#13 – Sleep in Darkness
Although most people sleep in completely dark rooms, there are still some people out there who sleep in lit bedrooms. Sleeping in a lit bedroom is especially bad for women because it, as the studies have found out, increases the chances of developing breast cancer. Now, this has to do something with melatonin.
When you sleep in a bedroom with a lamp turned on, the light exposure will suppress your melatonin levels. This will, in turn, make damage to your estrogen levels and can lead to breast and ovarian cancer.