That’s what sleep is: essential. By means of following up to yesterday’s post, here’s why (taken off of a handout from my gym):

1. It makes you HEALTHY
Skimping on shut-eye has the potential to be deadly: “Chronic sleep debt raises your risk for high blood pressure, heart disease, diabetes, and obesity,” says Dr. Emsellem. Your immune system is compromised too, “so you’re more susceptible to catching every virus that comes along.”

2. It makes you SMARTER
Though your body shuts down, your brain buzzes with activity as you sleep. That’s when it sorts, processes, consolidates, and stores the masses of information you absorbed during the day. “Sleep is crucial for learning, cognition, memory, and performance,” says Dr. Epstein. In fact, a Harvard study showed that adults who got a good night’s sleep performed 44 percent better on a memory test 12 hours later, compared with those who stayed awake.

3. It makes you SLIM
Recent research reveals “a very close relationship between insufficient sleep and the inability to lose or stabilize weight,” says Dr. Emsellem. A likely reason: Sleep debt interferes with the function of hormones that regulate how efficiently the body burns fat.

4. It makes you COORDINATED
Harvard scientists have found that after trying a new motor task–playing a piano minuet, doing an aerobics routine–a good night’s rest solidifies what you’ve learned, making it easier and more automatic the next day. “Studies show that your brain replays the same sequences during the night,” explains Dr. Emsellem. “The next day, you just know the moves–it’s no longer a conscious act.”

So make like Nike and just do it!