We’ve all heard that there are different stages of sleep and which one you wake up in could determine whether you rise refreshed or on the wrong side of the bed. So what exactly are the stages of sleep and how can you set your morning alarm to take advantage of them for more energy?

In the first stage, you start to drift off. You might feel like you’re falling or experience jerking. This is called hypnic myoclonia and totally normal. During this stage you will find yourself drifting in and out of consciousness. 

During stage two, your heart rate and breathing begin to slow and your body temperature drops. You will spend about half your sleep in this cycle and your brain will begin to generate “sleep spindles,” or rapid bursts of brain activity that regulate sleep.

Stage three is also known as deep sleep. This is the stage where your body is restored, including muscle and tissue growth. Cell repair happens at this time and your brain creates delta waves, which is why this stage is also sometimes called delta sleep. If you wake during deep sleep, you will likely feel groggy and disoriented. 

Lastly, REM, or rapid eye movement, sleep is when our dreams occur. This is when our memories are consolidated and our brains recharge. Contrary to the other stages, during REM, your breathing and heart rate goes up and your body stops moving to prevent you from acting out your dreams. The first REM cycle usually lasts about 10 minutes and occurs every 90 minutes, but they increase in length as the night goes on. The average adult experiences four to five REM cycles each night, but the time we spend in REM decreases as we age. While babies can spend up to 50 percent of their sleep in this stage, adults average about 20 to 25 percent in REM.

So when should you wake up? It’s important to note that the cycles don’t occur in order. We go through Stage 1, 2, and 3, then back to 2, before entering REM sleep. It’s ideal to wake up at the end of a cycle as this is what our bodies would naturally do if we were to sleep in a quiet space without an alarm. The most effective way to avoid morning grogginess is to determine the number of hours you need to feel rested, usually between seven and nine for adults, and stick to a set number. This also means going to bed and waking up at relatively the same time each day.