Sleep impacts our health in every area but researchers have recently found sleep's greatest benefit to be physical: cleansing. Our body has a great system for flushing out waste, the lymphatic system, but it does not extend to our brain. As the brain tightly regulates everything, it is kept highly secure behind the blood-brain barrier to avoid contamination, but it does have waste to get rid of.
The brain has its own disposal system, the Glymphatic System which pumps cerebral spinal fluid, CSF, through brain tissue to remove waste. The waste is then flushed into our circulatory system, then into our lymphatic system where it is flushed out of our body with all other waste. The Glymphatic System requires a lot of energy and seems to be about 10 times more active during sleep. This is why our brain uses as much energy when we are asleep as it does when we are awake. Brain cells also shrink up to 60% during sleep so CSF can wash through faster. Waste build up has links to serious brain diseases like Alzheimer's. If we don’t sleep every night, our brain can't cleanse itself of toxins properly.
Missing sleep can interfere with attention, awareness, ability to process information, reasoning and problem solving skills. When tired we are more easily distracted, less able to implement new strategies, less able to confront new situations, far more reliant on habit (doing what we have always done) and less able to control our mood and performance. When tired, emotional capacity is diminished which may result in an inability to handle stress, less control of our moods and performance, being easily upset over trivial things, moodiness or mood swings, increased depressive feelings and burnout, decreased empathy, being more likely to pick a fight, relationship troubles, agitation, decreased libido, irritability or aggression, anxiety, sadness, slumps in attention, thinking and focus, sluggish behaviour, hunger, zoning in and out, and mood swings.