If you’ve ever struggled through a workout while menstruating you might have wondered if you should have just stayed home and snacked on bread sticks. But there’s no harm in working out on your period.
“There aren’t a ton of reasons to skip your workout on your period,” says sports medicine specialist Dr. Natasha Trentacosta, M.D., an orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles. “There are actually more reasons not to skip it.”
Read on for plenty of reasons to exercise during that time of the month.
First, Here’s What’s Going On In Your Body During Menstruation
The menstrual cycle has four phases: the menstruation phase, follicular phase, ovulatory phase, and luteal phase.
Your menstrual cycle starts on the first day of the menstrual phase, which is when—if you’re not pregnant—the lining of the uterus sheds out through the vagina, explains Alyssa Dweck, M.D., OBGYN, author of The Complete A to Z for Your V and INTIMINA sexual health expert. In addition to the visible happenings (blood), during this time, your progesterone and estrogen levels drop to their lowest points in your cycle, she says. Meanwhile, your levels of prostaglandins (chemicals produced by the body during menstruation and when injured) soar.
So, What Does This Have To With Exercise?
The hormones affected by your cycle govern literally every aspect of your life, including sleep, mood, stress levels, libido, and—yep, you guessed it—your exercise routines.
Low estrogen and progesterone hormone levels, for instance, are associated with low energy levels, says Dweck. If you’ve ever felt like you’re literally crawling to the gym during your period, this is why.
And about those increased prostaglandins? “Prostaglandins increase inflammation throughout the body,” says Trentacosta. This can contribute to you feeling especially stiff and inflexible while bleeding.
Read More: 4 Ways You May Be Negatively Impacting Your Hormones Without Even Realizing
During menstruation “vasoconstriction”, or narrowing of the arteries, can also occur in the uterus, adds Dr. Kecia Gaither, M.D., M.P.H., FACOG, Director of Perinatal Services at NYC Health + Hospitals/Lincoln. Sometimes this results in ischemia (inadequate blood supply to the uterus) or uterine necrosis (death of some of the uterus’ cells). With both, it’s a recipe for cramping, nausea, and headaches, she explains. Doing anything—let alone working out—while cramp-ridden often feels impossible.
The sum of all of these parts: During your period, your desire to work out may take a hit.
Are There Any Risks To Exercising While On Your Period?
Working out while feeling sluggish, stiff, or crampy is no fun. According to experts, though, there are no actual health risks.
You may, for example, have heard a rumor that being on your period increases the chances that you’ll tear your ACL. However, this simply isn’t true. “There is no research suggesting that being in your menstrual phase increases the risk,” says Trentacosta.
This rumor began when some data suggested you may be more likely to tear your ACL during your ovulatory phase, she says. (Note: ovulatory, not menstrual). One study published in the Journal of Athletic Training, for instance, suggests that females are at significantly greater risk of ACL injury during the preovulatory phase than the postovulatory phase.
That said, “there are just as many studies showing no connection between cycle and ACL injury risk,” Trentacosta says. In fact, a 2017 Orthopedic Journal of Sports Medicine review on the topic concluded that “the overall strength of this evidence is low.”
Another common misconception: that it’s a bad idea to deadlift while menstruating. While anecdotal, Trentacosta says patients have reported that they can’t pull as much weight during their menstrual phase.
Read More: 3 Ways To Improve Your Deadlift And Crush Your Next PR
Thing is, it’s not an actual loss of strength at play here. Instead, she suspects it’s a change in perceived exertion. Research has shown that some women report greater rates of perceived exertion while menstruating than during other parts of their cycle. In other words, the bar isn’t any harder to pull on your period than usual; you just think it’s heavier.
Luckily, “things like warming up, doing hamstring and glute activation exercises, prioritizing sleep, hydration, and stress management can all counter this, so that your perceived exertion doesn’t change too much,” says Trentacosta.
The Case For Exercising On Your Period
Though working out on your period may not always appeal much, there are plenty of reasons to get moving during your time of the month.
1. Exercise Is Good For You!
“Exercise is important throughout your lifetime—including when you’re menstruating,” says Trentacosta. Regular exercise, after all, has been linked to reduced risk of heart disease, improved blood sugar and insulin levels, better brain health, and more.
Of course, if you want to skip your workout one or two days, that’s fine. “You’re not going to ruin your progress by ditching the gym for a few days,” Trentacosta says.
Assuming you don’t have uterine fibroids, endometriosis, or adenomyosis (all conditions that can make menstruation beyond painful), you don’t need to take every single day of your period off. “It just doesn’t make sense to take a full week off of exercise if you don’t have to,” she says.
2. It Can Help Reduce Pain
In addition to gifting you with major post-workout bliss, “endorphins also have an analgesic effect,” explains Gaither. Basically, these feel-good hormones function as natural painkillers—and can reduce period-related pain.
According to a 2017 study published in Neuropsychopharmacology, adults who engage in an hour of high-intensity interval training experience a significant increase in endorphins compared with those who engage in less-demanding activity.
So, unless your symptoms are making it too difficult to hit your workout hard, opt for a HIIT class over a strength or yoga session for maximal pain relief.
3. You May Actually Make Greater Strength Gains
Turns out, low estrogen levels during your period have one serious workout benefit: They may set you up for better strength-training results. One small 2016 study, for example, suggests that the menstrual and follicular phase of your period may be the best time to strength train, specifically because that’s when estrogen levels are lowest.
For the study, researchers split women into three groups: those who worked leg five times a week during the first two weeks of their cycle, those who did so during the last two weeks of each cycle, and a control group. After nine months, the women in the first group experienced greater improvements in jump height and lean lower-body mass than those in the other two groups. This ultimately leads the researchers to conclude that the first two weeks of your cycle are the best time to make power and strength gains.
4. Reduced Bloating
Raise your hand if your period leaves you feeling like pufferfish. Good news: “Exercise can help reduce water retention (through perspiration), and as a result can help minimize uncomfortable bloating,” says Dweck.
Just note that dehydration can increase muscular cramping, she says. When you’re menstruating, inadequate water intake (or excess water loss) can actually make cramps worse. So be sure to stay hydrated as you work out.
The Bottom Line On Exercising On Your Period
Broadly speaking, most people can continue their regular exercise routines throughout the menstrual phase, Trentacosta says. After all, no conclusive scientific research shows that your body benefits from skipping the gym altogether. On the contrary, unless your symptoms are severe, working out will probably help ease period-related pain—not worsen it.
“Ultimately, it comes down to whatever feels best to the person menstruating,” says Trentacosta. “If you feel like going for a run, do that. If you feel like hitting the weights, have at it.” And, if it feels better to take a rest day, there’s nothing wrong with that, either. Remember: One or two days off won’t hijack your fitness goals.
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