Twenty-four hours without sleep dysregulates our immune system, increases inflammatory proteins, and raises blood cortisol and adrenaline levels (stress hormones). This means that when we get insufficient sleep, we are more likely to feel stressed and overwhelmed when facing even minor challenges. Twenty-four hours of sleep deprivation also reduces concentration and working memory, and increases the likelihood of making mistakes.
If normal sleep is restored, these changes will revert back to baseline levels within a few days. If sleep deprivation is a frequent occurrence, it can lead to the development of high blood pressure, obesity, type 2 diabetes, heart disease, stroke and eventually, dementia.
In a particularly enlightening study, 12 healthy men and women aged between 19 and 39 were randomly assigned to one of two sleep situations. In one instance, they were allowed only 4 hours of sleep for 14 consecutive days. After a three-month recovery period, they were allowed up to 9 hours of sleep for another 14 days. Throughout both experimental situations, their food intake, energy expenditure and body fat levels were monitored. During the period of sleep deprivation, participants consumed 300 more Calories per day, with no change in their energy expenditure. CT scans showed that this produced an 11% increase in visceral fat. Visceral fat (VAT) refers to fat that accumulates in and around our abdominal organs such as the liver, pancreas, kidneys and intestines. VAT is chemically different from the fat that is deposited under our skin (subcutaneous fat). VAT releases pro-inflammatory molecules called cytokines that contribute to the development of just about all chronic diseases. Normally, fat is preferentially stored under the skin, but sleep deprivation diverts fat to a much more dangerous location.
Other studies have found that sleep restriction causes the brain to react more intensely to visual food cues, especially to unhealthy food. This makes us more likely to opt for sweets and processed foods when we haven’t had enough sleep. Willpower doesn’t stand a chance against lack of sleep.
There will be times in our life when sleep deprivation is difficult to avoid (as any parent of a newborn will attest), but the message is to prioritise a good night’s sleep as often as possible. Sleep not only improves every aspect of our physical and mental health, it makes life feel easier and more fun.
For those who would like to read the original research papers, here they are:
- Impact of sleep deprivation on monocyte subclasses and function — 10.1093/jimmun/vkae016
- Adverse Effects of 24 Hours of Sleep Deprivation on Cognition and Stress Hormones — http://dx.doi.org/10.3988/jcn.2012.8.2.146
- Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity — https://pmc.ncbi.nlm.nih.gov/articles/PMC9187217/pdf/nihms-1787089.pdf
- Sleep restriction leads to increased activation of brain regions sensitive to food stimuli — https://pmc.ncbi.nlm.nih.gov/articles/PMC3302360/pdf/ajcn9540818.pdf
- Sleep restriction increases the neuronal response to unhealthy food in normal-weight individuals — https://pmc.ncbi.nlm.nih.gov/articles/PMC3883872/pdf/nihms524446.pdf
Please share this Health-e-Byte with anyone who thinks they don’t need much sleep.
