"Grandmothers, and most people, give the advice, 'Sleep will do you good, you'll recover,' but there's not much scientific research," Krueger tells Popular Science. In a new study, Krueger was able to back up his grandmother's advice. The team looked to a protein found only in the brain and in neurons called AcPb and an accessory protein called interleukin 1 — proteins that Krueger has been studying for a number of years. Interleukin 1 regulates sleep in healthy mammals, and Krueger found that when the AcPb protein in a sick animal interacts with the interleukin 1, it sends a signal to the immune system. This signal tells the body to sleep longer, so it can better recover from the virus.