects on Alpine Performance
By C. W. Schurman, CSCS
Female climbers have a lot to keep in mind as they train, including but not limited to proper timing of their Back-to-back outings in order to peak properly; adequate nutrition for sufficient recovery and fueling; and appropriate strength training overload to make sure they have enough strength for heavy packs. Add to that the complications of sometimes unpredictable hormonal or menstrual cycles and you have a recipe for confusion. This article shares information on the female cycle that may help with long term expedition and outing planning.
Pre-Menstrual Syndrome (PMS)
It comes as no surprise that alpine climbing expeditions are scheduled with respect to seasonality, weather, trade winds and the like. They typically and historically have been male-dominated, though that has started to change in recent years. It also probably comes as no surprise that little to no weight is given to a woman’s menstrual cycle. However, the female climber who suffers from unusually severe pre-menstrual symptoms, lower back pain, low energy levels or cramping at some point in her cycle may need to take this into consideration when planning her climbing adventures. Whenever possible, more intense climbs should coincide with the strongest parts of a woman’s cycle.
Nearly all women are familiar with symptoms of bloating, headaches, fatigue, and cramping during the late luteal phase, or the latter half of the cycle encapsulating days 15-28, including post-ovulation and pre-menstruation. Symptoms might include depression, malaise, moodiness and irritability as well as painful menstruation, all of which can negatively impact strength, speed, endurance, and motor skills. Studies suggest that exercise helps diminish some symptoms, while cutting back on exercise exacerbates them.
Hormonal Changes and Performance
It is the pre-menstrual fall in estrogen and progesterone that causes PMS symptoms. However, while both decline leading up to the 14th day in a typical cycle, progesterone peaks on about the 20th day, triggering PMS. Researchers have tried to address whether there is a natural portion of the female cycle during which women athletically perform their best. In one study, eight fit, normally menstruating females were asked to run at intensities of 70% and 88% of Max Heart Rate (MHR). The phase of the cycle one week after ovulation and one week prior to menstruation turned out to be the most difficult for exercise, when psychological health plummeted.
However, the lactate threshold WAS NOT influenced by the menstrual cycle phase. In further research at Springfield College, Massachusetts, eight female distance runners were asked to run at high speeds for short periods of time and as far as possible at an intensity of 90% of MHR. The variables measured included VO2 max, blood lactate, lactate threshold (LT), maximal heart rate (MHR) and fat oxidation, and remained the same regardless of menstrual cycle stage (MSSE, 1993 Horwill).
Other studies relate an increase in perceived exertion during premenstrual and early menstruation days. Some suggest that women experience slightly elevated heart rates for the same exertion during the post-ovulatory phase. Still others report that effects of PMS seem to alter performance as the exercise tasks increase in difficulty and complexity; such effects could prove dangerous or even disastrous at extreme altitudes where neural function and brain capacity are already reduced due to lack of available oxygen.
For most women, however, menstruation will likely be more of a nuisance rather than something that interferes with strength, speed, coordination, endurance, or performance. In one study, 13-29% of women actually reported improved performance during menstruation. The female menstrual cycle varies so widely in duration, intensity, and symptoms that it is up to each individual as to what she feels comfortable doing.
Increase in Body Temperature
Various surveys of world-class athletes show that the vast majority of women feel that menstruation itself has absolutely no effect on their athletic performance. However, during the last half of their menstrual cycle, when women have a higher body temperature, the extra heat could interfere mildly with performance. With increased core temperature, the heart has to pump extra blood from your heated muscles to your skin in order to help dissipate heat, resulting in increased sweating, and this extra effort reduces the quantity of blood available to be pumped directly to your exercising muscles. During an expedition or intense training, therefore, factor your cycle into planning, in order to be certain that you replenish not only the fluids lost through increased sweating, but also important electrolytes to help avoid hyponatremia.
Potential Effects on Climbing
Several studies demonstrate reduced reaction time, neuromuscular coordination and manual dexterity during pre-menstruation and menstrual phases. Considering there is evidence that blood sugar levels, breathing rates and thermoregulation vary during the menstrual cycle, the slight decreases in aerobic capacity and strength reported by some women may indicate a physiological basis for some observations.
Some women may feel that they can perform at a slightly higher level when they are not menstruating, but generally they will not need to manipulate their cycles to enhance alpine performance. In extreme cases—i.e. severe pain that might coincide with an important attempt at a summit—a female climber may decide it’s in her best interest, in terms of comfort, to manipulate her menses cycle by taking birth control pills for several months prior to the climb and then stop taking them, ten days before her climb begins. She will usually start menstruating within 3 days and stop menstruating right before she starts her climb. While this may work for climbs shorter than a month, timing can be trickier for an alpine expedition lasting longer than 4 weeks.
Detailed Cycle Log
To figure out when you are naturally strongest and have the most energy during your cycle, chart three pieces of information: 1) emotional states or moods; 2) basal temperature (first thing in the morning) and 3) resting heart rate (RHR) upon waking. Include your activities, exercise, and athletic performance to establish strongest and best training days and when you feel sluggish, slow or impaired. This will facilitate modifying your training schedule by planning for strenuous climbs, easier and harder strength workouts, peak training, and adequate recovery.
Workout factors that you can adjust according to your cycle are the number and duration of workouts per week, repetitions per set, intensity, and difficulty of movements in terms of skill level and injury risk. You can also include nutrition considerations to optimize recovery and fuel stores. Since testosterone peaks right around the time of ovulation, it may be beneficial to plan for peak strength training loads or toughest single-day climb efforts right around the time of ovulation, detectable via basal temperature measurements as a natural upward shift by about .5 degrees F.
Cross training may help you salvage a workout session, both mentally and physically. For example, since running involves repeated impact, which could add distress to a lower abdominal region already disturbed by water retention and cramping, or lower back region prone to discomfort from relaxed SI joint due to increases in the relaxin in your body, consider substituting a non-weight bearing activity like stationary cycling or swimming, or try including a session of yoga in order to bring some temporary relief.
Increased Risk of Injury?
Some studies indicate that women experience an increase in musculoskeletal and joint injuries during the premenstrual phase. This may be due to higher relaxin levels, resulting in increased flexibility and elasticity of connective tissue. Greater levels of relaxin may weaken the ability of lumbar spine supports to withstand shearing forces, particularly in high impact activities. Several studies associate high levels of relaxin with lower back pain in women during pregnancy, and similarly high levels in non-pregnant women with posterior pelvic pain. Try modifying your weight training during various phases of your cycle by reducing the intensity (weight used) and volume (number of sets and exercises completed) during the days before and a few days into menstruation. This will allow you to compensate for increased fatigue while also preserving joint integrity.
A woman’s hormonal cycle is not to be taken lightly. By accurately tracking your moods, performance, intensity and strength levels, you can get a much better sense of how you do in different phases of your cycle. This will help you to plan accordingly so that you can perform optimally in the mountains. With proper tracking, if you happen to have an off day or two, you can readily attribute it to your hormonal cycle and recognize that in another few days you should be right back on track, rather than incorrectly interpreting it as a sign of overtraining and losing valuable conditioning time.