At any age, sleep is critical for good health, especially to build up your immune system.

These days, we’re all thinking about our body’s ability to protect itself against viruses and disease. A strong immune system needs plenty of sleep. One simple way to boost immunity is by getting lots of ZZZ’s — sleep, that is. But how much sleep?

CDC guidelines state that adults need 7 or more hours of sleep each night for the best health and wellbeing. However, it found that 35% of adults don’t get a minimum of 7 hours each night. That’s one-third of the population. Fortunately, there are things you can do to boost your sleep hygiene and your overall immunity.

Screen-free wind-down

To get more sleep or even just fall asleep faster, begin a screen-free wind-down each evening. That is, turn off your cell phone several hours before bedtime. It’s just that easy — because digital devices emit blue light which suppresses the sleep-inducing hormone, melatonin. While you’re at it, also shut down your tablet and computer. They’re also culprits in stealing sleep. At a minimum, consider using a blue-light blocker for your devices.

Read, soak, relax

Other typical ways to prepare for slumber are to curl up with a good book or take a hot bath. Both help you relax and unwind, so when the lights go out, your mind and body are already at rest.

The value of sunshine and exercise

Here are two surprising, but important, factors in getting a good night’s rest. Exercise! Studies show that exercise during the day can help you sleep better at night. But be careful not to get too active close to bedtime — that can have the opposite effect and wind you up.

Also, be sure to get some sunlight each day. A small study of seniors found that just two hours of sunlight in the morning for five days in a row significantly improved sleep quality.