Women Want To Know: Do You Burn More Calories While On Your Period?

November 23, 2021

Here’s a fun fact that may make you oh-so-glad to see “Aunt Flo”: you might burn more calories when you’re on your period. Seriously. So how can we capitalize on that period of every month that is always such a pain?

There’s a lot going on in your body when you start your period. Hormones are fluctuating, making you crave all the sweet and salty things. You’re probably carrying some extra water weight, your boobs hurt, and you’re making more trips to the bathroom than you care to admit. What’s there to be excited about?

A lot, actually. Especially if you’ve got fitness on your mind.

There’s research to support the idea that you burn more calories when you’re menstruating, even when your body is at rest. For example, in one study of 19 women, scientists took resting metabolic rate (RMR) measurements at least three times a week during a full menstrual cycle. Eight of the 19 subjects went through a second round of measurements during the following cycle. The study found that RMR isn’t stable in all women.

Understanding how your cycle affects RMR can help you optimize your physical well-being. Here’s what you need to know about your menstrual cycle’s effect on resting metabolic rate and how you can make it work in your favor.

Reviewing the Research

While studies on RMR and the menstrual cycle have been somewhat limited, the research we do have paints a positive story.

For starters, the Public Library of Science analyzed 30 studies on the menstrual cycle’s impact on RMR published from 1930 to 2019. Aggregating the data of these studies, researchers found that there is a small but significant RMR increase during the luteal phase of the menstrual cycle. This phase starts after ovulation and lasts until the first day of your period, spanning between 12 and 14 days.

During this time, your body produces more progesterone, which triggers your uterine lining to thicken. If you’ve ever noticed that you feel moody, sluggish, and full of brain fog on the days leading up to your period, you’re not imagining things. You’re dealing with tons of PMS symptoms, and your hormones (particularly a high level of progesterone) are key culprits.

However, the studies reviewed by the Public Library of Science revealed that patterns in RMR differences vary. This means that changes in RMR can depend on the individual. Methodology in testing is important, too: researchers note the need for testing during the same part of the cycle each month.

Another study by the British Medical Journal found variations in RMR across the menstrual cycle. For some, changes in RMR were just 1.7%. For others, they were as much as 10%. This reinforces the idea that RMR changes can vary by individual. However, in cases where the RMR increase was most significant, those women experienced a higher calorie burn during their periods.

Last but not least, the European Journal of Nutrition found that appetite and cravings increase during the luteal phase. There’s a lot of truth to the “periods and chocolates” tropes in pop culture. If you ever find yourself stuffing yourself with cupcakes, potato chips, or other sweet or salty favorites, even if you don’t normally consume those things at any other time of the month, it’s because your body simply can’t resist.

According to the European Journal of Nutrition study, one possible cause of these cravings is an increased energy demand during this time. A higher RMR typically translates to higher energy needs. Your body may be burning more calories, even if just slightly. This means it’s going to need more fuel for the fire.

So what does all of this mean for you? The simple answer is that you can find ways to make the most of your own RMR changes throughout your cycle. You don’t need to throw on a lab coat and test your RMR three times a week to do this. You just need to pay attention to your body and understand the various phases it goes through during your menstrual cycle. Knowing these phases can help you figure out what’s happening and why, such as why you suddenly want pancakes for dinner or why you just don’t feel like lacing up your running shoes. From there, you can decide the best path forward.

Using the Conclusions

We need more evidence before we can confidently say that exercising during high RMR phases will burn more calories for every woman. However, that doesn’t mean there aren’t benefits to gain. Here’s how to apply the above findings to your daily life:

Anticipating Your PMS Symptoms

Tracking your menstrual cycle can help you eat right and stay active by anticipating potential symptoms that impact energy levels and wellness. We mentioned that during the luteal phase, for example, PMS symptoms abound. You might feel more tired, moody, and hungry. If you’re tracking your menstrual cycle, you can pinpoint why you feel this way—your hormones are causing temporary changes.

During the first half of your menstrual cycle, such as when you get your period and on the days leading up to ovulation, you may feel more energetic. The increased estrogen creates a spike in energy. You may feel more productive and eager to tackle your to-do list or a HIIT workout.

Use a period tracking app like Flo, Clue, or Cycles to see at a glance where you are in your cycle. Knowing the different symptoms you’re likely to experience during each phase can help you plan ahead when it comes to fitness and nutrition.

For example, when energy levels are likely to be low, you can plan on restorative movement exercises that don’t require the off-the-walls vim and vigor of a toddler.

Linking RMR with Exercise

Exercise poses tons of health benefits, including increasing your energy levels. That’s a huge perk when PMS symptoms come knocking, even if cramps, moodiness, and tiredness are slowing you down.

If you need a little pick me up during the luteal phase when you’d rather be sitting on the couch instead of doing laps around the track, exercise anyway. It takes a little extra push to get going. But higher calorie burn or no higher calorie burn, working out can still do wonders for the way you feel, both physically and mentally. Some exercise (and calorie burn) is always better than none and may help to ease period symptoms such as cramps.

Connecting RMR with Nutrition

Based on the research regarding appetite and PMS, we can use what we know about our bodies to our advantage during the luteal phase, too. For example, you can eat small, frequent, protein-rich meals to boost energy when your appetite increases. Protein is filling and may help to curb your sweet cravings. If you’re tracking your period, you can start stocking up on protein-rich foods around day 14 or so since your luteal phase will be just beginning. Having enough healthy foods on hand and staying hydrated can stop you from reaching for the sweet or salty stuff.

It’s not just the calories that make these foods a less-than-desirable choice. Sugar can cause your energy to spike, then drop quickly. Your energy levels are already low, and the last thing you want is to feel even more tired after giving in to your cravings.

That said, it’s okay to treat yourself every now and then. Don’t feel guilty if it’s chocolate chip cookies for dinner and dessert one night.

What You Can Do Next

Although the increase and decrease in RMR during the various phases of the menstrual cycle are probably too small to make a fitness difference for most women, the statistical difference could affect tracking if you are using this metric to meet your goals. For this reason, it's smart to do RMR testing at the same time in your cycle each month.

Everybody (and every body) is different. As you undergo RMR testing, you can compare your results week by week and month by month to see the effects on your body.

Fitnescity offers and recommends RMR testing as part of a comprehensive weight management strategy. Whether you need to gain, lose, or maintain your weight, understanding your caloric burn at rest can help you better understand your nutritional needs from an energy standpoint. And because RMR can vary based on a person’s menstrual cycle and other factors like age, weight, ethnicity, muscle and fat composition, and more, RMR testing can give you the most accurate insights into your metabolism.

Find a Fitnescity location for RMR testing near you.