Despite being a huge part of our lives, there is a lot about sleep that remains a mystery
It’s no secret that we all need sleep. While nutrition and exercise often take the headlines in terms of health and wellbeing, sleep is the foundation upon which all other pillars of health are built. High quality, restorative sleep gives our brains and bodies a chance to slow down and recover, promoting better health in both the short and the long term.
But despite its importance and its prevalence in all of our lives, many people still don’t fully understand what sleep involves. We’re going to take a closer look at the science behind sleep, exploring what happens when we sleep, and the impact it has on your brain and body.
What does sleep involve?
As you sleep, you progress through four to five sleep cycles (depending on how long you are in bed for), each of which is made up of four sleep stages. What’s more, each of these four sleep stages can be further broken down into two categories: REM (rapid eye movement) sleep and non-REM sleep.
REM and non-REM sleep differ dramatically. The first three sleep stages are made up of non-REM sleep. Stage one is short, and involves dozing off and transitioning into sleep, while stage two allows the body and mind to slow – from breathing to heart rate to brain activity. During these two stages, you’re most susceptible to being awoken or disturbed.
Stage three is deep sleep, during which your body enters recovery mode. Your brain activity also slows dramatically. Conversely, the fourth stage of sleep is REM sleep. Brain activity increases during this time and this is the period in which you dream. Breathing and heart rate increase during REM sleep and most muscles are paralysed, which keeps us from acting out these dreams.
Each sleep cycle lasts anywhere between 70 and 120 minutes. During the first few cycles, more time is spent in non-REM sleep, as the majority of REM sleep occurs in the second half of the night.
How does sleep impact our brain and body?
Every part of your body is impacted by sleep, with thousands of neurons in the brain switching from a waking to a sleeping state. Both your breathing and heart rate slow as you transition into sleep, and your brain waves drop dramatically when you enter non-REM sleep. As you move into REM sleep, however, brain activity accelerates.
Experts believe that REM sleep is important to humans because the process supports our critical cognitive abilities, including memory consolidation. Non-REM sleep, meanwhile, is thought to facilitate proper brain function, helping the brain store new information and remove toxic waste.
Sleep also plays a significant part in healthy hormone release. These include melatonin, which helps to promote sleep, as well as growth hormones for bone and muscle health, and cortisol which is part of the body’s stress response system. Sleep also helps with the release of leptin and ghrelin, which are influential chemicals in the control of appetite through the day. This makes healthy sleep an essential part of any weight management effort, as it also provides you with the energy you need to stay active.
Prioritising your sleep health can benefit your physical and mental health in the long run. By creating a sleep schedule, giving yourself time to unwind in the evening, and investing in high-quality bedding, you can enjoy better sleep and better health overall.