How Hormones Impact Running Performance
Are Your Hormones Jacking Up Your Running Performance?
(Ladies, this one's for you… and the answer is yes!)
Let’s start this blog entry with a little story and see if it hits home for any of you.
Mary, a 38-year-old runner is training for her fifth half marathon. She is in great shape and takes good care of herself. Beyond committing to her running plan, she does strength workouts twice a week, eats a balanced diet based on whole foods, hydrates like a champ, ensures she gets adequate sleep, foam rolls and stretches daily. Mary does speed work every Wednesday, long runs every Saturday, and takes one day off of exercise each week to let her body recover. Mary’s half marathon personal best is one hour and fifty minutes.
Last week Mary completed her 9 mile build-up run at an average pace of 8:45 per mile and felt great… like she could have kept going for another couple of miles had her training plan called for it. It is the perfect summer day and Mary is scheduled to run 10 miles. She starts out and feels a little bit sluggish, but tells herself to just “settle in” and it will get better once she hits her stride. A mile or two goes by and that sluggish feeling persists. Her legs feel quite heavy, her heart feels like it is beating much too fast, and she is having a lot of trouble maintaining pace. Mary is dumbfounded when, at mile 5, she has to stop to catch her breath. As soon as her heart rate recovers, she sets out again, only to stop again at miles 6, 7 and finally 8 when she ends her run short of her goal. She is disappointed, questioning her abilities, and overthinking everything she did in the days leading up to this run that would have caused her to perform so poorly.
What Mary doesn’t know, is that by being in the luteal phase of her menstrual cycle, her hormones may very well be to blame for her lackluster training run.
As a female runner, I wish someone would have explained all of this to me long ago. It would have saved me years of beating myself up after runs - and races - that didn’t go as planned. So I hope this blog will save many of you from doing the same…
First, a little refresher on the phases of our cycles and the hormones that are prominent in each.
Follicular Phase (Days 1-13, on average)
The follicular phase begins on day one with the onset of menstrual flow. Menstrual flow occurs when estrogen and progesterone levels drop, which causes the lining of the uterus to shed. After menstrual flow stops, estrogen levels begin to slowly rise, while progesterone levels remain low.
Ovulatory Phase (Day 14, on average)
Rising estrogen causes a rise in luteinizing hormone and a mature egg is released from the ovary.
Luteal Phase (Days 15-28, on average)
Progesterone levels rise after ovulation and remain high throughout most of this phase. Estrogen levels initially drop after ovulation, but then start to slowly rise again. If the egg is not fertilized, estrogen and progesterone levels drop, menstrual flow starts and the luteal phase ends. It is during the luteal phase that female runners may experience an impact to their performance.
How Hormones Impact Running Performance
Drop in Plasma Volume
High Heart Rate
Progesterone, the hormone that dominates the luteal phase, decreases plasma volume by eight percent, on average. Plasma is what allows us to sweat, thereby regulating our body temperature. During the luteal phase, women experience an increase in their basal body temperature by an average of 0.4 degrees Fahrenheit. Research studies have shown that in the middle of the luteal phase, increased body temperature can hurt running performance, especially during prolonged exercise in hot, humid climates.
Additionally, with lower plasma comes a thicker blood concentration resulting in slower blood flow between muscles. This leads to slower recovery time due to build-up of lactic acid and compromised oxygen delivery.
Finally, cardiovascular strain may also result from training/racing with an elevated body temperature. High levels of progesterone during the luteal phase stimulate the phrenic nerve, which triggers diaphragm contraction and can result in an increased respiratory rate and hyperventilation.
Decreased Glycogen Utilization
Low Blood Sugar
Decreased Lactate Threshold
Estrogen plays a role in metabolism by increasing fat utilization and decreasing utilization of stored carbohydrates, while progesterone increases the breakdown of proteins. During the luteal phase, and particularly the mid-luteal phase, when estrogen levels are high, the body is not as capable of utilizing stored carbohydrates (glycogen), leading to low blood sugar.
Low blood sugar during the luteal phase may result in decreased lactate thresholds. While lactate threshold variations depend more upon training status than anything, there is lower blood lactate accumulation in the luteal phase resulting in lactate thresholds occurring at a higher intensity.
Don’t give up running for two weeks out of each month just yet. There are simple ways to counteract the effects of menacing hormones during the luteal phase.
Studies have shown that various forms of pre-cooling, especially cold-water immersion and crushed-ice ingestion, before an event can improve endurance, specifically running performance. These techniques could be especially important for women in the luteal phase. Practice cooling throughout longer runs and races by having cooling tools on hand, such as arm sleeves to pack with ice and neck bandanas to dip in cold water. And use every sprinkler for some extra cold-water immersion!
Supplement with a Sodium Drink
According to the Journal of Applied Physiology, pre-exercise sodium-loading aids fluid balance and endurance for women exercising in the heat. A female athlete in her luteal phase should try pre-loading a little more than usual with a sodium-based drink. Check out Nuun Sport tablets or Hammer Nutrition’s Race Day Boost.
Supplement with Carbohydrates
Focus on carbohydrate consumption during long runs and races by consuming approximately 40-45 grams of carbohydrates per hour. Easily digestible carbohydrates will ensure blood sugar levels stay stable so performance is not hindered. Hammer Gels, Sport Beans, Huma Gels, and other easily packable carbohydrate sources should be a regular part of training, especially during the luteal phase.
Recover with Carbs AND Protein
To counteract the breakdown of proteins during the luteal phase, protein consumption needs to be prioritized to promote recovery. Aim for 20-30 grams of protein along with carbohydrates from whole food sources within 30 minutes of training.
There you have it. You’ve completed your Anatomy lesson for the day, and learned how hormones impact running performance and more importantly, how to not let them impact your running training! If you have questions about this or other issues related to your running performance, we encourage you to contact us at RunFit MKE. After all, we ladies need to stick together!
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