While sunscreen and life jackets may be at the top of your list for staying safe in the water, there's another thing you should be cautious of: the water temperature. Swimming expends lots of energy and if the water temperature isn't within a certain range, it won't allow your body to function properly, possibly leading to some serious problems. Even if the temperature isn't extremely hot or cold, the wrong temperature can turn a good time in the water into a life-threatening event.
Your age, weight and what type of swimming you're planning on doing — such as leisurely laps or vigorous racing — determine the temperature considered safe for you. For lap swimming or racing, the temperature should rage from 78 to 82 degrees. For children and older adults, higher temperatures ranging from 82 to 86 degrees are suggested. For the obese, the water should be between 80 and 86 degrees, while pregnant women require temperatures between 78 and 84 degrees. Since babies are smaller, they have a hard time regulating their body temperatures, which means the water should be 84 to 86 degrees. Of course, this assumes a healthy person; if you have any health conditions, check with your doctor to determine the right temperatures for you (or if you should be swimming at all).
Cold water zaps your body heat 25 times quicker than cold air. Add to that the physically exhausting nature of swimming, and you're losing body heat at a rapid pace. Extremely cold water — 50 degrees or below — can lead to cold shock. This occurs when the body is overwhelmed by extreme cold, and it can send your body into a heart attack or unconsciousness, the latter of which can lead to drowning. Your body responds to a sudden plunge into cold water by making you involuntarily gasp, and if you're under water this can cause you to drown before you get to the surface.
You're probably well aware of hypothermia, which occurs when the body loses heat at a rapid pace. This can also occur in cold temperatures of 50 or below. While hypothermia takes longer than cold shock, it can be just as serious. Exposure to cold water for long periods of time lower your core body temperature. The lower it gets, the less your body can function. Once your core temperature reaches 93 degrees, you'll be unable to use your arms and legs, and your mental function begins to deteriorate. At 80 degrees, you can become unconscious and drown.
On the flip side of hypothermia is hyperthermia. This happens when the water is too hot. Swimming for long periods of time in high temperatures doesn't allow the body to properly cool itself. When this occurs, side effects can include nausea, light headedness, dehydration or heat stroke. If you're planning on high-intensity swimming, cooler water under 82 degrees is needed.
Play It Safe
While you probably won't be taking a thermometer with you on your next trip swimming, there are ways to stay safe. Enter the water slowly to test it instead of diving in. If you feel nauseous or lightheaded, take a break to cool off. And bring plenty of drinking water. Off-season water temperatures can be dangerous, and even if you're on a boat and not planning on getting into the water, accidents can occur. So bring warm clothing with you to decrease the effects of cold shock or hypothermia in case of such accidental exposure. Don't forget: Just because it's warm outside, doesn't mean the water is warm too.