The Effects of Heat on Fascia

Muscles relax with the application of moderate heat. This muscle relaxation causes the fascia encasing the muscle to become more elastic. The fascia is a type of thin connective tissue that holds the muscles of the body together. Relaxing this fascia, along with the muscles, reduces stress tension and relieves pain. Heat can be applied to muscles and fascia using simple home remedies.

Metabolic Process

• Heat inspires change in the body at the microscopic level. These changes affect the amount of glycolytic acid and ATP produced; two biochemical elements needed for energy. A study published by The Journal of Physiology in 1972 found that the application of heat on a muscle causes normal energy-producing metabolic processes to slow down, meaning less energy is made and more used up. Because of this delay, the corresponding muscle has less endurance and relaxes, thereby relaxing the fascia surrounding it.

Layers of Fascia

• There are two layers of fascia that lie below the skin and wrap around a muscle. The Superficial layer is the closest to the skin. It is thin and highly elastic so it can keep up with the movement of the skin outside and the muscle inside. Deep fascia is a tough, flexible connective tissue that keeps the integrity of the muscle intact and reduces friction between individual muscles, so they can move freely. These two layers respond to heat in a similar fashion, but the consistency of the fibers varies depending on the layer. When heat is applied, these layers of fascia become more flexible and the natural sliding function they perform becomes more fluid.

From Gel to Liquid and Back Again

• Fascia has a complex collagen fiber structure that can shape-shift in response to outside stimuli. In its resting state, fascia has a gel-like solid consistency, but when heat is applied it transforms from a gel to a more liquid-like texture, becoming more elastic and giving the muscles room to breathe. When the fascia is in a heated state it is called "sol." When the muscle cools again, the fascia reverts back to its natural gel-like state.

Reasons to Apply Heat

• Constant muscle tension, malnutrition, injury or disease all have adverse affects on fascia. When the fascia is aggravated or injured it can bunch up, much like a blanket bunches together. Applying heat and pressure to the affected area will bring the fascia to a liquid state and reduce tension. This is the principle behind myofascial physical therapies that use manual pressure and heat to treat a patient.

  Chronic muscle tension can block the flow of nutrient-rich fluids to the fascia, making it dry and hard. Again, when heat is applied and the fascia becomes liquid, it opens up the flow of fluid to the fascia and muscles.