“I always assumed that your period would doom your race,” says the New Hampshire-based athlete and writer. “I expected that fatigue and cramping would be detrimental to my performance.”
What Canney learned later, however, was that racing during a menstrual cycle is actually ideal because a woman’s estrogen and progesterone levels are at their lowest, making their physiological impact minor. Turns out this can be an ideal time to go for that personal best.
There’s a good deal of urban myth and old wives’ tales that surround a woman’s cycle, and this extends into the athletic arena. “There’s a dearth of information into the role hormonal fluctuations play with regard to athletic performance,” says Stacy Sims, an exercise physiologist and nutrition scientist at the University of Waikato in New Zealand. “The result is that women have not been equipped with tools to manage these cyclical ups and downs.”
This speaks to the larger issue of scientific research that focuses more on males, particularly in regard to sport. A 2014 analysis found that only 3 percent of studies on sports performance between 2011 and 2013 even involved women. That’s beginning to change, however, as a small group of researchers digs into the issues female athletes face because of their cycles.
“There is a growing number of sports scientists who are including more women as their subject groups,” says Clare Minahan, an associate professor at Griffith University’s Sports Physiology and Performance School in Australia. “This leads to more consideration of cycles in response to exercise and training adaptations.”
Understanding a cycle
For instance, during ovulation, about 14 days before a period begins, estrogen will rise and hit its highest level. This may impact metabolism and the body’s ability to store carbohydrates. which could negatively affect someone who is tackling a longer endurance event, Sims says.
Minahan recommends, though, that before taking any steps, athletes get to know their bodies through each phase. Some women, for instance, “during ovulation . . . will also have elevated oxidated stress, or inflammation,” so carbs would not be advised, she says. “The research is not quite there to make blanket statements, so each woman needs to work it out on an individual level” based on her own experience.
In the early part of the luteal phase, which comes after ovulation but before your period starts, estrogen remains high and progesterone joins it. Bloating and fatigue tend to rule the day at this stage. Heart rate may increase, and performing in heat and humidity become more difficult because of an elevated core temperature. All are factors to consider when looking at racing calendars.
Women athletes can choose not to schedule big events during this phase, or as Sims recommends, manage it. “This is a phase where your central nervous system fatigue is high and progesterone levels contribute to sodium loss,” Sims says. “So you can manage that by increasing electrolyte intake, for instance.”
Minahan says that she encourages women athletes to track their cycles and training and combine the two, then works to develop an individualized approach to nutrition and racing. “A large number of athletes just don’t do that,” she says, but it provides a tool “that’s very powerful.”
After her unexpectedly positive experience at the world championships, Canney went back and looked over past races and outcomes. She then tracked her cycles and could see correlations: Most of her best races lined up with times she was having her period. She has used this information to improve her training and performance, including adding a period track app to help with the process.
“It’s been a mental shift for me,” she says. “Now that I’m informed, I realize that I’m in control.”
One such app, FitrWoman, garnered a lot of media attention after the U.S. women’s national soccer team revealed players had used it to help improve their training before their World Cup victory.
Created by Georgie Bruinvels, an exercise physiologist with sports research company Orreco, the app uses information drawn from an extensive literature review to help women track and manage cycles. Scott had Bruinvels consult individually with the soccer team’s players months before the World Cup began.
“When women understand why they experience different symptoms at different phases in their cycles, they can adjust their approaches to nutrition and hydration,” Bruinvels says. “We believe that female athletes can perform on any day of their cycles by making the right changes for those particular hormonal variations.”
The app provides both an explanation of the fluctuations occurring at any given phase of a woman’s cycle as well as tips and recipes to help combat symptoms that might have negative impact on performance. There are several other period tracking apps on the market, though most aren’t focused on athletic performance.
Bruinvels says that like many athletes, the women’s national soccer team members believed playing during their period would lead to poorer outcomes and were surprised — and pleased — to see how individualized sleep, hydration and nutrition strategies made a difference.
Minahan says that information about hormonal fluctuations and their impact on performance is one of the most promising aspects of the emerging sports research involving women. “So many women have false perceptions about the impact of their periods and have never questioned those ideas,” she says, and that affects their attitude about what happens to their bodies throughout their menstrual cycle and about what they can accomplish physically. “Getting the correct information out is so important.”
Canney says she is a better prepared athlete now, and the information has definitely changed how she thinks about her racing and training. Now, she says, “If I have a bad workout during ovulation or in the luteal phase, I know it was likely due to hormones and I cut myself some slack.”