WHAT IS SLEEP?
Sleep is the primary human behaviour. We spend about one third of our life sleeping!
This human behaviour tales so much time because it plays a crucial role for our brain, our body and our life.
Contrary to what we might think, our brain is not inactive during sleep. It is differently-active. It allows memory and endocrinal (hormonal for example) regulation and neurone regeneration.
The brain also produces new neuro-transmitters, memorises, consolidates learning and regulate the majority of our daily activities.
The body also regenerates. Don’t we tell children that if they sleep well they will grow up? The body regenerates, rests and produces new protein.
THE SLEEP CYCLES
Sleep is organised in cycles. The cycles in humans are made of slow-wave and REM sleep (Rapid Eye Movement). REM is known for being the dream phase.
The cycles are made of deep sleep phases followed by REM sleep over a 90 minutes period. During one night, an adult will go through an average of four sleep cycles.
The deep sleep offers more of a physical recovery function and the REM sleep phases consolidate memory and regenerate our intellectual, neurological and endocrinal functions.
HOW MANY HOURS OF SLEEP DO WE NEED?
A newborn sleeps most of the time. Over 18 hours per 24 hours period.
A child’s sleeping needs are still very important: 12 hours out of 24, to enable his physical and neurological development.
We must however understand that even teenagers need between 10 and 11 hours of sleep per night, which is very difficult to achieve in our society.
An adult needs 7 to 8 hours of sleep per night.
Contrary to popular belief, older people still need 6 to 7 hours of sleep per night but their sleep is more fragmented and spreads over the 24 hours. Sleep fragments with age and an elderly will experience more awakened hours during the night and need to nap during the day. This makes us think that an older person needs less sleep.
We see here that sleep requirements remain quite stable from adulthood. It is important to keep them as such.
WHAT HAPPENS WHILE WE ARE SLEEPING?
The majority of our physiological functions change while we are sleeping.
Our breathing is softer, our heart rate and blood pressure reduce and our muscles relax and recover.
We also restore our neuro-transmitters potential to function properly during the day.
We produce some regulatory hormones, including the growth hormone responsible for tissue repair and growth in children.
Furthermore, sleep regulates appetite. Some of the modern problems we are faced today such as overweight and obesity are greatly influenced by the quality of our sleep.
WHAT HAPPENS WHEN WE DO NOT GET ENOUGH SLEEP?
Sleep deprivation, experienced by the majority of the population, has physiological effects since we do not allow the physical and mental regulations to occur.
This is when appetite regulation and obesity problems appear.
Sleep deprivation leads to physiological troubles. We do know that people who do not get enough sleep are at risk of depression, anxiety and neurological disorders. Some of the symptoms of these disorders are: memory disorders, concentration disorders and mood disorders.