Along with diet and exercise, sleep is one of the three key pillars of health,. But while we often discuss food and physical fitness, sleep gets far less focus. After all, a little tiredness didn’t hurt anybody, right? Wrong!
Inadequate sleep affects an estimated 7.4 million Australian adults, costing our economy over $45 billion annually.
Lack of sleep – whether it’s due to working late hours, social commitments, or sleep disorders like insomnia – not only makes you groggy and cranky, but it can also put your overall health at risk.
On World Sleep Day, Prerna Varma and Hailey Meaklim, PhD researchers in the RMIT Sleep Lab, explain just what happens to your brain and body when you are sleep deprived.
1. Your cognitive performance diminishes
You need sleep to recharge your brain. Being tired and not sleeping well disrupts genes that govern circadian rhythm, effectively reducing your ability to perform a task.
It also affects your memory and your ability to retain information. Lack of sleep reduces activity in your hippocampus – the memory centre of the brain. So you might pull an all-nighter to study for an exam, but forget details on the day because your hippocampus didn’t encode those memories.
Even one night of partial sleep deprivation impacts your executive functioning. In brief, sleep loss can impair attention and concentration, reducing your capacity for reasoning and problem solving.
2. Your reaction time is reduced (and your risk of accidents increases)
Have you every decided to stay awake late into the night to complete an assignment, but woken up the next morning with only 10 sentences on your screen? That’s probably because your body experienced “microsleeps”, brief episodes of sleep while you are awake.
Microsleeps usually occur when you are sleep deprived (due to a build-up of homeostatic sleep drive), getting longer until you get full sleep. This prevents you from being alert and reduces reaction time, sometimes with dire consequences.
More than one Australian dies every day due to drowsy driving or industrial accidents related to sleep deprivation. Sleep loss often results in reduced awareness of the environment and situations.
3. Your mood is disturbed (and so are your emotional responses)
Grumpy, cranky, tired or just plain annoyed after a bad night of sleep? You are not alone!
Regular sleep loss can increase negative mood states, which basically means you might feel more irritable. It can also lead to problems with relationships.
In fact, depression is overrepresented in people with sleep disorders, and insomnia is a risk factor for developing or recurring depression. Treating sleep problems can help with reducing depression and its symptoms.
That’s not all! Sleep deprivation not only affects your mood, but also your ability to interpret and understand emotional signals.
For instance, after one night of sleep deprivation, participants in a study had trouble distinguishing whether facial expressions were threatening or non-threatening. Sleep deprivation can impair the central and peripheral nervous system, making you perceive others as threatening.
4. You risk developing serious health problems
Sleep loss can put you at risk for heart disease, high blood pressure, diabetes, obesity and several other chronic medical conditions. A greater degree of sleep deprivation is possibly associated with greater adverse effects on health. For example, sleep loss leads to an increase in ghrelin levels, a hormone responsible for stimulating appetite.
There is also a relationship between shorter sleep time and impaired glucose tolerance, a key issue in diabetes. Large population studies indicate increased risk of heart attacks and strokes related to sleep loss. Poor sleep is associated with lower life expectancy.