Fatigue, or lack of energy, is one of the most common symptoms associated with major depressive disorder (depression). Most people with depression report they feel tired or fatigued on an almost daily basis.
If you feel fatigued every day, and you don’t have another medical condition that could explain it, then it could be depression. Here are the reasons why depression is so frequently linked to fatigue, as well as how to cope if you’re experiencing fatigue from depression.
Why does depression cause fatigue?
There are several reasons that could explain why depression so often leads people to feel fatigued. Some are biological, and connected to the way depression affects your brain. Others are behavioral — meaning the way depression makes you act could be contributing to your tiredness.
The role of neurotransmitters
Depression affects the neurotransmitters  in your brain, like dopamine, serotonin, and norepinephrine. These neurotransmitters affect your energy, motivation, and sleep, among other things. When the levels of these chemicals aren’t where they’re supposed to be, it can cause you to be more fatigued than usual.
Lack of sleep
People with depression often feel tired because of a fairly obvious reason: they aren’t sleeping enough. One of the core symptoms of major depressive disorder (along with many other mental illnesses) is sleep disturbance. And it’s very common for people with depression to also live with insomnia. 
You may be feeling so tired during the day because you aren’t sleeping restfully enough at night. This could be because you’re lying awake at night with depressive thoughts. Many people with depression also deal with hypersomnia, which can cause excessive daytime sleepiness and too much time spent sleeping.
Sleep apnea may also be a factor. Studies show that depression is very common among people with sleep apnea.  Sleep apnea is a serious condition that severely interrupts sleep quality.
Sleep and depression have a bi-directional relationship, which means their connection goes both ways. Insomnia and hypersomnia are both common symptoms of depression. But a lack of sleep can also make depression worse.
Lack of exercise
People with depression may also find it difficult to gather the motivation to exercise. You may have had a thought like, “I’m already so tired. Why would I want to work out and make myself even more tired?”
But a lack of physical activity actually has a positive relationship with fatigue  — in other words, the less you exercise, the more tired you become. If people with depression are less likely to exercise, then it would follow they may also be more likely to be tired.
The reason why people with depression are less likely to exercise is complex. It’s often related to motivation — it’s hard to feel motivated to work out when you feel hopeless about everything. Fatigue and exercise can also get caught in a Catch-22. The less you exercise, the more tired you’re likely to feel. But the more tired you are, the less motivated you feel to exercise.
Medication side effects
People with depression often take medication, which could also contribute to fatigue. This includes antidepressants or other types of psychiatric medications to treat the depression itself. But medications for other health conditions that have a close relationship with depression could also play a factor.
Antidepressants, like selective serotonin reuptake inhibitors (SSRIs), list drowsiness as one of their main side effects.  You could be especially tired if you’ve only recently started taking medication. If you also take medication for anxiety, this could make you feel even more tired.
Diet and fatigue have a strong connection. People who eat a nutritious diet are more likely to have healthy energy levels throughout the day. Certain vitamin and mineral deficiencies , like iron or Vitamin D deficiency, could also lead to fatigue.
People with depression may be less motivated to eat a healthy diet, which could lead to fatigue. They may also lose their appetite, which can cause them to not get the caloric intake they need to maintain high energy levels.
Drug and alcohol use
People with depression are twice as likely  to have a drug or alcohol addiction than people without any mood problems. Many people with depression use drugs and alcohol to try to escape from their symptoms. This is called self-medication. In these cases, it could be the drugs that are causing tiredness, on top of the depression itself. For example, abusing benzodiazepines can cause extreme sleepiness.
Some people may also use substances like alcohol to try to fall asleep at night. Although alcohol could help them fall asleep initially, it actually disrupts the sleep-wake cycle over the long term. This could cause your sleep quality to be poor, which might lead to daytime fatigue. 
Stress and anxiety
Anxiety and depression are also deeply intertwined, and many people live with both conditions. Up to 70% of people with depression also have symptoms of anxiety. 
Living under stress and anxiety can be exhausting. You may constantly have worries racing through your mind, which could cause tension in your body and keep you awake at night.
Persistent low-grade inflammation in the body has been linked to several forms of fatigue in scientific research.  Inflammation can also have negative effects on the central nervous system, which could contribute to depression.  People who have an inflammatory immune system response, like allergies or asthma, also have higher rates of both depression and fatigue.
This could partially explain the biological link between depression and fatigue. Research has found that antidepressants work to decrease the inflammatory response in the body.
Other comorbid health conditions
Depression has a close relationship with many medical conditions. For example, people with cancer , MS , and migraines  all have a higher likelihood of being depressed than the general population.
All of these conditions could also cause fatigue. In other words, it could be the third factor (another health condition) that’s leading to both depression and fatigue.
Am I depressed, or just tired?
Fatigue is so common in today’s population that it can almost be described as a normal effect of adult life. Over 60% of American adults state that they feel tired at least some of the time .
So how can you tell whether your tiredness is caused by depression, or something else?
Only a doctor or a mental health therapist can tell you whether or not you meet the criteria for a depression diagnosis. They can also complete a full medical evaluation to rule out any other health condition that could be contributing to your fatigue. If you are experiencing tiredness that doesn’t go away, then talk to your medical provider about what could be going on.
When fatigue is caused by depression, people generally experience the other symptoms of depression as well.
On top of fatigue, the other main symptoms of depression are:
- Low, empty, or irritable mood almost all the time
- Loss of interest in activities you used to enjoy
- Feelings of hopelessness
- Feelings of worthlessness and guilt
- Difficulties with concentration and focus
- Sleep disturbances (insomnia or hypersomnia)
- Changes in appetite, which can cause weight loss or gain
- Unexplained aches and pains
- Recurrent thoughts of death or suicide
It’s best to talk to your medical provider about what the root of your fatigue could be. At The Center • A Place of HOPE, our admissions team also completes a full assessment to get a picture of your overall health.
How to cope with fatigue caused by depression
Luckily, there are lifestyle changes you can make that could help reduce the level of fatigue you feel because of depression. Here are just a few.
Get some sleep
One of the best things you can do to improve fatigue is to improve your sleep habits. Make sure you practice good sleep hygiene to maximize the chances of getting a good night’s sleep. When you sleep well, you may be more likely to have more energy when you wake up.
Physical exercise is a great way to both improve depression symptoms and increase your energy levels. In the research, exercise has been found to significantly lift mood. It can be difficult to find the motivation to exercise when you have depression, so start with small steps.
Eat nutrient-rich foods
Even if your depression causes you not to have an appetite (or eat “comfort foods” that may not be healthy), try to eat a diet that’s filled with vitamins and nutrients. In particular, eat foods like:
- Fruits and vegetables
- Fatty fish, like salmon
- Dark chocolate
- Grains and legumes
These may help you get your energy levels back. 
Lay off the alcohol
You might feel like alcohol and other drugs help with depression symptoms. But in reality, these substances keep you locked in a vicious cycle. Using alcohol and drugs to cope can worsen your sleep quality and make you feel even more tired. On top of that, these habits can put you at risk of developing substance use disorder, which can make depression worse.
Get mental health treatment
If you still feel fatigued after trying these strategies, it may be time to seek mental health treatment for depression. Mental health treatments like therapy and other holistic methods can target your depression directly. Licensed practitioners get to the root of your depression and help you learn coping skills to live a happier and more fulfilled life.
At The Center • A Place of HOPE, we use a whole-person approach to depression treatment, which means we won’t simply give you a pill to “fix” your anxiety problems. We’ll work together with you to find an individualized holistic treatment method that works for you. We understand that many different factors — physical, mental, emotional, and spiritual — can contribute to fatigue.
Get in touch with us to learn more about our admissions process and how you can start your treatment journey with us today.