When should I use heat vs. cold?

Physiotherapist in Mississauga use thermotherapy is to alter tissue temperature in a targeted region over time for the purpose of inducing a desired biological response. The majority of heat and cold therapies are designed to deliver the thermal therapy to a target tissue volume with minimal impact on intervening or surrounding tissues.  Cryotherapy and thermotherapy are useful adjuncts for the treatment of musculoskeletal injuries and soft tissue injuries. Using ice or heat as a therapeutic intervention decreases pain in joint and muscle as well as soft tissues and they have opposite effects on tissue metabolism, blood flow, inflammation, edema and connective tissue extensibility.

Heat: By increasing the temperature of the skin / soft tissue, the blood flow increases by vasodilatation. The metabolic rate and the tissue extensibility will also increase. Heat increases oxygen uptake and accelerates tissue healing, it also increases the activity of destructive enzymes, such as collagenase, and increases the catabolic rate.

Cold: By decreasing the temperature of the skin/soft tissue, the blood flow decreases by vasoconstriction. It will be followed afterwards by a vasodilatation which will prevent against hypoxic damage. The tissue metabolism will decrease just like the neuronal excitability, inflammation, conduction rate and tissue extensibility. At lower joint temperatures certain enzymes are inhibited.

Many of the local physiologic effects of heat and cold have been studied thoroughly. For instance, heat increases skin and joint temperature, improves blood circulation and muscle relaxation and decreases joint stiffness. Cold will numb the pain, decrease swelling, constrict blood vessels and block nerve impulses to the joint. 

Deep heating is thought to lessen nerve sensitivity, increase blood flow, increase tissue metabolism, decrease muscle spindle sensitivity to stretch, cause muscle relaxation, and increase flexibility. Heat stimulates the cutaneous thermo receptors that are connected to the cutaneous blood vessels, causing the release of bradykinin which relaxes the smooth muscle walls resulting in vasodilation. Muscle relaxation occurs as a result of a decreased firing rate of the gamma efferents, thus lowering the threshold of the muscle spindles and increasing afferent activity. There is also a decrease in firing of the alpha motorneuron to the extrafusal muscle fibre, resulting in muscle relaxation and decrease in muscle tone. 

A very important note that needs to be made is that thermotherapy is safe for people with a normal skin sensation. When a patient has problems with thermal sensitivity, it could be dangerous. They cannot feel if they are being burned due to the application. If you have any questions about how heat ro cold therapy could help your condition, or if you would like to visit our Mississauga physio office, please contact us.