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Managing The Menstrual Cycle

Managing The Menstrual Cycle Run Tri Bike Magazine Dr Leah Roberts

The Female Athlete’s Guide To Managing The Menstrual Cycle

“Complete abstinence from activity in sport is absolutely imperative in the menstruating woman…no sportsman would ever dream of competing with a wound in his vital organs!” – Dr. Stephen Westmann, 1939

The advice about period and exercise may be from 1939, but the sentiment is still mistakenly believed by many today – women can’t (or shouldn’t) train and race while on their period. Certainly, Aunt Flo can throw a wrench in a female athlete’s plan, unleashing a barrage of unpleasant symptoms – fatigue, cramping, bloating, headaches, GI distress, and heavy flow – but that doesn’t mean race day is doomed. It doesn’t mean a woman is competing with a wound in a vital organ (we’ll get to that in a second). And it definitely doesn’t necessitate a complete absence from exercise. We asked Dr. Leah Roberts of SteadyMD (and 9-time Ironman finisher) about how female athletes can best train and race during “that time of the month.”

A Menstrual Cycle Overview

Though the “period” is the most noticed aspect of the menstrual cycle, it’s not the only part of it. The word “cycle” refers to the monthly sequence of hormone fluctuations – specifically, the hormones estrogen and progesterone – in preparation for releasing an egg for fertilization. These hormones also trigger a thickening of the uterine lining in anticipation of hosting a fertilized egg (which will eventually become an embryo, then a fetus). If the egg isn’t fertilized, however, the uterus sheds the lining – also known as a “period.” Though it presents as bleeding, it’s actually not a wound – so it’s safe and healthy to proceed with normal activity and exercise, including swim-bike-run.

Hormonal Impact on Athletic Performance

Fluctuations in hormones don’t just affect the reproductive organs. Female athletes may experience changes to their athletic performance, depending on where they are in their cycle.

“Hormones play a role in fluid regulation and have effects on blood volume,” says Roberts. “During the peak of estrogen and progesterone, plasma volume is the lowest, which reduces cardiac input.” In other words, your heart rate will be elevated, despite putting in the same amount of effort as other stages of the cycle. Exercise may feel harder, and heart-rate based workouts and race plans may need to be adjusted to allow for this variation in heart rate.

Hormone levels also affect core temperature (making it harder for the body to cool itself through sweat), can impair hydration levels, and impede muscle recovery from workouts. For a detailed look into how hormone levels affect female athletes, as well as instructions for adapting training to various phases of the menstrual cycle, Roberts recommends the book Roar by Stacy Sims, PhD.

Prepping For “That Time of the Month”

The biggest stressor for a female athlete might not be the race itself, but realizing that a period will coincide with race day. Each woman experiences a different set of symptoms (and even individual variability from month to month), but Roberts suggests tracking your cycle and related symptoms as part of a training log. This will allow you to notice patterns in your cycle as well as what symptoms you’ll need to manage.

The best cure for menstrual symptoms is a healthy dose of prevention, says Roberts. Taking steps before the period begins can help minimize (and in some cases, even eliminate) certain symptoms.


Roberts says tackling cramping 5 to 7 days prior to the onset of menstruation is key. Evidence has found that supplementing 400 milligrams of magnesium oxide, taken in conjunction with 1 gram of Omega 3 fatty acids, can reduce the severity of cramping.

Bloating & GI Distress

Taking a simethicone medication, such as Gas X, in the days before onset can serve as a preventative measure to bloating and GI distress. There is also some evidence that the magnesium-Omega 3 combination utilized for cramping may also reduce symptoms of GI distress associated with the menstrual cycle.


Headaches associated with the menstrual cycle can often be tied back to hydration levels (remember, hormone fluctuations impact hydration), so staying on top of water intake is a critical element for preventing headaches.


If you’re expecting your period to coincide with race day, Roberts recommends increasing sleep time in the week leading up to the race and even cancelling workouts if needed. “If it’s a taper week, remember that less training is more. It’s okay to take an extra rest day.”

Heavy Flow

“If your menses is heavy enough to cause anemia, it might be a good idea to consider taking a birth control pill or having an IUD implanted, which can reduce or eliminate heavy periods,” says Roberts. “Talk with your OB/GYN about the options available.”

Going With The Flow on Race Day

Though it may seem like a good idea to take a pain reliever on race day to stop cramps in their tracks, Roberts says this should be done carefully: “If cramping is severe, take acetaminophen (Tylenol) only. NSAIDs such as ibuprofen (Advil, Motrin) and naproxen (Aleve) should be avoided, as they are metabolized by the kidneys, which are particularly taxed during a race, especially if you fall behind in hydration.” In longer events, such as a half or full Iron-distance triathlon, NSAIDs can put an athlete at risk for a condition known as rhabdomyolysis, a breakdown of muscle tissue that can cause kidney damage and failure.

Fluid collection methods are a personal choice that depends on a variety of factors. However, Roberts recommends avoiding pads, which will be ineffective during the swim and while saturated with sweat. Instead, a tampon or intravaginal cup will be a more effective method.

During longer-distance events, women may need to change a tampon. To minimize the risk of bacterial infection, Roberts recommends using a tampon with an applicator as well as applying hand sanitizer before and after changing.

Can’t I Just Avoid This Altogether?

Yes and no. A woman’s menstrual cycle can be one measure of health – if a period appears at regular intervals, it usually means things are humming along nicely. Missed periods or changes to your symptoms may signal something is up, like pregnancy or athletic amenorrhea.

But in healthy women, there are options for shifting the timing of menstruation to a week that doesn’t coincide with a race. “Taking birth control pills can help you modulate your period and when it arrives,” says Roberts. “I would discuss this first with your OB/GYN several months before the start of the race season.”

You can read our Real Life. Real Talk. series on the menstrual cycle by Angela Naeth in the links below:

Leah Roberts Emergency Medicine Physician Run Tri Bike Contributor

Dr. Leah Roberts is a board-certified, Emergency Medicine physician with a special interest in female endurance athletes and preventative primary care. She holds a BA in biochemistry from Barnard College, a MS in Nutrition from Columbia University and a MD from Temple University School of Medicine. She did her her Surgical internship at Temple University Hospital and her Emergency Medicine residency at Cooper University Hospital (Camden, NJ). Dr. Roberts currently splits her clinical time between practicing in the Emergency Room at Robert Wood Johnson University Hospital at Somerset and and as a primary care physician with SteadyMD. Dr. Roberts is a regular contributor to and a ten-time IRONMAN (IM) finisher (PR 9:47) with an amateur win at IM Lake Placid 2018. She is also a four-time IM World Championship qualifier, a three-time Olympic Distance World Championship competitor and an IM 70.3 World Championship qualifier.

Dr. Roberts is currently the team physician for IRACEALIKEGIRL Endurance Team.