During sleep, our immune systems work to produce disease-fighting cells, our bodies repair cell and tissue damage, our brains organize and store memories from the day, hormones that control our various brain and body functions rebalance, and we "recharge" our brains, so we feel more emotionally balanced.
But what happens if you don't get enough sleep?
Unfortunately, a lack of quality sleep can lead to many physical and mental health issues, some of them life-threatening. Here are just a few:
Impaired mental functioning -- Lack of sleep can affect concentration and memory, and can affect your ability to perform daily tasks.
Stress and depression -- Lack of sleep increases the activity of the hormones and pathways in the brain that cause stress, and changes in sleeping patterns have been shown to have significant effects on mood. Ongoing insomnia may be a sign of anxiety and depression.
Heart disease -- People with chronic sleep loss show signs of heart and nervous system activity that might put them at risk for heart disease.
Headaches -- Headaches that occur during the night or early in the morning may be related to a sleep disorder.
Weakened immune system -- Because sleep helps regulate your body's response to infection, a lack of sleep can lead to more colds and other illnesses.
Diabetes -- Your body's ability to regulate blood sugar levels is impeded, which may double your risk for type 2 diabetes.
High blood pressure -- People who don't get enough sleep are more likely to develop high blood pressure possibly due to their elevated levels of the stress hormone cortisol, which strains the heart.
Cancer -- Sleeping fewer than six hours each night results in a 60 percent increase in breast cancer risk, according to researchers at the Tohoku University Graduate School of Medicine in Japan.