Sleep has a profound impact on the immune system. During sleep, the body undergoes various restorative processes that are crucial for maintaining optimal immune function. For instance, certain cytokines, which are proteins that help regulate the immune system, are produced and released during sleep. These cytokines play a vital role in fighting off infections and inflammation. Lack of adequate sleep can lead to a decrease in the production of these cytokines, making the body more susceptible to illnesses.