There are tons of self-help books and guides to getting more out of your day. Often times, this includes cutting back on your sleep. “You can sleep when you’re dead,” some might say. But this attitude can be very harmful to your health.

The average adult still needs somewhere between 7 and 8 hours a night. Although, some people can function properly with as little as 6 hours and others might need as much as 9 hours. How much sleep you need is determined by your genes and often varies from person to person. This means that only you know how much sleep you need. The key to determining how much sleep you need is in how you’re feeling the next day. You want to feel awake and rested without the help of caffeine. If you only sleep for five hours without feeling tired or drowsy the next day, then you’re probably getting enough.

But why do we need sleep at all? Sleep is an essential function that works partially to restore your body. Without deep sleep, you lose cognitive function like memory recall, your concentration will plummet and you’ll react much slower to the world around you. This is why driving a car while sleep deprived is just as dangerous as driving drunk.

Some self help books and articles will tell you that you can power through it. As long as you go to bed thinking you’ll wake up rested, you will no matter how much sleep you get. While there is something to going to bed relaxed, there’s no way to think yourself out of being sleep deprived. Caffeine is only putting a bandaid on the larger problem. If you can’t function properly throughout the day without a few cups of coffee, then you are probably not getting enough sleep.

The problem is only compounded by multiple days without enough sleep. You can probably reasonably make it through one day with less sleep than usual, but you better make up for it. But if you go through an entire week with little sleep, you’re opening yourself up for more health problems. Studies have shown that insufficient sleep is linked to heart disease, heart attacks, diabetes and obesity. Another study also demonstrated that sleep deprivation can lead to lower immunity, leaving you open to contracting bacteria and virus infections like the common cold.

Sleep is a necessary bodily function that you need in order to live a full, happy and healthy life. There is no way to get around it. So instead of trying to avoid sleep, embrace it.