To keep beating a dead zombie here, 'cause I like beating dead zombies, the best flat out method is having someone you know with you. Next is a med-alert bracelet bracelet of some kind.
Ever since I bought a medical alert bracelet and had it engraved, which is nearly two months ago, I have been wearing it every day. Given its location, my left wrist, any rescue personnel will quickly discover it and yet as a bracelet it looks fashionably acceptable for everyday situations.
Jeanette Isabelle