Don't count on your period to burn more calories - here's why burning more calories on your period is mostly a myth

periodcaloriesburn — Research is still inconclusive on whether or not you burn more calories on your period.
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A myth persists that people burn more calories during their period, but experts say the number of calories burned during menstruation is not significant.
People may burn more calories in the luteal phase of their cycle, which is the time between ovulation and the start of your period.
Fluctuations in your metabolism are normal and depend on a variety of factors, such as age and activity level, not just your menstrual cycle.
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A myth persists that people can burn more calories while on their period, but health experts say the number of calories burned during menstruation is more nuanced.

Jodie Horton, MD, an OB/GYN based in Washington, DC and professor at Georgetown University, says calories burned during your cycle are affected by individual factors such as age, diet, and daily activities.

“It makes it difficult to get a definitive answer on how the menstrual cycle affects metabolism. Some women will burn more calories, whereas some will notice no difference,” says Jodie Horton, MD, an OB/GYN based in Washington, DC and professor at Georgetown University

Learn more about how your period and other phases of the menstrual cycle can affect your calorie burn.

Do you burn more calories on your period?

There’s little to no solid evidence that people burn more calories while menstruating.

Although many people think about burning calories in the gym, most calories burned happen during normal daily activities like breathing and digestion. And the number of calories you burn each day largely depends on your metabolism:

Resting metabolic rate (RMR) is the total number of calories your body burns at rest to perform basic functions such as breathing, blood circulation, and brain functions.
Basal metabolic rate (BMR) is the number of calories needed by your body to stay alive.

The terms BMR and RMR are often used interchangeably, Horton says, and they are mainly affected by age, diet, and daily activities - not menstruation.

Some small studies have indicated that RMR is affected by the menstrual cycle. One small 2015 study indicated that if women experience an increase in RMR during their cycle, it's before their period, not during menstruation.

You may burn more calories in the two weeks before your period

There is some evidence that people might burn more calories in the luteal phase of their cycle, which is the time between ovulation and the start of your period, says Alyssa Dweck, MD, a gynecologist in Westchester County, New York.

A 2020 review found that women experience a "small but significant" increase in RMR during the luteal phase. However, the review also said more research is needed to understand this phenomenon.

Dweck says that it makes sense that women would burn more calories during the luteal phase, when estrogen surges. "Theoretically this would occur during the luteal phase due to enhanced estrogen levels at this time," says Dweck.

Having too little estrogen has been linked to metabolic issues and obesity in menopausal women, which is why she says increased estrogen could be tied to higher RMR. Increased estrogen has also been linked to improved exercise performance, and exercise can boost your RMR.

"This increase in estrogen helps with muscle building, tolerating pain, faster recovery time, and more stamina," Horton says. "This may indirectly increase metabolic rate through the development of muscle and calories burned."

Exercise and healthy eating are important throughout your cycle

Many people experience fluctuations in their appetite during their menstrual cycle. A small 1996 study found that people who had an increased RMR during their luteal phase saw their calorie burn increase an average of 12%. A person would need an additional intake of 100 to 300 calories per day to offset that, Horton says.

However, she cautions that other research has shown "the small changes in metabolic rate that occurs during the luteal phase is not enough to significantly increase caloric burn or require an increase in caloric intake."

Though some women might have slightly better endurance at certain points during their cycle, you shouldn't expect to see a big difference in calorie burn in relation to where you are in your cycle.

"Although exercising is always recommended, there is no data to prove that you will burn more calories when exercising during your period," Horton says.

Despite that, Dweck recommends that women continue to work out during their periods.

"Exercise has benefits for PMS, cramps, water weight retention, and [blood] flow," she says. "Endorphins, which are feel-good chemicals secreted in the brain during exercise, contribute to wellbeing during PMS time."

She suggests that people aim for the recommended 150 minutes of exercise a week throughout their cycles.

Insider's takeaway

The hormonal fluctuations that happen during your menstrual cycle can affect how you feel physically and mentally. Although they might have a small effect on how many calories you burn, they won't have a major impact, according to both Dweck and Horton.

Fluctuations in RMR are normal and depend on a variety of factors, such as age and activity level, not just your menstrual cycle. Dweck says people should stick to their normal, healthy eating and exercise habits no matter their menstrual cycle phase.

"I recommend a regular exercise regimen as a lifestyle decision. The menstrual cycle will occur," she says, "and metabolism will vary day to day regardless."