The sun is out,the air is warm and you want to go swimming. It is still technically winter so the water will still be cold. Be sue to test the water temperature before you plunge in. Cold water can shock your body and make your blood pressure and heart rate go up. You might accidentally open your mouth to yell and accidentally breathe in some water. Cold water can also slow your muscles, making it hard to swim. Be sure to follow the water safety rules and never swim alone.