What happens when we sleep?

Sleep is regulated by your circadian rhythm, or body clock, located in the brain. The body clock responds to light cues, ramping up production of the hormone melatonin at night and switching it off when it senses light.

Every night, almost everyone on the planet enters a state of unconsciousness and paralysis. But what is really happening inside the body when we drift off, and what's the impact if we don't get enough sleep? Sleep is regulated by your circadian rhythm, or body clock, located in the brain. The body clock responds to light cues, ramping up production of the hormone melatonin at night and switching it off when it senses light.

There are four stages of sleep that the body experiences in cycles throughout the night. On a good night, we cycle through these stages four or five times. Stages one and two are light sleep. This is a transition from being awake to falling asleep. Heart rate and breathing begin to slow, body temperature falls, and muscles may twitch. Stage three is sometimes referred to as delta sleep because of the slow delta brainwaves that are released during this stage. This is the first stage of deep sleep where our cells produce the most growth hormone to service bones and muscles, allowing the body to repair itself. Stage four is where we begin to dream. The body creates chemicals that render it temporarily paralyzed so that we do not act out our dreams. In this stage, the brain is extremely active, and our eyes, although closed, dart back and forth as if we were awake.

Humans roughly spend one-third of their lives asleep. Modern lifestyles, stress, and the proliferation of technology mean that people are sleeping far less today than they were a century ago. Sleeping less than seven hours per day is associated with an increased risk of developing chronic conditions, which could reduce life expectancy. So, for a healthier, longer life, get some shut-eye.

There are four stages of sleep that the body experiences in cycles throughout the night. On a good night, we cycle through these stages four or five times. Stages one and two are light sleep. This is a transition from being awake to falling asleep. Heart rate and breathing begin to slow, body temperature falls, and muscles may twitch. Stage three is sometimes referred to as delta sleep because of the slow delta brainwaves that are released during this stage. This is the first stage of deep sleep where our cells produce the most growth hormone to service bones and muscles, allowing the body to repair itself. Stage four is where we begin to dream. The body creates chemicals that render it temporarily paralyzed so that we do not act out our dreams. In this stage, the brain is extremely active, and our eyes, although closed, dart back and forth as if we were awake.

Understanding the stages of sleep and the critical role of the circadian rhythm helps us appreciate the importance of getting enough rest. For a healthier, longer life, it's essential to prioritize sleep and maintain good sleep hygiene. By doing so, we can support our body's natural processes and reduce the risk of chronic health issues. So, make sure to get some shut-eye and give your body the rest it needs to function optimally.