What Happens When You Sleep?

Home >> How Sleep Works >> What Happens When You Sleep?

addition, levels of the hormone cortisol dip at bed time and increase over the night to promote alertness in morning.

Sleep helps us thrive by contributing to a healthy immune system, and can also balance our appetites by helping to regulate levels of the hormones ghrelin and leptin, which play a role in our feelings of hunger and fullness. So when we’re sleep deprived, we may feel the need to eat more, which can lead to weight gain.

The one-third of our lives that we spend sleeping, far from being “unproductive,” plays a direct role in how full, energetic and successful the other two-thirds of our lives can be.