Sleeping is your body’s way of repairing and recovering so it can perform like a well-oiled machine. It’s less an act of lounging and more so a tool for your brain at large. 

“Sleep clears toxins and waste that build up across the day. It also refines neural connections and prioritizes those we use often (as well as new information),” explains Major Allison Brager, Ph.D., a neuroscientist involved in the U.S. Army’s Holistic Health and Fitness System specializing in sleep.

Sleep is also vital for replenishing your physical and neural energy, Brager notes, and allows the neuron clusters that make up our nervous systems the opportunity to take turns going “offline.” In other words, not sleeping well can affect all of your mental faculties, affecting how you feel and operate both mentally and physically. 

That being said, board-certified sleep specialist Michael J. Breus, Ph.D., affectionately known as the Sleep Doctor, tells mbg it does take more than one night of poor sleep to majorly affect your quality of life. It can, however, leave a mark on your mood and productivity the next day. Here are some expert-approved tips to handle the lingering sleepiness.