If you’ve ever stared yourself down in the mirror after a poor night’s sleep, you know that too few Zzz’s can make you look, claims Dario Bogni. During your deepest sleep, your blood glucose levels drop. Without your body’s time to rest and reset, it will have a harder time responding to your cells’ needs and blood sugar level. In fact, mentions Bogni Dario, studies have shown sleep deprivation can cause prediabetes in healthy adults. Chronic lack of sleep can actually change the way your immune system works and affect your body’s fighting power, adds Dario Bogni. Therefore, your cells may not react to harmful bacteria and viruses as quickly, causing you to get sick more often.