The heat does the following 5 things:
- Enhances vasodilatation* so that more blood is delivered to the muscles.
- Allows oxygen In the blood to detach from the hemoglobin more easily.**
- Speeds up the breakdown of glucose and fatty acids.
- Makes muscles more elastic, less susceptible to injury.
- Burns fat more easily.
You are changing the construction of your body as you perform these postures. Think of it as a piece of steel. When the steel is hot it becomes soft. When the steel is cool, it is easier to break and does not bend as easily. The heat makes your body more malleable. Warm muscles are more elastic and less susceptible to injury. Warmer temperatures produce a fluid-like stretch that allows greater range of motion. Cold muscles don’t absorb shock or impact as well and aren’t stretched as well so they get injured more readily.
Additionally, the oxygen and blood exchange rate is more rapid so you are getting more oxygen to your tissues, and your heart is more efficient. It is clearing out the valves of the heart chambers. It helps to flush out the arteries. Sweating is important because it takes the majority of the workload off the kidneys and the liver allowing the skin, which is the largest organ of the body, to excrete toxins. It exfoliates the skin by ridding the dead skin cells, so your skin will become clearer.
The capillaries that weave around the muscles respond to the heat by dilating. This brings more oxygen to the muscles and helps in the removal of waste products such as carbon dioxide and lactic acid.
* When blood passes through warm muscles oxygen releases more easily from the hemoglobin. Blood passing through cold muscles releases less oxygen.
** Warm muscles burn fat more easily than cold ones. Fat is released during stress. The stress of intense exercise causes a deluge of fatty acids into the blood stream. If you exercise with cold muscles, the muscles cannot use the fatty acids, and the fatty acids end up in places where they aren’t wanted, such as the lining of the arteries.
NOTE: Muscles aren’t the only beneficiaries of heat. Higher temperatures improve the function of the nervous system, meaning that messages are carried more rapidly to and from the brain and spinal cord.