Injury and Ice; The Hunting Response in the context of Cryotherapy

by Kris Wahl

What is Cryotherapy?

Cryotherapy is a treatment that involves the use of cold temperatures to help reduce pain, inflammation, and to promote the body's innate healing processes.

What is the Hunting Response?

The Hunting Response is the body’s physiological reaction to alternating cold and warm temperatures.

During Cryotherapy, the Hunting Response is exaggerated, making it especially useful for reducing swelling, improving blood circulation, and expediting recovery from injury.

Here is how it works:

When cold is applied to the body, blood vessels constrict (a process aptly referred to as vasoconstriction), in an effort to limit circulation to preserve the body’s core temperature. This vasoconstriction temporarily decreases local circulation, which in turn helps decrease inflammation. 

After a brief period of cold exposure and the removal of that cold stimuli, the body reacts by increasing blood flow in a rebound effect. This dilation of capillaries is called vasodilation. This “warming phase” floods the tissue with fresh blood, rich in oxygen and nutrients. With the influx of these fresh metabolic materials, metabolic waste is flushed from the area. This sets the injury site up to receive a fresh supply of nutrients, aiding in a faster recovery.

This cycle of vasoconstriction and vasodilation will continue as long as the cold stimuli is applied and removed. However, as with most things, moderation is always recommended.

During Cryotherapy, it is important to avoid prolonged or excessively cold applications, as this can lead to tissue damage. While there will always be a variance from body to body, generally, a standard medical ice pack with a buffer (like a towel) between the pack and your skin can be safely applied to an injury site for about 15 minutes. This should be enough time to stimulate the first phase of the Hunting Response. Ice is then removed for an additional 15 minutes so that the Hunting Response can complete the warming phase of it's cycle. In just one or two cycles, recovery time can be significantly impacted.

Understanding the mechanics of the Hunting Response in the context of Cryotherapy can help inform our choices when injuries occur, leading to improved outcomes.