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Why Am I Tired After 8 Hours of Sleep – The Impact of Sleep Efficiency

You’re probably aware that most adults need about 7 to 9 hours of sleep each night to feel fully rested. However, you may still feel exhausted when you wake up in the morning, despite sticking to this recommendation. This could come down to your sleep efficiency.

And this can lead to many worrying questions: “The usual morning grogginess and tiredness aside, why am I tired after 8 hours of sleep? Do I have an underlying sleep disorder? Am I coming down with some chronic illness?”

There’s really no need to panic, even if you have a sleep disorder.

Besides, feeling tired after eight solid hours of sleep at night could be due to reasons that aren’t related to medical conditions.

This article looks at the common non-medical and possible medical reasons for feeling woozy after a full night’s sleep. We also share a few tips to help improve your sleep efficiency.

First, let’s briefly explain what sleep efficiency means.

Sleep Efficiency: How It Impacts Sleep Quality

Feeling out of whack in the morning usually shows low sleep efficiency. And by sleep efficiency, we mean the ratio of the actual time spent sleeping compared to the time spent in bed at night.

You have high sleep efficiency (85% or more) if most of your time in bed is spent actually sleeping. For example, if you sleep for 7 out of 8 hours in bed, your sleep efficiency is 87.5% (7 divided by 8 multiplied by 100).

On the flip side, if you spend 8 hours in bed but only get 5 hours of sleep, your sleep efficiency is about 62%, which is considered low.

An efficient sleep results in feeling energetic and well-rested in the morning because you have higher sleep quality with fewer interruptions.

Conversely, inefficient sleep may cause restlessness, tiredness, and mood swings. In more serious cases, long-term sleep deprivation can lead to severe health problems like high blood pressure, stroke, diabetes, and heart failure.

Now that we better understand sleep efficiency and how it impacts sleep quality, let’s consider the possible reasons for feeling tired and restless even after eight hours of sleep.

Why Am I Tired After 8 Hours of Sleep: Non-Medical Reasons

8 Hours Is Not Enough to Meet Your Sleep Need

Eight hours of sleep may work for most adults, but it may not be enough time to meet your sleep needs.

A 2016 study found that most healthy adults have an average sleep need ranging from 8 hours and 10 minutes to 8 hours and 54 minutes.

In other words, your sleep need may be closer to 9 hours if you feel groggy upon waking up.

You Slept Too Much

Another possible reason you feel sluggish in the morning is oversleeping.

Sleeping in may seem appealing, especially during weekends, but you risk upsetting your body’s rhythm if you deviate from your normal sleep pattern.

Sleeping more than your body needs can actually deplete your energy, leading to daytime fatigue.

You Are in Sleep Debt

Sometimes, demanding work schedules or some other unavoidable reasons can force you to miss a few hours of sleep some nights. If that’s the case, you are carrying sleep debt from previous nights, and sleeping eight hours for one night alone is not enough to clear the debt.

For example, if you have an 8-hour sleep need, but you only get 6 hours of sleep for five days, you build a sleep debt of 10 hours. In this case, you’ll find it increasingly difficult to feel fully rested each morning, and before long, you will start to have emotional, cognitive, and physiological problems.

You Have Poor Sleep Hygiene

Perhaps poor sleep hygiene is the most common reason for feeling tired after eight straight hours of shuteye at night.

Unfortunately, many people are unaware that certain daytime habits can affect nighttime sleep. For example, drinking coffee after 3 pm can make it difficult to fall asleep at night.

Drinking alcohol may make you doze off as soon as you hit the bed, but one of its downsides is waking you up in the middle of the night (in some cases, several times). This type of sleep interruption affects your energy levels upon waking up.

Other seemingly harmless habits that may affect sleep quality include vigorous exercise right before bedtime, eating a large amount of food before hitting the sack, napping for too long during the day, and not sticking to a regular sleeping time.

All these can cause low sleep efficiency even if you spend 8 hours in bed every night.

Why Am I Tired After 8 Hours of Sleep: Possible Medical Reasons

man in a robe yawning

You might be dealing with a sleep disorder if you maintain good sleep hygiene but don’t feel well-rested after eight hours of sleep.

Insomnia is a common sleep disorder that can affect sleep efficiency. You’ll have a hard time falling asleep if you have insomnia, and when you eventually drift off to sleep, you find it hard to get back to sleep if you wake up in the middle of the night.

It’s not hard to see why you will feel tired or even grumpy in the morning if you have insomnia.

If you struggle with insomnia, consider using sleep crystals. This simple but effective natural method will help you sleep better, improving your sleep efficiency.

Other sleep disorders that can make you feel exhausted after a full night’s sleep are:

  • Obstructive sleep apnea: A sleep-related breathing disorder that momentarily blocks the airways, causing you to repeatedly stop and start breathing while sleeping. This jolts you awake several times in the night.
  • Narcolepsy: Feeling extremely sleepy during the day due to the brain’s ability to control your sleep cycle.
  • Restless leg syndrome: An overwhelming need to keep your legs moving, leading to diminished sleep quality and daytime exhaustion.

How to Improve Your Sleep Efficiency

woman resting peacefully in bed

It may sound counterintuitive, but you don’t want to spend extra time in bed if you’re looking to achieve good sleep efficiency.

If you feel tiredness after eight hours of sleep, consider tweaking your sleep habits with the following tips.

  • Create a sleep schedule around your sleep need: This could mean going to bed earlier to catch up to 9 hours of sleep if 8 hours doesn’t meet your sleep need.
  • Create a sleep-friendly bedroom: Remove distractions like TV and computers from your sleeping environment. Do your best to reduce light and noise and make your bedroom temperature comfortable for more quality sleep.
  • Wind down before sleeping: Follow a relaxing bedtime routine, such as taking a hot or cold shower (depending on your preference) and listening to sleeping music to prepare your brain for downtime.
  • Do something relaxing if you can’t sleep: Don’t stay in bed if you can’t fall asleep after 20 minutes. Get up and reset by doing meditation or reading something not very mind-engaging.

Bottom Line

A sleep disorder or an underlying health issue or problems could answer “Why am I tired after 8 hours of sleep?”

That said, feeling exhausted and having high levels of fatigue in the morning might be due to poor sleep habits or insufficient shuteye time to meet your sleep need.

The good news is that you can improve your sleep schedule and efficiency with a few sleep-related lifestyle tweaks. For an in-depth understanding of more restful sleep, take a look at our detailed guide on the topic.