Notes from Daryl Reynolds lecture “Cryotherapy”

Cryotherapy
Cryotherapy is the use of cooling as a means of treating injuries
1. Body tissues will be either stretched or impacted (heal strike) causing microscopic blood vessels to be torn or damaged, during prolonged running activities
2. The extent of bleeding will depend on the vascularity of the tissues involved, and may be increased if injured during high intensity activities such as exercise, due to the increased blood flow to the working muscles
3. The first response will be to limit microscopic blood loss from the capillaries (vessels), attenuated by the body through (vasoconstriction), so preventing further blood leaking into the surrounding tissues
4. This causes cells to be starved of nourishment from lack of blood supply, with tissue death following
5. These dying cells stimulate the release of histamine causing the blood vessels to dilate, thereby bringing increased blood supply and extra nutrients to help repair and rebuild the damaged tissues.
6. The histamine response induces an increased but slower and more viscous blood supply, where the capillary walls become much more permeable and quantities of protein and inflammatory substances are pushed or leaked from the blood into the damaged tissue area causing extracellular swelling.

Treatment
By applying ice or cooling immediately after a so called injury involving damage to soft tissues, the level of swelling and amount of blood allowed to leak out may be substantially reduced.

One should follow the typical R I C E routine

Ice application: When applying ice, never do so directly onto the skin as this may result in ice burns to the skin. Wrap the ice in a damp not wet cloth, a dry cloth restricts heat transfer from the tissue to the ice, and too wet causes burning.

Recommended application times vary depending on the researcher, however the accepted standard currently used is 10 min Max. Any longer than 10 minutes and a reflex reaction occurs, where blood flow is increased to the tissues, causing excessive swelling. (Hunting reflex) Ice also has a second analgesic effect, of pain reduction.

One should avoid application of heat within the first 24 to72 hours (acute phase), the actual time limit depending on the severity of tissue damage, as 1, this will cause extra and intracellular swelling with cellular lyses and second, the body is self heating.

If tolerance to ice is poor, it may be substituted with a cryotherapy device such as a cryocuff or cold pack typically kept in the fridge, as these are more tolerable to those with a high pain response. Water baths are an option also.
Remember, the principle is to draw heat from the body, resulting in temperature variance. The extremes of temperature are not as important as the temperature variance, although not all research agrees.

Contraindications for cryotherapy include sensitivity to cold, diabetes, application to chest area, high blood pressure, nerve damage.