I don't like a radio transmitter close to my head for several hours while I'm sleeping
Turn WiFi & BT off and you drastically reduce the emissions - mobile phone heartbeat signals are remarkably power efficient. If paranoid, put the thing into flight mode and turn all the radios off. The clock will still work and you can still benefit from the flexible alarm settings - I need them and going back to a normal alarm clock would be both tedious and risk my being late (or - worse - early) out of bed some days.
Bonus of not getting alerts during the night. Once is enough to be woken up at 3am by a bounced email finally coming home to roost.
M.
Biting the hand that feeds IT
