Trail and ultrarunners are not immune to the countless changes that occur with the aging process. The following discussion highlights the hormonal changes that occur as female athletes age. More specifically, we’ll cover how hormonal changes through perimenopause and menopause impact widespread physiological changes and ultrarunning performance for women.
Roles of key female hormones
First, it’s helpful to understand the roles and cycles of key female hormones. Let’s begin with estrogen. it is difficult to overstate its importance as both a reproductive hormone and an anabolic hormone. Estrogen contributes to the regulation of metabolism and cholesterol levels, maintains bone density, optimizes brain function, promotes inflammation, regulates thermoregulation, contributes to skin and muscle mass maintenance, and helps maintain the appropriate amount of collagen in connective tissue.
Progesterone’s main role in female athletes is reproduction, and it is also an endogenous anabolic hormone. Like estrogen, progesterone contributes to tissue maintenance, including muscles and connective material. The normal variability of progesterone during the reproductive years supports optimal neurological function. Progesterone and estrogen work in a complimentary manner to protect bone health by upregulating the bone remodeling process. And progesterone acts to counter the inflammatory effects of estrogen by decreasing systemic inflammation. These two hormones regulate metabolism by promoting balanced levels of blood glucose and are some of the main drivers behind muscle mass maintenance and repair.
Fluctuations in reproductive hormones
Following puberty and during reproductive years, most females have predictable oscillations in their reproductive hormones, especially estrogen and progesterone. During a typical menstrual cycle, which can vary between 23-35 days and still be considered ‘normal’, both estrogen and progesterone are relatively low during the first approximately seven days of the cycle. From about days 7 through 10, estrogen, follicular stimulating hormone, and luteinizing hormone increase significantly. This is when ovulation occurs, and an egg is released. After ovulation, all sex hormones decrease to a low level, they remain low until several days prior to the beginning of the menstrual cycle. At this time, progesterone climbs to its highest level of the cycle and estrogen levels increase moderately. These two hormone levels then decline, assuming an egg is not fertilized, and the cycle begins again.
Hormone fluctuation for aging female athletes
As women age and move toward the onset of menopause (technically 12 months with no period, occurs at an average age of 51 years old) the hormonal variations that were typical during reproductive years begin to vary. This stage, known as perimenopause, begins between the ages of 40-44 for most women.
Note that the timing for the onset of peri and post menopause is primarily linked to genetics. The age at which a female ultrarunner’s mother experienced these turning points is a strong predictor for when hormone fluctuations and the cessation of the menstrual cycle will occur. Additionally, the symptomology described in the following discussion varies widely between individual runners. Those with elevated levels of fitness at the onset of peri and post menopause tend to experience less severe disruptions to their physiology and running performance.
During perimenopause it’s common for estrogen to elevate more significantly, and remain elevated longer, compared to the generative years. In contrast, progesterone levels tend to remain lower compared to the reproductive years. This pattern is especially pronounced during non-ovulatory cycles when an egg is not released during the menstrual cycle. This occurs more frequently as females approach menopause. Some women may experience declines in both estrogen and progesterone throughout perimenopause. This pattern is more typical of female ultrarunners with a pattern of light periods or amenorrhea.
Effect of perimenopause on performance
How do these fluctuations affect athletic performance, especially as it pertains to trail and ultrarunners? Just as hormone variations are highly individual, so too are the outcomes of these changes. However, because estrogen levels tend to be more elevated and progesterone levels tend to drop during perimenopause, female ultrarunners during this stage of life often experience slower rates of recovery.
Increased need for recovery
Remember that these two hormones act together to repair tissues, including protein synthesis. Higher estrogen and lower progesterone will disrupt the cellular restoration processes, in part due to increased systemic inflammation. Many female ultrarunners experience the need for more recovery in their programs because the rebuilding process takes longer with increased age.
Increased likelihood of injuries
Additionally, progesterone acts to increase ligamental tension and it helps modulate pain tolerance. Drops in progesterone levels during perimenopause can lead to an increased likelihood of acute injuries such as sprained ankles and the perception that levels of pain associated with fatigue late in ultramarathons or high intensity interval training have increased compared to past experience.
These two hormones also affect appetite and metabolism. Estrogen tends to increase appetite while progesterone promotes satiety. Therefore, if estrogen levels are elevated while progesterone levels are lower than normal, a female ultrarunner is likely to feel hungrier and at the same time, not receive the usual signals that they feel full. This is one reason that women at this age may find it more difficult to maintain a familiar body composition from before the onset of perimenopause.
Hormone fluctuation with menopause
Several other key-to-performance hormones decrease as women enter perimenopause. Female ultrarunners can expect a drop in levels of growth hormone, testosterone, and melatonin. A decline in melatonin tends to increase the need for recovery time because melatonin is one of the main regulating hormones for sleep. So, not only are tissue repair processes already slowed, but sleep interruptions can further exacerbate the slowing of repair activities.
While females have much lower levels of naturally occurring testosterone compared to males, testosterone helps maintain muscle mass and contributes to red blood cell (RBC) production. With a decline in both muscle mass and RBC’s, a female’s oxygen carrying capacity and delivery mechanisms will diminish somewhat. This is one of the main reasons that VO2 capacity declines with increased age.
Decreased oxygen carrying capacity tends to result in slower speeds for high intensity efforts, or at least a plateau in performance at lactate threshold (e.g. Tempo intervals in running) and VO2 max (e.g. Running Intervals)
Muscle building and repair
Lastly, growth hormone is a main driver behind cellular rebuilding processes and normal metabolism, therefore a decline in growth hormone also tends to increase the recovery time needed between hard training sessions. This can make attaining or maintaining a preferred body composition more challenging for women that participate in ultrarunning.
With the onset of menopause, estrogen and progesterone still circulate. However, the level for both key hormones are much lower than they were during the reproductive and perimenopause years. Without the anabolic effects of these two hormones, muscle repair and metabolism tend to slow. The flatlining of anabolic hormones usually necessitates more recovery time for women in their menopause years compared to both the perimenopausal timeframe and the reproductive years. Bone density decreases for all female runners following the cessation of the menstrual cycle and bone loss is ongoing throughout menopause. Female athletes, therefore, should increase focus on nutrition and strength training before perimenopause or as soon as possible once perimenopause symptoms emerge. Early interventions may lessen natural declines in muscle mass, strength, and neuromuscular coordination. These shifts in nutrition and training are key to limiting performance declines and maintaining overall health.
Stress hormones and secondary reproductive hormone levels also increase as female ultrarunners approach perimenopause. These hormones include norepinephrine, epinephrine, and parathyroid hormone. Levels of secondary reproductive hormones, including luteinizing hormone and follicular stimulating hormone, increase in an attempt to maintain fertility.
Most of the processes that involve stress hormones are rather complex, but chronically elevated levels of stress hormones tend to negatively affect athletic performance. Elevated levels of stress hormones also increase the need for recovery, especially between challenging bouts of training.
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More specifically, stress hormones contribute to vascular function, contribute to the regulation of sleep and wake cycles, and increase mental alertness. They also help maintain bone health and neuromuscular activity, and regulate metabolism. Women ultrarunners may experience less agility, especially on technical terrain, because of inhibited neuromuscular function as well as a decline in ligament tension.
Elevated stress hormone levels can further exacerbate sleep disturbances, beyond the effects of lowered levels of melatonin and elevated estrogen. Metabolism, already affected by fluctuations in estrogen, progesterone, and growth hormone, also tends to slow more in conjunction with elevated levels of epinephrine.
Additional changes that affect performance
Elevated stress hormones can also lead to moods swings, which can affect motivation for training and other life activities. This can be jarring for ultrarunners who have usually enjoyed superior levels of drive. A decline in excitement for training and racing can be confusing and deflating. Worse, this can lead to reduced activity, which In turn reinforces the loss of drive, creating a cycle that can be very challenging to emerge from.
Lastly, loss of bone density is all but guaranteed when elevated levels of the stress hormone parasympathetic hormone signal the release of bone calcium into the bloodstream. These elevated levels of blood calcium may be associated with a heightened risk of cramping both within and outside of training and competitions, even for females who previously had little or no problems with cramping prior to peri or post menopause.
Much of this may not be welcome news for women in the sport of ultrarunning. However, it should be helpful to know that healthier athletes, those with higher levels of fitness, tend to be less impacted by these hormonal and physiological transformations. In a follow-up article, we’ll discuss specific interventions that may potentially mitigate performance declines for female ultrarunners. Life is about change, but women can enact successful strategies to lessen the impacts of aging on performance. Stay tuned to learn what tactics can be deployed to allay deteriorations in ultrarunning performance.
By Darcie Murphy,
CTS Ultrarunning Senior Coach
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