The catch, of course, is that as the waters get quieter, the weather is getting colder. Go out ill prepared and your ride may not only be less fun, but downright dangerous. Body temperature can easily drop when submerged in cold water or exposed to the elements without protection. Fail to bring that body temperature back to normal and hypothermia can quickly set in. Looking for signs? Shivering, high blood pressure, faster-than-normal heart rate, and rapid breathing are all symptoms of mild hypothermia; lowered body temperature and more violent shivering signal it has progressed to a moderate stage. Severe hypothermia is typified by heart rate, respiratory rate, and blood pressure all decreasing.