Increased risk if low temp/wind chill/moisture, age extremes, med conditions, alcohol/drug use, longer exposure, poor clothing, and activity level (movement makes heat but can only do for so long without fuel); Have internal temp under 95 F, cold skin, and AMS; initially shiver, goosebumps, and increased metabolic rate as compensatory mechs; if alert, actively warm; if no, passively warm; ALS