There is nothing quite like laying your head down on the pillow at night, feeling yourself drift off into another cozy night of rest. It is even better when you wake up feeling renewed and ready for the day. Sleep is an essential part of the human experience but remains quite a mystery when it comes to health science.

Here is what we know for sure:

Within minutes of falling asleep, there are significant changes in both the brain and body. Your body temperature drops, brain activity slows, along with your heart rate and respiration. Sleep scientists have narrowed down the four stages of sleeping, each lasting anywhere from 70 to 120 minutes.

In the first stage, which occurs in the first five minutes after falling asleep, all body systems are impacted by a good night’s sleep on comfortable mattresses, then transitioning into stage two, where similar things occur, but at a higher rate. It is easier to wake up at this time.

The third stage is where your body is relaxed, and the brain has the slowest activity. The third stage is the deepest part of non-REM (rapid eye movement) sleep. Deep sleep is a key part of repairing the body and assists with memory. The final stage is the only stage of REM sleep, where your brain picks up activity, and most of the body goes through temporary paralysis, except your eyes and muscles used for breathing. This is where dreams usually happen.

Most people spend most of their sleeping time in REM, occurring more often in the later parts of the night. Each person will experience all four stages, but how long they stay in them and what changes in the body occur will depend on external factors such as activity levels and sleeping environment.

Looking for a better night of rest? Hastens mattresses are designed specifically to help you fall asleep and stay asleep all night. Try out the Hastens experience at Brickell Mattress, located in the heart of Miami on Calle Ocho.