Recent Blog Articles
When — and how — should you be screened for colon cancer?
Got expendable body parts?
How to help your child get the sleep they need
What color is your tongue? What's healthy, what's not?
Immune boosts or busts? From IV drips and detoxes to superfoods
The new RSV shot for babies: What parents need to know
Dealing with thick, discolored toenails
Prostate cancer: A new type of radiation treatment limits risk of side effects
Harvard Health Ad Watch: Why are toilets everywhere in this drug ad?
Will miscarriage care remain available?
Why am I so tired?
Weariness, fatigue, low energy, exhaustion. There are many ways to describe those times when you feel so tired you can’t do anything. To be clear, fatigue is more than simply feeling sleepy: it includes components that are physical (weariness or weakness), mental (lack of concentration and sharpness), and emotional (lack of motivation or boredom).
Some causes of fatigue may be apparent, like having a cold or flu (or even COVID-19), overworking, not eating well, stress, or having a sedentary lifestyle. Others are harder to pinpoint and may be caused by medical conditions, age, or life changes. If you feel tired all the time for no clear reason, you should consult your doctor to check for any of the following issues.
Anemia. This occurs when your blood has too few red blood cells, or those cells have too little hemoglobin, a protein that transports oxygen through the bloodstream. The result is a drop in energy levels.
Heart disease. Heart disease can cause the heart to pump blood less efficiently and lead to fluid in the lungs. This can cause shortness of breath and reduce the oxygen supply to the heart and lungs, making you tired.
Hypothyroidism. An underactive thyroid gland can cause fatigue and other symptoms, such as weight gain, weakness, dry skin, feeling cold, and constipation.
Sleep disorders. Sleep disruptions will leave you feeling tired the next day. Two of the most common are insomnia and sleep apnea. With insomnia, you may have trouble falling asleep, staying asleep, or getting good-quality sleep. Sleep apnea is characterized by pauses in your breathing, often lasting several seconds, or shallow breathing, while you sleep. Other issues can disrupt sleep, such as restless leg syndrome and conditions that force repeated nighttime bathroom trips such as an overactive bladder or enlarged prostate.
Medication. Some medications can make you feel tired, such as certain blood pressure drugs, antidepressants, anti-anxiety drugs, and antihistamines.
Hormonal changes. Fatigue is a common symptom of low hormone levels like testosterone in older men and estrogen in women during menopause.
Low-grade depression or anxiety. Mental health issues like depression or anxiety often cause low energy.
Chronic fatigue syndrome. Severe prolonged tiredness could be a sign of chronic fatigue syndrome, a mysterious disorder characterized by profound fatigue that does not improve with rest and may worsen with physical or mental activity.
Types of fatigue
Ask any three people what fatigue feels like, and you’ll likely get three different answers. That’s because the experience that people call “fatigue” may refer to different feelings—for example, physical fatigue that causes lack of strength and endurance, mental fatigue that leads to slow reaction times or poor concentration, and emotional fatigue that leaves your spirits deflated.
The experience of fatigue is often classified as one of two general types: muscle fatigue and central (or brain) fatigue. Muscle fatigue and central fatigue are closely related. When you feel fatigued, you’re usually feeling the effects of both types. But you can also experience one without the other.
Muscle fatigue is the weakness that comes when you’ve tired out your muscles, like after exercise or activity. When muscles become fatigued, they don’t contract as forcefully or as quickly as muscles that are rested.
Central (brain) fatigue
When most people say they are fatigued or lack energy, they are describing a condition called central fatigue or brain fatigue. They mean that they are having trouble paying attention, concentrating, or feeling motivated to perform. They may also feel sleepy. Specific areas of the brain are responsible for attention and concentration, and other areas are centrally involved in motivation. Still others are involved in alertness and sleepiness.
Emotional and psychological factors significantly affect how fatigued you feel. For example, fatigue is greater and comes on sooner in people with mood disorders such as depression or anxiety than in those who don’t have these illnesses.
Fatigue caused by a medical or mental health condition needs proper attention from your primary care provider.
Here are ways you can treat and manage everyday fatigue:
Exercise. Regular physical activity almost guarantees that you’ll sleep more soundly. It also gives your cells more energy to burn and circulates oxygen through your body. And exercising can lead to higher brain dopamine levels, which helps elevate mood. Try to avoid exercising within two hours of bedtime, which can make it harder for you to fall asleep.
Eat for energy. A diet that contains foods with a low glycemic index—whose sugars are absorbed slowly—may help you avoid the lag in energy that typically occurs after eating simple carbohydrates or refined starches. Foods with a low glycemic index include whole grains, high-fiber vegetables, nuts, and healthy oils like olive oil. High-carbohydrate foods have the highest glycemic indexes whereas proteins and fats have a glycemic index close to zero.
Use caffeine wisely. Caffeine does help increase alertness, so having a cup of coffee can help sharpen your mind. But to get the energizing effects of caffeine, you have to use it judiciously. It can cause insomnia, especially when consumed in large amounts or after 2 p.m.
Limit alcohol. One of the best hedges against the midafternoon slump is to avoid drinking alcohol at lunch. The sedative effect of alcohol is powerful at midday. Similarly, avoid a five o’clock cocktail if you need energy in the evening. If you’re going to drink, do so in moderation at a time when you don’t mind having your energy wind down.
Stay hydrated. If your body is dehydrated, one of the first signs is fatigue. Drink water throughout the day. Although individual needs vary, the Institute of Medicine recommends men should aim for about 15 cups of fluids per day, and women about 12 cups. Besides water and beverages like coffee, tea, and juices, you can also get your fluids from liquid-heavy fruits and vegetables that are up to 90% water, such as cucumbers, zucchini, squash, strawberries, citrus fruit, and melons.
Restrict your sleep. If you think your fatigue is related to being sleep-deprived, try getting less sleep. This advice may sound odd, but determining how much sleep you need can reduce the time you spend in bed not sleeping. This process makes it easier to fall asleep and promotes more restful sleep in the long run. Here’s how to do it:
- Avoid napping during the day.
- The first night, go to bed later than usual and get just four hours of sleep.
- If you feel you slept well during those four hours, add another 15 to 30 minutes of sleep the next night. As long as you’re sleeping soundly the entire time you’re in bed, slowly keep adding sleep on successive nights.
Lighten your load. One of the main reasons for fatigue is overwork. This can include professional, family, and social obligations. Try to streamline your list of “must-do” activities. Set your priorities regarding the most critical tasks, and pare down those that are less important. Consider asking for extra help if necessary.
Control stress. Stress-induced emotions consume massive amounts of energy. Talking with a friend or relative, joining a support group, or seeing a psychotherapist can all help diffuse the stress response. Relaxation therapies like meditation, yoga, and tai chi are also effective tools for reducing stress.
Do you sometimes feel like the Energizer Bunny when his battery runs low? You might start the day strong, but by mid-afternoon, you can't quite keep going and going. Assuming your doctor has ruled out serious medical causes, there are many ways to boost energy levels. For example:
Caffeine. Caffeine increases alertness, so having one or two cups of coffee can help sharpen your mind. But be careful. Too much caffeine, especially when consumed in large amounts or after 2 p.m., can disrupt your sleep and lead to energy loss. Energy drinks are popular energy boosters, but high amounts of caffeine give them their celebrated jolt. Many contain as much or more caffeine as a cup of coffee, along with loads of sugar and other additives, so you should be careful how and when you consume them.
Diet. Given that food is fuel, it's only natural to wonder if certain foods boost energy more efficiently than others. It is important to eat a healthy balanced diet that includes plenty of fruits and vegetables, whole grains, and healthful sources of fat and protein, however, there is little scientific evidence regarding the effects of specific foods on a person's energy level.
Sugar is a simple carbohydrate quickly digested and absorbed into the blood. Consuming foods high in sugar, like candy bars or similar sugary snacks, can make you more alert and energized, but it’s temporary, lasting only about 30 minutes. Afterward, you may actually feel less energetic than you did before, the so-called sugar crash.
Unless you have a diagnosed vitamin deficiency that can increase fatigue, like iron, vitamin D, or vitamin B-6 or B-12, you don't need to take supplements. Also, avoid over-the-counter multivitamins, formulas, and herbal remedies promoted as “energy boosting” as there is no evidence they have any such effect.
Exercise. Exercise can boost energy levels by raising energy-promoting neurotransmitters in the brain, such as dopamine, norepinephrine, and serotonin, which is why you feel so good after a workout. It doesn't matter what kind of exercise you do, but consistency is key. Some research has suggested that as little as 20 minutes of low-to-moderate aerobic activity, three days a week, can help sedentary people feel more energized. For a quick energy boost, take a brisk walk around the block or do a series of push-ups, lunges, or squats—anything to get your body moving.
Drink water. Fatigue is an early sign of dehydration, so drink a glass of water whenever you begin to feel run down.
Take a nap. A 20- to 30-minute early afternoon power nap can rejuvenate both body and mind. But don't nap too late in the day or for too long as it can interfere with your nighttime sleep.
Free Healthbeat Signup
Get the latest in health news delivered to your inbox!