The other drawback of swimming that researchers have discovered is that, while swimming is great for overall fitness, it is not a very effective tool for weight loss. The reasons for this are not entirely understood. Here are some theories:
* Because water cools the body so much, it is thought that the bodies of swimmers might aim to maintain a layer of fat under the skin for insulation.
* Some researchers believe that being surrounded by cold water for a period of time may increase the appetite, causing swimmers to eat more once they get out of the water.
* Another theory states that people who are successful swimmers may also be genetically disposed to having a higher body fat content, since this leads to increased buoyancy and a rounder shape will offer less resistance in the water.
* Swimming fast requires a high output of energy, which burns glycogen instead of fat. Prolonged exercise at a lower intensity is better for fat burning.
* It is believed that the body's metabolism increases at higher body temperatures. Since the body is cooled while swimming, this could reduce the metabolism and the subsequent amount of food energy burnt by the swimmer.