7 Reasons Why You’re Tired After 8 Hours of Sleep (And What To Do)

An image of someone tired after 8 hours of sleep

We all know that we should be getting enough sleep each night to improve our health and keep us happy and productive.

But sometimes, even if when we think we’ve managed it, we can still be tired after 8 hours of sleep.

This can be frustrating and confusing.

So let’s take a deeper look into why this might be happening and what you can do about it.

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Why Is Getting Enough Sleep Important?

The recommended amount of sleep each night for adults is between 7 and 9 hours.

While some of the reasons we need to sleep are still a mystery, we know a lot about the effects of sleep deprivation on our physical and mental health.

Short-term effects of sleep disruption

  • Increased stress
  • Somatic pain
  • Reduced quality of life
  • Emotional distress
  • Mood disorders
  • Problems with cognition, memory, and performance

Long-term effects of sleep disruption

  • Hypertension
  • High cholesterol
  • Cardiovascular disease
  • weight issues
  • Metabolic syndrome
  • Type 2 diabetes
  • Colorectal cancer
  • Increased risk of death from all causes

And, aside from all of these severe health impacts, the fact is that if you don’t get enough sleep, you will feel tired.

This can make getting through the tasks you need to get done much more of a struggle.

Why Do I Feel Tired After 8 Hours of Sleep?

If you feel tired, even after a full night’s sleep, you don’t have to live with it.

There are many reasons why this could be happening, and there are actions you can take to try and fix the problem.

1) Inaccurate sleep tracking

It can be pretty tricky for us to estimate how much sleep we get each night accurately.

This is partly because we can never be precisely sure of the precise time that we fell asleep.

We can easily overestimate how much sleep we have had.

So you may think that you have 8 hours of sleep when, in fact, you have had less than the recommended amount of rest after all.

How can you track your sleep?

There are plenty of options for sleep trackers that can help you track your sleep accurately.

These can range from watch-style activity trackers on your wrist to electronic pads that you place under your body.

These trackers use heart rate and body movements to record how much of the night you spent asleep.

And they can also tell you how deeply you slept.

If you’re not sure whether you are sleeping for the whole 8 hours, then this can be an excellent option for you to find out for sure.

If you aren’t, you can then take steps to improve your sleep health to sleep for longer.

2) Alcohol

If you’re feeling tired even after a whole night’s sleep, one of the reasons for this could be because you’d had a drink the night before.

It can feel as though having an alcoholic drink sends us quickly into a deep slumber, but the opposite is true.[1]

Alcohol makes:

  • Us take longer to get to sleep
  • The first half of sleep shorter
  • The second half of our sleep more disrupted

This means that our sleep quality is a lot poorer after we’ve had an alcoholic drink.

So, in reality, while you might have been in bed for 8 hours, you got much less than 8 hours of sleep in total.

3) Sleep apnea

For people with sleep apnea, their breathing stops and starts throughout the night.

The most common type of sleep apnea, obstructive sleep apnea, happens because your airways become too narrow when you are asleep.

Some people are more at risk of developing sleep apnea than others, including:

  • Obese people
  • People who have large necks
  • Those who have a family history of sleep apnea
  • People who smoke or drink alcohol
  • Back sleepers

One of the most common symptoms of sleep apnea is daytime sleepiness.[2]

When you stop breathing during the night, your body wakes you up, even if it’s briefly.

So you end up having much less sleep than you usually would.

How to treat sleep apnea?

If you suspect you may have sleep apnea, your doctor can help you.

There is a range of treatment options, including lifestyle changes and the use of sleep breathing aids such as a CPAP machine, that can help you have a more rested night’s sleep.

If along with sleepiness after being asleep for 8 hours, you also have the following symptoms, it could be worth finding out if you have sleep apnea:

  • Your breathing stops for short periods through the night (and you probably not aware of it).
  • You make gasping, snorting, or choking sounds in your sleep (again, you may need someone else to point this out).
  • You wake up during the night.
  • Snooting (you may not notice this yourself either).
  • Lack of concentration during the day.
  • You have mood swings.
  • Waking up with a headache.

If you do have sleep apnea, it is essential to get treatment as soon as possible as it can cause some severe health problems if it is left untreated.

4) Heavy exercise late in the day

The relationship between exercise and sleep is complicated.

It is well established that regular exercise is an essential component of good sleep health and can help you have a deeper and more restful sleep.[3]

But there are some situations where exercise can interrupt your sleep.

If you take part in heavy exercise late at night or you overtrain, this can make your sleep quality worse.[4]

It makes your sleep more disrupted and prevents you from moving through the different sleep phases the way that you should get a restful night.

So if you’re still tired after a whole night’s sleep, it could be because you exercised too late at night or have been training too hard.

How to handle sleep disruption due to late exercise?

To avoid exercise interfering with your sleep, you should try to exercise in the afternoon rather than the evening and see if that helps.

It can give your body time to settle back down to its normal rhythm before it is time for you to go to bed.

If you want to exercise in the evening, you should try something non-aerobic, such as yoga or pilates.

5) Narcolepsy

Narcolepsy is a relatively rare condition, but it can cause you to feel tired even after a whole night’s sleep. There are four primary symptoms of narcolepsy:[5]

  • Excessive daytime sleepiness
  • Cataplexy (sudden muscle weakness, often triggered by strong emotions)
  • Hypnogogic hallucinations (these are the dreams that you have when you are awake but falling asleep)
  • Sleep paralysis (when you wake up during REM sleep so cannot move)

The exact cause of narcolepsy isn’t known, but it can be triggered by hormonal changes, a major psychological stress event, or an infection.

What you can do

If you suspect you may have narcolepsy, you should go and see your doctor.

Thankfully, narcolepsy doesn’t cause any severe health problems, but it can have a significant impact on your ability to function and your emotional wellbeing.

There is no cure for narcolepsy, but some treatments can help manage the condition.

These include:

  • Lifestyle changes that can help improve your sleep habits
  • Medicine that can limit the condition’s impact on your daily life
  • Taking short naps evenly spaced during the day

6) Caffeine

Caffeine is the most widely used stimulant in the world.

More than 90% of Americans consume caffeine in some form every single day of their lives.[6]

We know that caffeine can positively impact our performance, cognition, and alertness, but its negative effect on sleep can sometimes be forgotten.

Of course, if you consume caffeine right before you go to bed, you can expect to have difficulty falling asleep.

So many of us limit our caffeine use to earlier in the day.

But what many people don’t realize is that caffeine can also affect the quality of our sleep.

While the levels of caffeine in our system get lower a few hours after consuming it, there can often still be enough in our system to disrupt our sleep.

If you drink coffee later in the day, even within 6 hours before going to bed, you may find that you are tired when you wake up.

Another complication with caffeine is the effect of withdrawal.

Many of us are reliant on caffeine and have developed a tolerance for it.

During the night, we go through a period of caffeine withdrawal.

The symptoms of caffeine withdrawal can include:[7]

  • headache
  • fatigue
  • irritability
  • decreased energy
  • depressed mood
  • difficulty concentrating
  • feeling foggy-headed
  • lack of contentment

If you are a regular caffeine consumer and wake up tired after 8 hours of sleep, you may be dealing with caffeine withdrawal.

Whow to handle disruption of sleep due to caffeine?

It can be almost impossible to eliminate caffeine from our diets altogether.

It is in coffee, tea, energy drinks, chocolate, and even over-the-counter medications such as cold remedies.

However, some people do successfully manage to become caffeine-free, so this could be an avenue to explore.

If you can’t or don’t want to give up caffeine entirely (and many of us don’t!), there are some steps you can take to help reduce its effect on your sleep.

The recommended daily allowance of caffeine is no more than 400mg a day.

This is the equivalent of four cups of coffee, 10 cans of coke, or two energy drinks.

Most people consume around 280mg a day.[8]

Keeping within the safe levels of caffeine intake can help to reduce its potential negative effects.

Making sure that you don’t drink caffeine near bedtime can also help.

Remember that even caffeine consumed within 6 hours of going to bed can affect your sleep, so consuming caffeine only in the morning or early afternoon can help to mitigate its effects.

Regarding the effects of caffeine withdrawal making you tired in the morning, there is only one solution to that if you don’t want to give up caffeine entirely, and that’s to have some as soon as possible after you wake up.

You should see an immediate effect on your alertness and cognitive abilities after your first cup of coffee, and then you will be ready to face the day.

7) Restless leg syndrome

Restless leg syndrome affects between 7% and 10% of the U.S. population, and it can harm your sleep quality.[9]

We don’t know the exact cause of restless leg syndrome, but it seems to have a genetic component and may result from low levels of iron and/or dopamine in the brain.

Symptoms of restless leg syndrome include:

  • Unpleasant sensations in the legs and an irresistible urge to move them (it can feel like aching, pulling, crawling, and creeping in the legs).
  • Moving the legs reduce the sensations.

These symptoms are most likely to occur when you are at rest, including lying in bed, and if they are severe, they can wake you up throughout the night.

So even if you have been in bed for 8 hours, your sleep will have been disrupted, and you will wake up feeling tired.

How to handle disruption of sleep due to restless leg syndrome?

If you suspect you may have restless leg syndrome, you should seek advice from your doctor. A range of treatments can be offered to you, although it may take some trial and error to find the combination that works for you.

Common treatments include:

  • iron supplements
  • lifestyle changes (e.g. giving up tobacco, taking a warm bath, an exercise program, or special sleep aids for your legs)
  • anti-seizure drugs
  • dopaminergic drugs
  • opioids
  • benzodiazepines (usually used as a last resort because of their side effects)

The Bottom Line

If you are feeling tired after 8 hours of sleep, there are a few different potential causes.

Identifying which one could be causing the issue can help you to make the changes you need to feel more awake when you get up in the morning.

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