When I heard Swiggy chide his male friend by saying, “Pull your tampon out and run!” I had to ask him to repeat what he’d said. In thinking of my own personal races in which I had needed a tampon, I assured Swiggy that was NOT a good idea. “It means that the guy needs to stop whining or complaining and suck it up! It’s calling him a slow woman on her period,” he said. This therefore pathetically suggests that the discomfort and sluggishness women complain about are only cowardly excuses in their heads and factors that they can and should disregard as irrelevant to their performance. I began wondering, should and can a woman’s menstrual cycle and its unique phases be taken into consideration when planning races and hard workouts? The answer is clearly “yes.”
While an uncomfortable and typically taboo topic for most men and some women, it’s something that every woman runner needs to take into consideration when planning a training schedule and understanding running performance. And in order to grasp the important differences occurring during the phases, one has to first understand the menstruation cycle. The first day of the cycle is the first day of menses. Bleeding is usually complete by day 5 or 7. Days 1-14 are called the follicular phase. By day 14 or 15, ovulation begins with a surge in estrogen and lutenizing hormone. The following phase lasts until the last day (28 on average) and is called the luteal phase. During this phase estrogen is at its highest triggering several interesting changes, many of which hinder performance.
Many running articles focus on endurance female athletes with a heavy training load experiencing ammenoheric or irregular cycle issues. The research findings on the effects of a regular menstrual cycle, on average testing women ages 20-35, vary widely thanks in part to the rollercoaster of hormones. University of Sidney researcher Dr. Xanne Janse De Jonge suggests that the pulsating nature of hormone secretion, the timing of testing and the individual variability in estrogen and progesterone levels make testing a challenge. However, most studies agree on several key aspects.
Ask the Coaches: Foamy Sweat
During the luteal phase, an increase in estrogen promotes fat utilization because the female body is trying to spare glycogen. What does this mean for the female 10K or marathon runner? According to Dr. Stacy Sims, Exercise Physiologist-Nutrition Scientist at Stanford University and director of Carmichael Training Systems’ R&D Department, the female runner needs to be extra careful to be sure she is taking in at least 40 grams of carbohydrate/hour if racing or intensively training during the luteal phase. As for the follicular phase (the first two weeks of the cycle), the body is readily using, not sparing, its glycogen and blood glucose so while the female runner should still be taking in 40 grams of carbohydrates/hour, she has more of a buffer if she forgets. “Know your baseline and increase it 10-20 grams/hour if racing during your luteal phase,” says Dr. Jason Glowney, a physician at the Boulder Center for Sports Medicine. As in most nutritional cases, he suggests making sure to try it in training first.
Low blood sugar during the luteal phase may result in decreased lactate thresholds [Janse de Jonge, Xanne A.K., “Effects of the menstrual cycle on exercise performance.” Sports Medicine, 2003; 22 (11): 833-851]. While lactate threshold variations depend more upon training status than anything, there is lower blood lactate accumulation in the luteal phase than the follicular. Thus LT occurs at a higher intensity in the luteal phase than the follicular [Sims ST, Rehrer NJ, Bell ML, Cotter JD. “Pre-exercise sodium loading aids fluid balance and endurance for women exercising in the heat.” We may earn commission from links on this page, but we only recommend products we back, 103: 534–541, 2007].
Plasma Volume: The Big Player
The second most important factor to consider is the change in thermoregulation during the luteal phase. While women may complain of bloating during the days leading up to their periods, fluid, says Sims, is actually being redistributed not retained. The drop in plasma volume is an illustration of this.
Plasma is primarily what allows us to sweat. When a woman’s plasma volumes decreases (on average) 8 percent [Stachenfeld NS, Keefe DL, and Palter SF. “Estrogen and progesterone effects on transcapillary fluid dynamics.” American Journal of Physiology, Regulatory Integrative & Comparative Physiology, 281: R1319-1329, 2001], they are slower to begin to sweat and therefore their body temperature rises on average 0.3-0.5 percent Celsius. [Kolka MA and Stephenson LA. “Effect of luteal phase elevation in core temperature on forearm blood flow during exercise.” We may earn commission from links on this page, but we only recommend products we back, 82: 1079-1083, 1997.] With lower plasma comes a thicker blood concentration which results in slower blood flow between muscles. Consequently, there is a slower recovery time due to the build-up of lactic acid in muscles and compromise of oxygen delivery. [Sims ST, Rehrer NJ, Bell ML, Cotter JD. “Pre-exercise sodium loading aids fluid balance and endurance for women exercising in the heat.” We may earn commission from links on this page, but we only recommend products we back, 103: 534–541, 2007.] Cardiovascular strain may also result from training/racing in hot and humid conditions with an elevated body temperature.
A female athlete in her luteal phase should try to address these patterns by pre-loading a little more than usual with a sodium-based drink. Sims’ doctoral research found that a sodium load of 164mmol Na+/L dosed in 10ml/kg expands plasma volume on average 20 percent. Be more cognizant of heat stress and make sure you are making appropriate adjustments in hydration. Glowney suggests a woman perform a sweat-loss weight test during different points in her cycle to see if there is an individual difference in her sweat loss during menstruation, the follicular phase and the luteal phase. A runner doesn’t want to over hydrate and carry around extra weight when, on average, one runs 2-2.5 seconds faster per pound lost if fitness is being maintained. Hemoglobin and Hematocrit: Are they players?
A woman’s performance suffers due to a drop in iron levels as a result of blood loss during her period, right? Apparently wrong. Several studies have shown that, contrary to this widespread belief, the average drop in a woman’s hemoglobin and hematocrit (iron) levels is not significant enough to affect performance. [Janse de Jonge, Xanne A.K., “Effects of the menstrual cycle on exercise performance.” Sports Medicine, 2003; 22 (11): 833-851] However, Glowney warns, “If you have high blood loss during your menstrual cycle, you might need to supplement and keep a close eye on your iron levels. The most important factor to check is your ferritin level. It will drop even before you actually become anemic.”
Anemia is multifactorial; having a period doesn’t necessarily make you anemic, he asserts. Being iron-deficient isn’t equivalent to being anemic. “Females are likely to be more prone to iron deficiency because of the iron loss that occurs with the accrued blood loss from menstruation,” Glowney explains. “Some also theorize there might be male to female differences in iron content ingested in diet too.”
Studies have shown that running can potentially cause any runner (regardless of gender) to lose iron through their gastrointestinal tract and even through their sweat, says Glowney, an endurance coach and former elite-level triathlete. Then there is the footstrike theory which suggests that runners lose iron when the red blood cells in their feet are broken during the pounding occurring when they run. A relatively new theory, Glowney reports, surmises that the peptide hepcidin, which decreases iron uptake, is secreted by the liver when the body recognizes itself in a state of acute inflammation. Eight to 10 hours after a hard race/training session the body will release hepcidin. So iron absorption for all runners is compromised after working at a high intensity.
According to Glowney, the focus of menstrual cycle research focuses on the idea that performance is compromised during the luteal phase predominantly due to critical changes in thermoregulation and metabolism. Yet, he cautions, “It’s really hard to make concrete assertions with regards to performance during menstruation.”
Foods That Cut Inflammation to Improve Performance!
According to Sims, the high levels of progesterone (naturally thermogenic) during the luteal phase not only contribute to the thermoregulation issue, they also stimulate the phrenic nerve. This nerve triggers diaghram contraction and can result in an increased respiratory rate and potentially hyperventilation. In this case, the runner is blowing off too much carbon dioxide and thus disrupting the normal balance of carbon dioxide and oxygen in the blood.
Sims, an endurance athlete and former coach, says the second day of bleeding is actually when the levels of the disruptive but necessary hormones, estrogen and progesterone, hit rock bottom. In addition, a woman’s weight is highest during the late luteal phase and first day of menses and then drops dramatically, according to Jonge’s research. So, in theory, bloating and cramping and rotten psychological outlooks aside, some researchers say racing is ideal mid-way through one’s period. But who are we kidding, the other three factors can have disastrous effects on a race. Wouldn’t anyone, male or female, find it tough to run their best race with a stabbing headache, low back pain, and/or the feeling of your guts being wrung out? As for taking NSAIDS like ibuprofen to ease cramping before a race, don’t do it! These drugs make one more susceptible to kidney failure and hyponatremia. Sims recommends taking white willow bark or naproxen sodium (i.e. Aleve) to help with PMS and cramping.
Dear Diary: Pay Attention!
Glowney gives his best advice to menstruating females, their coaches and parents: “All female athletes should keep a training cycle diary.” In this way a female can track whether or not there appears to be a pattern in her cycle that leads her to believe racing during a particular phase could be a detriment to her performance. Plan your races during a time when you realize you are typically “on.” He also suggests females get their ferritin tested frequently. “Know what it is when you are feeling good and then get it tested when you are feeling low.”
“Watch high-intensity efforts and recovery during the luteal phase,” Sims recommends. “It’s a bit harder on the body due to the physiological shifts in fluid, temperature and fuel, so women are more predisoposed to overtraining and under-recovery during these two weeks.”
Many of us remember Uta Pippig’s 1996 win at the Boston Marathon where finish line photos showed her wild-eyed and grinning despite evidence of menstrual bleeding and diarrhea on her legs. I seriously doubt anyone encouraged Pippig by saying, “Pull the tampon out and run.” Clearly the power of her positive and determined mind played a crucial role in her win despite the indignity of her appearance. How much can one’s mental outlook on a race affect the proven physiological effects of a menstrual cycle? Just as runners time their nutrition around their races, will more women plan their races around their cycles? What will further research reveal as more women move in the direction of birth control that eliminates the period all together? Clearly the doors are wide open for further research on the menstrual cycle, which is always variable and a variable for women runners.
Amanda McCracken is a D3 Multisport triathlon and running coach and has been running and cycling competitively since she was 13.
