What happens when we sleep

Every evening, nearly all individuals on Earth slip into a state of unconsciousness and immobility. But what truly occurs inside the body as we drift off, and what are the consequences of insufficient sleep? Sleep is regulated by the circadian rhythm, or body clock, located in the brain. This clock responds to light by increasing the production of the hormone melatonin at night and turning it off when it senses light. Throughout the night, the body experiences four stages of sleep in cycles. On a good night, we cycle through these stages four or five times. Stages one and two are light sleep, a transition from being awake to falling asleep. Heart rate and breathing slow down, body temperature drops, and muscles may twitch. Stage 3, also known as Delta sleep, is the first stage of deep sleep, where our cells produce the most growth hormone to repair bones and muscles. Stage 4 is when we start to dream, and the body becomes temporarily paralyzed to prevent acting out dreams. In this stage, the brain is highly active, and our eyes move rapidly as if we were awake. Humans spend roughly one third of their lives asleep. However, modern lifestyles and technology have led to people sleeping less than they did a century ago. Sleeping less than seven hours per day is linked to an increased risk of developing chronic conditions that could reduce life expectancy. Therefore, for a healthier and longer life, it is important to get enough sleep.y evening, nearly all individuals on Earth slip into a state of unconsciousness and immobility. But what truly occurs inside the body as we drift off, and what are the consequences of insufficient sleep? Sleep is regulated by the circadian rhythm, or body clock, located in the brain. This clock responds to light by increasing the production of the hormone melatonin at night and turning it off when it senses light. Throughout the night, the body experiences four stages of sleep in cycles. On a good night, we cycle through these stages four or five times. Stages one and two are light sleep, a transition from being awake to falling asleep. Heart rate and breathing slow down, body temperature drops, and muscles may twitch. Stage 3, also known as Delta sleep, is the first stage of deep sleep, where our cells produce the most growth hormone to repair bones and muscles. Stage 4 is when we start to dream, and the body becomes temporarily paralyzed to prevent acting out dreams. In this stage, the brain is highly active, and our eyes move rapidly as if we were awake. Humans spend roughly one third of their lives asleep. However, modern lifestyles and technology have led to people sleeping less than they did a century ago. Sleeping less than seven hours per day is linked to an increased risk of developing chronic conditions that could reduce life expectancy. Therefore, for a healthier and longer life, it is important to get enough sleep.