We all know how lousy it feels when you don’t sleep well, but science tells us it can be a health risk, too. During sleep, your body not only repairs muscles, it removes plaque and waste created in the brain, and it processes emotions and stores memories. Not getting the recommended 7–9 hours a night hurts concentration, memory, coordination, and mood. Over time, sleep deprivation raises your risk for weight gain, high blood pressure, and heart disease, and also lowers your immunity. It can even make you more vulnerable to mental health issues, including depression and anxiety. You need good sleep. There’s evidence that the quality of sleep matters as well. Healthy adults need 1 ½ to 2 hours of deep “slow-wave” sleep per night, which is about 20 percent of your total sleep. Wearing a Fitbit Versa or Oura Ring for a week will help you discover where you are, sleep-wise—without a trip to a sleep lab. So, we know that sleep makes us feel better, and we know it’s better for us. And we even know how to measure our deep sleep. But how do we get it? …