A lack of sleep can make you irritable, undermine brain function, and put you at greater risk of injury.
Some of the most innovative minds of recent generations pride themselves on being awake at all hours. Elon Musk works until 1am before starting his next day at 7am. Richard Branson functions on five to six hours sleep a night.
However, evidence has emerged showing what sleep deprivation can do to your brain and body. Science is telling us more about how adequate sleep can help you retain more information, maintain a healthy body weight, and keep your brain at optimum functioning capacity.
The physical effects of under-sleeping
We all know the feeling when we haven’t had enough sleep: brain fog, moodiness, and inability to concentrate. The physical effects of a lack of sleep have been confirmed by various studies. A comprehensive study on sleep deprivation published in Neuropsychiatric Disease and Treatment in 2007 showed people who experienced sleep loss suffered a noticeable decline in cognitive performance and unpredictable changes in mood.
Prior to this, studies conducted between 1999 and 2005 found sleep loss may also activate the sympathetic nervous system, which can lead to a rise in blood pressure and cortisol secretion. This impairs our immune response and causes metabolic changes in the body, such as insulin resistance, which can lead to weight gain.
Increased risk of injury
Ever tried playing sport on a few hours sleep? You probably noticed your coordination was off. A lack of sleep causes lowered cognitive function, meaning we don’t have the necessary mind-muscle connection that difficult exercise movements require. You are at far greater risk of executing a movement poorly and injuring yourself. It’s a recipe for disaster for amateur athletes stepping onto a sports field or inside a gym.
Sleep is also the prime time for the body to recover. Doing more exercise on under-recovered muscles can turn relatively normal “soreness” into something more sinister.
The benefits of adequate sleep
A systematic review of more than 1,000 studies on sleep published in Physiological Reviews in 2013 analysed the role of sleep on memory and the effects it can have on cognitive ability. The results found that, in certain stages of our sleep, we practise and rehearse skills and information we have learned.
During the deepest stages of sleep, known as rapid eye movement (REM) sleep, the part of the brain that is involved in learning new skills and memory becomes hyperactive. During this phase, the brain practises skills and memory over and again, faster than you ever could when awake. This goes for both intellectual and physical skills, which is why sleep is so important for everyone from PhD students to athletes. It’s why all-star US basketballer Lebron James prides himself on sleeping for up to 10 hours each night.
The process your brain undergoes during REM sleep is like backing up a computer hard drive: it’s vital to protect the information stored inside. However, if you interrupt the process, you could create a glitch in the memory system and lose all your important files.
How much sleep is enough?
The need for sleep varies considerably between individuals, but most studies agree that a good average is between seven and nine hours per day. Next time you’re staring at a screen and depriving yourself of sleep, think about what you are sacrificing in terms of your work productivity, health and fitness. Instead of bingeing on Netflix for three hours, take a nap instead.