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Female Fatigue & Low Energy: 19 Common & Little-Known Causes

Female fatigue can be caused by hormones, periods, pregnancy, or menopause. Lower your sleep debt and sync up with your body clock to boost your energy levels.
Written by
Jeff Kahn, M.S., Rise Science Co-Founder
Reviewed by
Chester Wu, MD, Rise Science Medical Reviewer
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We bring sleep research out of the lab and into your life. Every post begins with peer-reviewed studies — not third-party sources — to make sure we only share advice that can be defended to a room full of sleep scientists.
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Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.

Female Fatigue: Reasons & Fixes for Why You're So Tired

  • There are many causes of female fatigue and low energy. Common reasons include high sleep debt, being out of sync with your circadian rhythm, and hormone fluctuations during your menstrual cycle, pregnancy, and menopause. Other causes include stress, hormonal contraceptives, and medical conditions like thyroid issues or anemia.
  • To fight female fatigue, start by lowering your sleep debt and syncing up with your circadian rhythm. This can boost your energy levels and, if you’re still tired all the time, help you feel better while you address other causes.
  • The RISE app can help you do this and guide you through 20+ sleep hygiene habits to help you get the good night’s sleep you need for more energy.

Sometimes tiredness has no obvious reason and, even more annoying, sometimes fatigue persists day after day.  

Anyone can feel tired and sleepy, of course, but hormone differences mean women are more prone to sleep problems and the lack of energy they lead to, and things like periods, pregnancy, and menopause only add to your fatigue. 

Below, we’ll dive into the common reasons you may be feeling fatigue as a woman and how you can use the RISE app to get more energy. 

Heads-up: Tiredness and sleepiness aren’t the same thing. Tiredness is when you feel fatigued but might not be able to sleep. Sleepiness is when you could fall asleep, even during the day. Both can leave you feeling low on energy and not yourself, but your energy should improve after sleep if you’re experiencing sleepiness. Tiredness can linger even after a good night’s sleep. While we acknowledge the scientific distinction between being "tired" and "sleepy," we’ll use these terms interchangeably throughout this article, as they are often used synonymously in everyday language. However, we’ll make a specific note when we are focusing on one particular aspect of these experiences.

Disclaimer: The scientific literature uses gendered language when talking about female fatigue. We have used the terms “female” and “women” in this article, but this advice is for anyone who experiences fatigue and was assigned female at birth.

Advice From a Sleep Doctor

Advice From a Sleep Doctor

“There are many reasons for female fatigue,” says Rise Science sleep advisor and medical reviewer, Dr. Chester Wu, who is double board certified in psychiatry and sleep medicine.

“Hormonal fluctuations, your period, pregnancy, and menopause are just the start. Focus on getting as much sleep as you can to increase your energy levels. Getting out in natural light first thing in the morning and avoiding light before bed can help you fall and stay asleep.”

What Are the Causes of Female Fatigue?

More research needs to be done into female fatigue and women’s health, but here’s what we do know about why you might be feeling tired. 

1. High Sleep Debt

One of the most common causes of tiredness — for both men and women — is high sleep debt. Sleep debt is how much sleep you owe your body. It’s compared against your sleep need, the genetically determined amount of sleep you need. 

Many of us don’t know how much sleep we need, so you might not even realize you’re not getting enough sleep and wracking up debt. 

We don’t all need a simple eight hours of sleep a night. In fact, when we looked at the sleep needs of 1.95 million RISE users aged 24 and over, we found their sleep needs ranged from five hours to 11 hours 30 minutes. 

The RISE app can tell you how much sleep you need.
RISE users' sleep needs.

You might be feeling tired suddenly if you didn’t meet your sleep need last night, or feel tired even though you got enough sleep if you’ve got lingering sleep debt from previous nights. 

And it’s easy for women to fall short. Women are more prone to sleep problems (more on those soon), so may have lower sleep efficiency than men — they spend more time awake in bed. That means they need to spend longer in bed to get the sleep they need.

Plus, a lack of sleep may affect women in particular. A 2022 study found women felt sleepier during a night of sleep deprivation than men.

We found among RISE users, women, on average, have more sleep debt than men from parenting years, through menopause, and beyond. This may be why women feel more tired and like their energy levels are always low.

Age Who has more sleep debt?
18-23 Men
24-29 Same amount
30-39 Women
40-49 Women
50-59 Women
60+ Women
Overall Women

How do you know if you’re getting enough sleep? The RISE app can work out your individual sleep need and how much sleep debt you’re carrying each day. 

We look at whether or not women need more sleep than men here (spoiler: we don't know).

The fix: Lower your sleep debt by taking short afternoon naps, heading to bed a little earlier, or sleeping in a little later. We’ve got more advice on catching up on sleep here.

RISE app screenshot showing how much sleep debt you have
RISE can work out your sleep debt.

RISE users on iOS 1.202 and above can view their sleep need here and view their sleep debt here.

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2. Living Out of Sync with Your Circadian Rhythm

Your circadian rhythm is your body’s internal clock. When you’re out of sync with it, your mental and physical health take a hit, and your energy levels can plummet. 

You might be out of sync with your circadian rhythm if: 

  • You have social jetlag, or an irregular sleep schedule (which 87% of us do)
  • You work night shifts 
  • You’re living at odds with your chronotype — such as when a night owl forces themselves to be a morning person 

Again, this common, and often overlooked, cause of tiredness can make both men and women feel fatigued, but women may be more prone to it due to their fluctuating hormones. 

The combination of having sleep debt and being out of sync with your circadian rhythm can make the natural dips in energy that come as part of your circadian rhythm feel worse. That means you might feel more tired in the early morning and before bed, and have extreme crashing low energy levels in the afternoon. 

The fix: Check RISE for a prediction of your circadian rhythm to see when your body wants to wake up and go to sleep. Try to sync up your sleep schedule with these times and stick to it, even on weekends. 

RISE app screenshot showing energy dip and peak times
RISE predicts the timing of your circadian rhythm.

RISE users on iOS 1.202 and above can see their circadian rhythm on the Energy screen here

3. Sleep Disorders like Sleep Apnea and Insomnia 

A sleep disorder could be causing sleep debt to build up night after night. 

These include:  

  • Sleep-disordered breathing — like snoring or obstructive sleep apnea 
  • Insomnia 
  • Restless leg syndrome

Anyone can be affected by these sleep disorders, but female stages of life can bring them on. 

When girls first get their periods, there’s a 2.75-fold increased risk for insomnia. You might experience insomnia before your period, or heavy periods can trigger a drop in iron levels, which can cause restless leg syndrome. You might also develop sleep-disordered breathing during pregnancy and sleep apnea during menopause.

Women have higher sleep reactivity, which means their sleep is more likely to be affected when they’re stressed. They may ruminate on problems, making them more vulnerable to insomnia, and constantly changing hormones and sleep patterns make the sleep disorder more likely. In fact, insomnia is 40% more prevalent in women than men. 

4. Your Period and Menstrual Cycle 

Periods are another reason for low energy levels in females. 

A 2020 study found total sleep time, deep sleep, and sleep efficiency decreased, and sleep onset latency (how long it takes to fall asleep) increased when women were on their periods. 

It can be a vicious circle, too. Menstruation can cause sleep problems, but sleep problems can make period symptoms worse. 

Here’s how your period can cause low energy: 

  • Hormone fluctuations can make it hard to fall asleep: Low levels of estrogen and progesterone just before your period can prevent the sleep hormone melatonin from being released effectively, making it harder to fall asleep. 
  • Hormone fluctuations can change your sleep stages: Estrogen is linked to rapid-eye-movement sleep (REM) and progesterone increases non-rapid-eye-movement (NREM) sleep. 
  • Heavy bleeding can lead to iron deficiency anemia: This is when you don’t have enough red blood cells. The main symptom of iron deficiency anemia is fatigue. You may also get anxious about bleeding onto your bed sheets, which can keep you up, or you may have to get up during the night to change your pad, tampon, or menstrual cup. (Can you sleep with a tampon in? Technically yes, but we recommend tampon alternatives instead.)
  • Cramps can keep or wake you at night: Period symptoms like cramps, lower back pain, and bloating don’t make sleep easy to come by. 

You can learn more about why you’re feeling tired on your period and period insomnia here.

Hormonal birth control — like the pill or implant — is another common cause of female fatigue. It can also cause depression and sleep problems, which won’t do your energy levels any favors. You can learn more about how birth control makes you tired here.

The fix: Try breathing exercises to manage anxiety, gentle yoga to ease pain, and bullet-proof sleep hygiene (the daily habits that help you sleep) to make sure nothing else keeps you up at night. We’ve got more advice on how to sleep on your period here. 

5. Pregnancy

If you’re pregnant, this may be why you’re always tired and have no energy.

Progesterone increases in the first trimester of pregnancy, which can make you feel drowsy. You’re also likely to develop sleep-disordered breathing and insomnia during this time. 

Pregnancy symptoms — think heartburn, leg cramps, and back pain — can also make it harder to fall and stay asleep. 

Aside from sleep, morning sickness, anxiety about pregnancy, and carrying extra weight can leave you feeling drained during the day.

The sleep problems don’t end when your baby’s born, either. A 2019 paper states 50% of women with probable insomnia during pregnancy continue to have symptoms two years after giving birth. 

If you’ve had or are planning on having a c-section, you can learn how to sleep after a c-section here.

The fix: Improve your sleep hygiene to make the most of the sleep you can get. Get out in natural light first thing, and avoid light, caffeine, and intense exercise too close to bedtime. You can learn more about how to get energy when pregnant here.

6. Menopause   

If you’re a middle-aged woman feeling tired all the time, it might be due to menopause or perimenopause — the transition period before menopause.

One symptom of menopause is sudden crashing fatigue that can leave you feeling drained.

There are a few reasons for this: 

  • Fluctuating hormones (yet again): Declining estrogen and progesterone can increase anxiety, sleep-disordered breathing, sleep apnea, and how long it takes you to fall asleep. 
  • Menopause symptoms make it harder to sleep: Night sweats, weight gain, anxiety, depression, and an increased need to use the bathroom at night can all make it harder to meet your sleep need. General aging symptoms can also impact your sleep, and these tend to affect women more than men. 
  • Sleep apnea: Your risk of developing sleep apnea goes up with age and during menopause. It’s estimated 47% to 67% of postmenopausal women have sleep apnea. This can happen due to weight gain and hormone changes. 

We’ve covered more on why menopause makes you tired here.

The fix: Consider hormone replacement therapy, which can treat hot flashes, help you fall asleep, and decrease middle-of-the-night awakenings. You can learn more fixes for menopause sleep problems here.

7. Recovering from an Illness

Even if you don’t feel ill anymore, your body may still be fighting an infection or recovering from the sleep debt you built up while ill. 

There may be differences between men and women here too. For example, COVID fatigue can hit anyone, but research shows women are at a higher risk of COVID-related sleep disturbances and of developing long COVID, which can cause sleep disturbances and severe fatigue. 

The fix: Pay back sleep debt when you can. If you can’t get extra sleep at night, afternoon naps can help. You can learn how to get energy back after COVID here.

8. Stress, Depression, and Anxiety 

Stress, depression, and anxiety can cause excessive tiredness in anyone, but women are more prone to mental health issues. 

Women are more likely to have: 

The fix: Check out RISE’s breathing and relaxation exercises to soothe stress and anxiety before bed. We’ve covered more on how to sleep with anxiety here. 

RISE app screenshot showing relaxation session
RISE can guide you through breathing exercises.

RISE users on iOS 1.202 and above can go right to their relaxation audio guide homepage and get started here.

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9. Poor Diet 

Sugary snacks and simple carbs can spike your blood sugar levels. This is followed by a sugar crash, which can cause sudden fatigue shortly after. 

A large lunch can make women (or anyone) feel tired in the afternoon as it makes your natural afternoon dip in energy feel even worse. 

And diets high in added sugars, starch, and refined grains have also been linked to insomnia. 

Eating too close to bedtime can also keep you up at night. Check RISE for when you should have your last large meal of the day. 

The fix: Eat a balanced diet with complex carbs, proteins, fruits, and veggies to boost your energy levels and overall health and wellness. A healthy diet can help you keep your sleep debt low, too.

10. Nutritional Deficiencies 

Missing out on key vitamins and minerals can cause fatigue. And this may affect women more than men. 

For example, low iron is common if you have heavy periods and during pregnancy. And low vitamin B9 and iron levels during pregnancy increases your risk of developing restless leg syndrome, disrupting your sleep.

Nutritional deficiencies that cause fatigue include: 

  • The B vitamins: B2, B3, B5, B6, B9, and B12 
  • Vitamin D
  • Vitamin C 
  • Iron 
  • Magnesium 
  • Zinc

Beyond daytime fatigue, nutritional deficiencies can affect your sleep. 

Vitamin D deficiency can up your odds of sleep disorders and low magnesium is linked to insomnia. Low vitamin C, zinc, and vitamins B6 and B12 have also been linked to depression and anxiety, which may contribute to poor sleep.

The fix: A doctor can test you for nutritional deficiencies and prescribe supplements if needed. Eat a varied healthy diet to minimize your risk.

11. Too Much Caffeine or Drinking Caffeine Too Late in the Day

Caffeine can keep you up past bedtime and wrack up your sleep debt, and it can stay in your system much longer than you think (it could be 12 hours or more!).

When caffeine wears off, you may be hit with sudden fatigue. The more caffeine you’ve been drinking to mask growing sleep deprivation, the more crashing that fatigue will be when it finally wears off.

And it’s easy to build up a tolerance to caffeine, too, meaning when you have a cup less than you’re used to, you’ll feel sleepy. 

The fix: Avoid caffeine about 12 hours before bed. RISE can tell you when to have your last coffee each day

RISE app screenshot reminding you when to limit caffeine intake
RISE can tell you when to stop drinking coffee each day.

RISE users on iOS 1.202 and above can set up their limit caffeine reminder here.

12. Dehydration 

Even mild dehydration can cause fatigue, as well as disruptions in mood and lowered mental and physical performance. 

Hydration may also affect your sleep. Short sleep duration, defined here as getting six hours, has been linked to higher odds of being dehydrated. 

The fix: Drink more water, but avoid it in the hours before bed to minimize the risk of middle-of-the-night bathroom trips.

13. Alcohol 

You’ll feel tired in the morning when hungover, but alcohol affects your sleep and energy in more ways than that:

  • Alcohol fragments your sleep, meaning you wake up often during the night.
  • It changes your sleep architecture by suppressing REM sleep.
  • Binge drinking has been linked to insomnia.
  • Alcohol can cause you to snore and develop sleep apnea. 
  • A hangover can make you feel tired and affect your sleep days after drinking.
  • If you’ve become dependent on it, you might find you can’t sleep without alcohol.
  • If you have alcohol abuse problems, it can cause insomnia when drinking and when going through withdrawal. 

We’ve covered more on why you can’t sleep after drinking alcohol here.

The fix: Avoid alcohol at least three to four hours before bed. RISE can give you an exact time each day. Prioritize getting enough sleep after drinking to reduce how much it’ll affect your energy levels in the following days.

14. Lack of Exercise

The last thing on your mind when feeling tired is working out, but a lack of physical activity may be the cause of your sluggishness. 

Regular exercise can not only help manage your weight and stress levels, it can also help you fall asleep at night. 

On the flip side, too much exercise can make you feel tired. 

The fix: Get more movement into your day, but avoid intense exercise within an hour of bedtime as this can keep you up. RISE can tell you when to avoid a workout and when your energy levels will be at their highest each day, so you can schedule a gym session and make the most of this energy. 

RISE app screenshot showing you best time for healthy energy boost
RISE can tell you the best time to energy-boosting activities like working out.

15. Being Overweight, Underweight, or Losing Weight

Your weight — and whether you’re gaining it or losing it — can make you feel tired and like you have no energy. 

Being overweight means your body has to work harder, and obesity is a risk factor for snoring, sleep apnea, type 2 diabetes, and depression. Being underweight means you get tired more easily and you’ll feel drained and weak. 

During a weight loss journey, eating fewer calories and doing more exercise may make you feel tired. Taking weight loss drugs like Ozempic, Wegovy, or Zepbound may cause sudden crashing fatigue as side effects like nausea cause sleep loss and the large cut in calorie consumption adds to tiredness.

The fix: Make some healthy lifestyle changes to move towards a healthy weight. Prioritize keeping sleep debt low for more energy — this can also help you lose weight. Speak to a doctor to get help navigating weight loss medication side effects. 

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16. Thyroid Problems 

Thyroid problems can be a cause of fatigue, and these problems are more common in women

Your thyroid gland is responsible for producing hormones to regulate your metabolism.

Hypothyroidism, or underactive thyroid, when your thyroid doesn’t make enough hormones, can cause you to feel fatigued. It can also cause you to feel depressed and gain weight — both of which can impact your sleep. 

Hyperthyroidism, or overactive thyroid, when your thyroid makes too much hormone, can cause you to feel irritable, weak, fatigued, and have trouble sleeping. 

Essentially, if your thyroid isn’t on point, your energy levels won’t be either. 

The fix: Your healthcare provider can do a blood test to check for the correct levels of thyroid hormone and suggest the best treatments. 

17. Medical Conditions

You might feel tired all the time, even with enough sleep, because of a medical condition. 

Fatigue is a common symptom of conditions like: 

  • PCOS — which affects the ovaries. Excessive daytime sleepiness and sleep apnea are also more common in women with PCOS.   
  • Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS)
  • Iron deficiency anemia 
  • Postural orthostatic tachycardia syndrome (POTS)
  • Fibromyalgia 
  • Diabetes 
  • Heart disease
  • Celiac disease 
  • Multiple sclerosis 
  • Lupus

Many of these health conditions affect more women than men, including iron deficiency anemia, chronic fatigue syndrome, fibromyalgia, and lupus

The fix: Speak to a healthcare professional to see if there’s an underlying cause of your fatigue.

18. Side Effects from Medications

Medications that come with fatigue as a side effect include: 

  • Antidepressants
  • High blood pressure medications 
  • Antihistamines 
  • Radiotherapy and chemotherapy treatments 

Medication can affect men and women differently. For example, the US Food and Drug Administration made Ambien lower the recommended dose of zolpidem (a sleep aid) for women because they were more at risk of next-morning impairment and car accidents. 

It seems women eliminate zolpidem more slowly from their systems. So, it’s thought women may have different rates of absorption, metabolism, and excretion of other medications, too, and this could lead to different side effects, including fatigue. 

The fix: Speak with your doctor about switching up your medication or try a different birth control method. 

19. Sleep Aids 

Sleepiness from over-the-counter sleep aids can often last into the next morning — known as the hangover effect. This is one reason women can feel tired in the morning. 

You can also become dependent on sleep aids, meaning you find it hard to get the sleep you need without them, which results in sleep debt and low energy. 

This can happen with sleep aids that don’t cause physical dependence. You may develop a psychological dependence on sleep aids like melatonin, for example.

Some sleep aids can cause rebound insomnia, when your sleep is even worse after using them than it was before. 

As women are more likely to be affected by insomnia, they may also find themselves reaching for sleep aids in an attempt to get some shut-eye.

The fix: Speak to your healthcare provider about slowing tapering off sleep aids. We’ve shared more advice on how to sleep without sleeping pills here. 

We’ve covered more ways you can get more energy here, including quick fixes for when you need an energy boost stat and long-term changes to make a real difference to your fatigue.

Fight Female Fatigue with RISE 

Women can feel tired due to high sleep debt and being out of sync with their circadian rhythms. Hormone fluctuations during their periods, pregnancy, and menopause; taking hormonal contraceptives; and anxiety and depression can all cause fatigue, too. 

To get more energy as a woman — or a man — work on lowering your sleep debt and getting in sync with your circadian rhythm. One win-win? This will make sleep disruptions like period pain and menopause hot flashes easier to deal with. 

The RISE app can work out how much sleep debt you have and keep track of it as you pay it back. It can also predict your circadian rhythm each day, so you can easily sync up with it. 

And the app can guide you through 20+ good sleep hygiene habits to help you get the good night’s sleep you need for more energy. 

Female users say RISE helps them feel better: 

“I didn’t realize how bad my sleep debt was. I didn’t even realize how badly it was affecting me. I don’t wake up feeling sick and emotionally unstable every day anymore. RISE really helped me in just a couple weeks and I plan on continuing to use it so I stay on track.” Read the review.

It doesn’t take long to feel the difference — 80% of RISE users feel more energy within five days. 

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The power behind your next best day

RISE makes it easy to improve your sleep and daily energy to reach your potential

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