Q: I’m having trouble sleeping lately. Does this increase my chances of getting sick?

Yes, lack of sleep can affect your immune system. Studies show that people who don’t get a good night’s sleep or who don’t get enough sleep are more likely to get sick after being exposed to a virus, such as the common cold. Lack of sleep can also affect how fast you recover if you do get sick.

During sleep, your immune system releases proteins called cytokines. These substances increase in the presence of an infection, inflammation and stress. Increased cytokines are necessary in fighting infection and regulating deeper sleep. In addition, other infection-fighting cells are reduced during periods of sleep deprivation. So, your body needs sleep to fight infectious diseases.

How much sleep do you need to bolster your immune system? The optimal amount of sleep for most adults is seven to eight hours a night. School-aged children and adolescents need nine or more hours of sleep a night.

But be careful; more sleep is not always better. For adults, sleeping more than nine to 10 hours a night has been associated with weight gain, heart problems, stroke, sleep disorders, depression and other health concerns.