5. Use of electronic devices
At least 2-3 hours before bedtime, NASA astronauts stop using electronic gadgets. Our body needs melatonin, a sleep hormone that controls the sleep cycle. Computer screens, tablet screens and smartphones emit a blue light that reduces the production of melatonin.
There are apps that you can use to reduce the blue light and increase the warm light on the screens before bedtime. In some devices like iPhones, this facility is built-in.