3. Cell phones
This is one of those controversial subjects for which you can find studies landing on both sides of the issue, depending on the particular bias of the research.
Electromagnetic fields exude radiation and we know that exposure to radiation in close proximity and for extended periods is detrimental to human health. At the very least, sleeping with your cell phone next to your bed is distracting and can disrupt sleep.
A Swedish study found that the radiation from a cell phone can also cause headaches and confusion. (5, 6) Another recent study established a definite link between cell phone radiation and cancers, including brain tumors. (7)
Use a headset and limit cell phone use, turning it off and putting it as far away from you as possible as often as possible.