Did you know that even one poor night’s sleep can depress your immune system functioning by up to 30 percent? When you feel any kind of illness coming on, its important to get as much rest as possible. Every individual differs, some may need their full 8 Hours and some may need less. Lack of sleep can affect your immune system. Studies show that people who don’t get quality sleep or enough sleep are more likely to get sick after being exposed to a virus, such as a common cold virus.