If you have to decide between sleeping for a couple of hours or just staying up, you should opt to sleep. Keep reading to learn why.

Sleep pressure is a feeling of tiredness that gets stronger the longer you stay awake. If you don’t sleep, your drowsiness will continue to get worse until you can finally get some rest.

Sleeping for 1 to 2 hours can decrease sleep pressure and make you feel less tired in the morning than you otherwise would by staying up all night.

If you don’t get enough sleep, you’ll likely experience:

While you’re asleep, your body cycles through four stages of sleep roughly every 90 minutes. On a normal night, you get 4 to 6 of these cycles.

Sleeping for a couple of hours or fewer isn’t ideal, but it can still provide your body with one sleep cycle.

Ideally, you should aim for at least 90 minutes of sleep so that your body has time to go through a full cycle. Research has found that sleeping for 90 to 110 minutes may help reduce grogginess when you wake compared to shorter 60-minute sleeping sessions.

The four sleep stages can be divided into two categories: rapid eye movement (REM) and non-rapid eye movement (NREM). NREM makes up about 75 to 80 percent of your sleep.

  • Stage 1 (NREM). Stage 1, called N1, is the lightest stage of sleep and lasts for about 1 to 5 minutes. Your brainwaves, breathing, and heart rate all begin to slow, and your muscles relax.
  • Stage 2 (NREM). In stage 2, which is called N2, your body temperature drops while your heart rate and breathing continue to slow. Stage 2 lasts for about 25 minutes in your first sleep cycle and gets longer with each additional cycle.
  • Stage 3 (NREM). Stage 3, also called N3 or deep sleep, is when your body repairs itself and strengthens your immune system. Even loud noises may not wake you from this stage of sleep.
  • Stage 4 (REM). REM sleep is the cycle where you’re most likely to dream and is characterized by paralyzed muscles and quickly moving eyes. It usually begins about 90 minutes after you fall asleep, and during each cycle throughout the night, it gets longer.

Sleep deprivation can negatively impact your judgment and your ability to assess your cognitive ability. Not getting enough sleep puts you at risk of making poor decisions, such as driving when not mentally alert.

Regularly getting less than 6 hours of sleep increases your risk of falling asleep at the wheel by 260 percent compared to regularly getting 7 to 9 hours. Sleepy driving also accounts for about 1 in 6 fatal crashes.

Not getting adequate sleep over a long period can negatively impact a variety of aspects of your health. Chronic sleep deprivation puts you at a heightened risk of:

According to the CDC, adults should aim for at least 7 hours of sleep each night.

Getting enough sleep every single night can be challenging. Life gets busy, and things can crop up last second—you may be cramming for an important exam or taking care of your children.

However, external factors aside, if you are routinely finding yourself in a position where you have to make a decision between sleeping 1 to 2 hours or not at all, there are a few things you can do to make getting good sleep easier:

  • go to bed and get up at the same time every day, even on weekends
  • keep your bedroom quiet and at a cool temperature
  • avoid large meals and alcohol right before bedtime
  • avoid caffeine in the afternoon and evening
  • refrain from using electronic devices at least 30 minutes before bedtime
  • exercise regularly
  • eat a healthy diet

Collectively, these habits are called sleep hygiene. Practicing good sleep hygiene is associated with long-term sleep improvement.

If you are in a situation where you have to choose between getting very little sleep or getting none, it’s better to opt for some sleep.

Ideally, you should try to get more than 90 minutes of sleep. Sleeping between 90 and 110 minutes gives your body time to complete one full sleep cycle and can minimize grogginess when you wake.

But any sleep is better than none at all — even if it’s a 20-minute nap.