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Why am I so tired?

If you are sleeping enough but you still feel tired during the day, there are various possible causes. We consider the common medical, psychological and lifestyle factors that lead to chronic tiredness.

If you’re getting enough sleep but still find yourself yawning through the day, you’re not alone. Studies suggest that one in five people feels unusually tired at any given time, and one in 10 experiences prolonged fatigue.1

There are many reasons why you might be feeling perpetually exhausted. The mot common causes can be broadly categorised under sleep problems, lifestyle factors, psychological causes, and medical conditions.

Sleep problems

The first thing to establish is whether you really are getting enough sleep. For most people, this means around eight hours of good quality sleep each night. Some people need more and some less, with the majority falling between seven and nine hours.

You may think you’re getting enough sleep, yet many people overestimate how much they’re actually getting, or underestimate how much they need.

It’s thought that around three quarters of British adults sleep less than seven hours a night.2

So, before you discount lack of sleep as the cause of your tiredness, make sure you really are getting enough.

Sleep disorders

Sleep disorders are another common cause of feeling tired all the time. Insomnia is the most common, affecting most people at some point in their lives, and around 10% of people chronically. Other conditions that can interfere with your sleep include obstructive sleep apnoea, restless leg syndrome and REM sleep behaviour disorder.

If you’re suffering from a sleep disorder, or think you might be, an assessment at a Sleep Clinic could help you to control the issue and feel less tired.

Lifestyle factors

There is unlikely to be one aspect of your lifestyle that is making you tired; usually there are various interlinked factors that conspire to make you sleepy. Some factors that might be at work include:

Alcohol and caffeine

Drinking coffee and tea during the day and/or alcohol during the evening can disrupt your night’s sleep and stop you getting good quality rest. If you are experiencing fatigue, try to limit your consumption of caffeine and alcohol and see if it helps.

Diet and nutrition

What you eat is closely linked to your energy levels. For example, eating sugary foods gives you a short-term boost but can make you crash later in the day, so try to stick to slow release energy sources such as fruit, vegetables and wholegrain carbohydrates. You will also feel tired if you crash diet, as you’re not taking in enough energy to fuel your body.

If you think your food choices could be to blame – even partly – try eating a healthy diet and see if it helps improve your energy levels.

Being underweight or overweight

If you are at an unhealthy weight for your size, your body has to work harder than normal to do everyday tasks. This means you’ll get tired more easily. You may find that achieving a healthy weight will help you to feel more alert and give you more energy.

A lot of factors affect your weight, and a lot of factors will affect what weight is healthy for you. Don’t be tempted to start a crash diet, but instead seek medical advice from a specialist, for example a dietician.

A sedentary lifestyle

It can be hard to be active if you feel tired all the time. When you’re exhausted, it’s difficult to motivate yourself to move and exercise, but this creates a vicious cycle. The less you move, the more tired you will feel, but your sleep quality may not be as good.

The good news is, even small changes can have a big impact. Taking a ten minute walk each day in the natural light and fresh air can help you to feel more awake in the day and sleep better at night.

Sedentary lifestyles tend to go hand-in-hand with lots of screen time. If you are someone who looks at screens late into the night, this may well be affecting your sleep. The artificial light they produce can suppress your production of sleep hormones. Try switching off at least an hour before you want to sleep.

Psychological causes

The most common reasons that people feel fatigued are psychological causes. The state of your mental wellbeing can have a huge impact on your ability to sleep well, as well as affecting other lifestyle factors such as eating well and exercising regularly.

Emotional events

Emotional shock can be extremely draining, and even positive events such as moving house or getting married can be exhausting.
If you have experienced bereavement or a relationship break-up, it is common to feel a lack of energy as you process the changes to your life. If you think talking could help, counselling can be a good option.


If you are having a stressful time or are worrying a lot, your sleep is one of the first things to be affected. Pressure at work and financial worries are among the most common factors that keep people up at night.

Stress can make it more difficult to sleep, and in turn lack of sleep can exacerbate feelings of stress. If you think stress could be a factor in your fatigue, counselling or other therapy may benefit you.

Anxiety, depression and other mental health issues

Mental health issues have a profound affect on our sleep, and often go hand in hand with feeling tired all the time. Both fatigue and sleep disturbances are highly prevalent among people with mental health disorders. This is true of anxiety, depression and many other conditions.
If you suffer with mental health problems and are experiencing excessive tiredness, talk to your doctor, who will be able to advise you on how to address the issue.

As well as stopping you from sleeping, mental health problems can manifest in a feeling of listlessness and fatigue. Depression and anxiety can make you feel physically unable to take part in everyday activities.

Medical conditions

As well as mental health issues and illnesses, there are a number of physical conditions that can cause tiredness. Most of these will elicit other symptoms alongside fatigue.

If the onset of your excessive tiredness coincides with any other unexplained issues such as weight loss, extreme thirst, hair loss, heavy periods, or a change in bowel habits, it may be that your tiredness has an underlying physical cause. If you do see any of these symptoms, it’s important to speak to your GP.

Your doctor will likely organise blood tests to check for common tiredness-inducing conditions such as anaemia (iron deficiency). They may also check for conditions including diabetes and heart disease, food intolerances and other allergies, and obstructive sleep apnoea.

A condition called chronic fatigue syndrome (also called ME, and often referred to as CFS/ME) is another potential cause. This is a severe illness that can make you feel physically exhausted. It tends to last for at least six months. The tiredness is often accompanied by symptoms such as muscle pain, joint pain, and headaches.

Excessive tiredness can be a symptom of so many underlying causes, both mild and severe. If you can’t put your fatigue down to lack of sleep, lifestyle factors or any medical issue – physical or mental – you should speak to your GP so that they can help you rule out anything serious.


1Royal College of Psychiatrists
2Sleep Council
3American Academy of sleep Medicine