Are chills and fatigue a part of your monthly cycle? If you feel like you're coming down with a bug every time your period rolls around, you may be one of many people who experience "period flu." While this collection of symptoms is not an official medical condition, the discomfort period flu causes is very real.
It's hard to say how many people get period flu, but the US Department of Health & Human Services reports that more than 90% of menstruating people experience PMS symptoms each month. People in their 30s are most likely to experience severe symptoms, but they can crop up at any age. We talked to two doctors to learn more about the symptoms of period flu and what you can do to relieve them.
Period flu symptoms
Typical period symptoms include cramping and lower back pain. However, period flu symptoms can begin to mimic virus symptoms. Dr. Jennie Stanford, an obesity medicine physician and medical contributor for Drugwatch, explains: "Fatigue is the chief symptom. There may also be changes in bowel habits, like diarrhea or constipation, that occur frequently in and around menstruation." The doctor says you may experience muscle aches and pains as well.
Additional symptoms can include:
- Brain fog
- Fever-like chills
- Dizziness
- Joint pain
- Water retention
The good news is that the period flu isn't actually viral or contagious. Dr. Navya Mysore, medical director of women's health at Nurx, said, "The period flu is related to hormonal changes after ovulation."
Still, between the aches and stomach troubles, it's easy to see why you may mistake the period flu for an actual flu.
Is it period flu, the flu or COVID?
When muscle aches and stomach troubles hit, you may immediately assume you caught something at a social event. But Mysore recommends tracking your flu-like symptoms if they appear frequently in a cyclical pattern.
"If your symptoms are coinciding with your period and you're noticing this happening in a cyclical fashion, it's probably related to hormonal changes giving you flu-like symptoms," she said. "If you have the flu or COVID, your symptoms are going to hang around for a little longer and you usually feel more sick."
As for symptoms more associated with viruses than period flu, Mysore said, if it's the flu or COVID, "you'll generally have a higher fever (101-102ºF), sore throat or congestion."
A normal temperature is 98.6ºF, but can vary and can change for many non-infection reasons. The Infectious Diseases Society of America defines fever as a temperature of 100.4ºF sustained for over one hour or a single temperature of 101ºF.
You're more likely to have a virus if you experience "cough, sore throat, nasal congestion and nasal drainage," Stanford said. If you also have shortness of breath, diffuse body aches or a loss of taste or smell, COVID may be behind your malaise.
If you're unsure of why you feel bad, Mysore recommends that you purchase a COVID test, go to urgent care or make an appointment with your primary care physician to test for COVID and the flu.
Period flu causes
Period flu is cyclical because it is caused by the hormones associated with egg release or ovulation. In the menstrual cycle, there are four phases:
- Follicular (pre-egg release)
- Ovulatory (egg release)
- Luteal (post-egg release)
- Menstruation (also known as a period)
Mysore explained the hormonal causes in detail: "Estrogen and progesterone, which help regulate your cycle, surge before and after ovulation, respectively. If you don't get pregnant, you have a decline in hormones." She says this is when period flu and PMS symptoms often occur, right before you start a period. In technical terms, this is in the luteal phase.
"Right before your period, the uterus releases hormones -- prostaglandins -- which contract the uterus and can result in pelvic cramping, lower back pain and a low-grade fever," she said.
Stanford agrees that hormone fluctuations, especially the drop in progesterone, are to blame for the majority of period flu symptoms. She adds that "blood loss, especially in [people] with iron deficiency; changes in sleep patterns; and higher levels of inflammation" could also contribute.
How to treat period flu at home
If you're feeling down and out with chills, aching muscles and other period flu symptoms, you don't have to suffer through them. There are over-the-counter measures that can improve your condition until you're on the other side of your hormone swing.
When asked about how to treat period flu, Mysore says she recommends "everything I would typically recommend for PMS: pain relievers, like NSAIDs, to reduce cramps and body aches and a warm compress for body aches."
It's also important to rest and hydrate, according to Stanford. She adds that good nutrition may also help treat some symptoms. In some cases, the doctor advises that hormone therapy, selective serotonin reuptake inhibitors (SSRIs) or iron supplementation may be recommended by your physician to help you avoid serious symptoms in the future.
How to prevent period flu
Mysore says that hormone fluctuations in your cycle can be exacerbated by stressors in your life. "If you're lacking sleep, not eating well, not exercising -- often period symptoms will be worse," she said. The following tips may help you prevent severe period symptoms in the future:
- Get regular exercise. Exercise can release endorphins, lower stress and ultimately reduce your PMS and period flu symptoms. If you're not typically active, try starting with low-impact exercises like walking or yoga.
- Stop smoking. A 2008 study from the American Journal of Epidemiology found that smoking may increase the severity of PMS symptoms. This is especially true of younger people.
- Eat a well-balanced diet. Stanford notes that "optimal vitamin and mineral levels" may mitigate some period flu symptoms. Committing to a well-balanced meal plan may offer some relief.
- Try meditating. Meditation can reduce stress and help you get better sleep. Mysore recommends dipping your toe in the practice if you are experiencing regular period flu.
When to see a doctor for period flu
When you can't seem to reduce your symptoms at home, it may be time to seek professional help. As for when it's time to see a doctor, Mysore said, "this is completely up to the individual -- there is no threshold on when you should wait." However, she notes that if period flu "is happening consecutively and having an impact on your life, check in with a primary care doctor."
Some doctors may recommend medication to treat your symptoms. Mysore says, "If the pain is happening every single month and taking away from your ability to function, it might be time to talk to your provider about birth control, which can help reduce PMS symptoms and pelvic cramping."
Stanford tells us that severely heavy bleeding, severe depression and mood changes are all reasons you may want to schedule an appointment with your doctor. She adds that ongoing fatigue that limits activities of daily living and dehydration are also reasons to check in.
Related conditions
Other common conditions may be mistaken for period flu. If over-the-counter pain relievers and lifestyle changes don't alleviate your symptoms, you may want to consider whether the following diagnoses apply to you:
- Ovarian cysts. These fluid-filled sacs can grow on or in the ovary. You may not notice symptoms at first. However, large or twisted cysts can cause nausea, back pain, abdominal pain and gastrointestinal issues.
- PMDD. Premenstrual dysphoric disorder is diagnosable and typically happens the week before a period. Common symptoms include mood swings, joint pain, brain fog and insomnia. Generally speaking, this is a very severe form of PMS.
- Gastroenteritis (stomach flu). The stomach flu may lead to vomiting, diarrhea, fever and abdominal cramping. If your symptoms occur just after a period, it may more likely be the regular flu and not the period flu, especially if you have a high fever. This typically lasts only a few days and is not cyclical.
- Migraines. The period flu can cause headaches, but some patients also have migraines outside of their menstrual cycle. Even if your headaches are triggered by your cycle, migraine medication may help.
The bottom line
Period flu is not an official medical condition, yet many people with periods experience it. If your PMS phase goes beyond cramps and into muscle aches and body chills, you may be dealing with period flu. Luckily, some ibuprofen and plenty of rest may be all it takes to wrangle your symptoms. Doctors also recommend staying hydrated, resting and engaging in physical activity to help mitigate your discomfort. When in doubt about what's happening with your body, schedule an appointment with your doctor to discuss your symptoms.