On average, adults need somewhere around 8 hours of sleep a night to feel their best throughout the day and in the long term. Unfortunately, good sleep is not simply a numbers game — many other factors come into play, factors that may explain why so many of us wake up tired even after sleeping an adequate number of hours. So how does this happen, exactly? We walk you through some of the reasons you don’t feel rested after waking up and what you can do about it.

Sleep Quantity vs. Quality

The first thing you need to know when it comes to sleep is that quantity doesn’t equal quality. You can sleep 8 hours and still not feel as rested as you’d want. Not only does the quality of our sleep interact with the quantity, but one study of college students also found that it can be more important in determining our overall well-being. According to the researchers, “[i]n subjects sleeping an average of 7 hours a night, average sleep quality was better related to health, affect balance, satisfaction with life, and feelings of tension, depression, anger, fatigue, and confusion than average sleep quantity.” That means that if you don’t feel rested, it’s just as important (if not more) to take steps to improve the quality of your sleep rather than just getting your hours in.

Reasons You’re Waking up Tired (and How to Deal)

1. You don’t have a sleep routine

Body clocks are very real, although they’re more scientifically known as circadian rhythms. These cycles designate the way humans’ internal cues interact with the world around them over a 24-hour period. Circadian rhythms are largely responsible for determining when we feel sleepy, when we feel alert and when we feel hungry, for instance. If you’re not sleeping and waking at the same time every day, your body clock will get confused as to when you need to feel sleepy, and this could disturb your sleep quality. To counter this, calculate what time you need to go to bed in order to wake up for work, the school run or whatever else you’ve got going on, and still get around 8 hours of shut-eye. Try to stick to the same time every day, even on weekends if you can. Avoid napping as well. Soon your body will learn when “bedtime” is, and when you need to feel alert. Taking CBD daily may also help support your sleep-wake cycle.

2. Your sleep conditions aren’t ideal

So you’re getting your 8 hours and sleeping at the same time most days, but you’re still waking up tired. Your sleep quality could be affected by how comfortable your sleeping conditions are. Sleeping on the right kind of mattress is crucial, especially if you’re waking up with aches in your neck, shoulders and back. If you suspect yours might be to blame for your poor sleep, it might be time to go shopping for a new one. You should also sleep in as dark a bedroom as possible, set the temperature so that you’re not too hot or too cold, and minimize any background noise whenever you can.

3. You don’t limit your screen time

If you consistently use your phone or tablet before bed, you’re not alone. Unfortunately, this habit that so many of us have picked up in recent years could be interfering with your sleep in a big way. There are two main reasons for this: One is that screens emit blue light, the same type of light emitted by the sun during the daytime. When we are exposed to blue light after sunset, it messes with our circadian rhythms and makes it more difficult to sleep, or to sleep well. Another reason is that the content we consume on our electronic devices is often very stimulating, or even sometimes distressing, which can keep us awake. A study in PLOS ONE found that “[r]estricting mobile phone use close to bedtime reduced sleep latency and pre-sleep arousal and increased sleep duration and working memory.” If you can, avoid screens 1 to 2 hours before bedtime to promote quality sleep.

4. You drink caffeine or alcohol too close to bedtime

Many lifestyle habits contribute to the quality of our sleep. For one, your beverages of choice could be interfering with your pursuit of restful sleep. Relying on a certain amount of caffeine throughout the day — and especially if you’re consuming it in the evening — could negatively impact your sleep. One review found that, in participants for various studies, “caffeine typically prolonged sleep latency, reduced total sleep time and sleep efficiency, and worsened perceived sleep quality. Slow-wave sleep and electroencephalographic (EEG) slow-wave activity were typically reduced, whereas stage-1, wakefulness, and arousals were increased.” Try to decrease your use of caffeine, especially in the evenings, and see if that improves your sleep quality. Also note that alcohol can significantly decrease your sleep quality, so try to limit your consumption wherever possible.

5. You’re experiencing sleep inertia

Sometimes, the reason you feel so groggy when waking up is simple: It’s called sleep inertia (a period of impaired performance and grogginess experienced after waking), and is very common. It usually lasts between 15 and 60 minutes, though it can last for hours after you wake up. Following all the steps above can help prevent the experience of sleep inertia. Drinking coffee in the morning, as opposed to later on in the day, may help you feel more alert.

6. You have a sleep disorder

Though lifestyle changes are often all it takes to improve your sleep quality, you may also be waking up tired because there’s something else going on. You could be experiencing a number of sleep disorders, including sleep apnea, which can lead to snoring and dry mouth in the morning, or insomnia, where you find it consistently difficult to sleep well. If your sleep problems persist and you suspect you may have an underlying condition, make sure to consult a physician, who can help you get to the bottom of it.

The Bottom Line

Waking up tired can feel extremely frustrating. You got your hours in, so what gives? Ultimately, it all comes down to giving your sleep hygiene the same amount of importance you would every other aspect of your health — from working out to following a skincare routine — because, yes, it is that important.

Iris Goldsztajn is a London-based writer and editor with seven years of experience creating content for various outlets. Her work has appeared in the likes of InStyle, Stylist and Cosmopolitan, and she won first place in Writing Magazine’s Grand Prize for a short story in 2020.