Cryotherapy is the therapeutic application of cold.  This noninvasive modality provides a rush of crisp, almost cyclonic airflow which aides in the management of injuries, painful conditions, and lower levels of inflammation and oxidative stress.  A steady stream of pressurized CO2 at -108ºF with 52 bar (754 psi) quickly reduces the horse’s skin surface temperature in the treated area to 39ºF, the optimal temperature necessary to produce five key physiological processes collectively known as the “cryotherapeutic response.”

Within just 30 seconds, this powerful response significantly increases blood flow to the treated area, enhancing the delivery of oxygen, healing proteins, and essential nutrients for accelerated recovery.  At the same time, lymph vessels contract and remove excess fluid, toxins, and waste.

ANALGESIC RESPONSE

Extreme cold has an analgesic effect, reducing nerve conduction velocity. The extreme cold of high pressure on the treated area cools the nociceptors (nerve endings in the horse’s skin responsible for detecting pain).  This slows down the speed at which the nerves conduct pulses.  As a result, fewer pain signals from the affected area are sent to the brain, thus less pain is experienced. 

In addition, the reduction in inflammation and swelling, along with the later increase in blood circulation, helps relieve muscle tightness and discomfort. 

ANTI–INFLAMMATORY RESPONSE

When tissues are injured by bacteria, trauma, toxins, or any other cause, blood flow to the area increases and damaged cells release chemicals from the white blood cells to fight the invaders.  This causes redness and swelling in the injured area creating inflammation.  Warmth is often caused by circulating inflammation.  High blood flow and vasodilator immune factors increase the amount of fluids, proteins, and white blood cells entering the damaged site.  This creates pressure, which causes fluid to exit extracellular spaces, leading to swelling and pain. 

Cryotherapy is known to create an anti–inflammatory response and reduced swelling in several ways: 

  • Vascular permeability and blood flow to the affected area decreases due to vasoconstriction.  This prevents more fluid, white blood cells, and other chemicals from entering the damaged tissues relieving the pressure and reducing swelling. 
  • Production of certain pro–inflammation cytokines is decreased.
  • Production of anti–inflammatory cytokines is increased. 
  • The extreme cold also triggers the lymphatic system to flush out waste and toxins that have built up in the tissue. 
VASOMOTOR RESPONSE

RAPIDPERIPHERALVASOCONSTRICTION

Extreme cold triggers vasoconstriction. This is a narrowing of the blood vessels by the constriction of smooth muscle cells.  Blood is then redirected to vital organs, where it attains heightened oxygen and nutrient density.  The decrease in blood flow reduces swelling and inflammation in the cooled tissues and prevents further build–up of excess fluids. 

Post–treatment, vasodilation occurs to warm the cooled tissues back up to normal skin temperature.  Smooth muscle relaxes and blood vessels expand, increasing in diameter.  Blood enters the treated area at an increased volume.  Oxygen, collagen, and other essential nutrients are delivered to tissues for repair and recovery, while toxins and other waste substances are removed.  Muscle elasticity and flexibility are improved, reducing tightness and increasing mobility. 

RAPID PERIPHERAL VASODILATION

To restore homeostasis, the horse’s body begins to warm the treated area back to its normal temperature, causing blood to return to the skin‘s surface.

Rapid vasodilation occurs when blood vessels, including arterioles and capillaries, expand, allowing for increased blood flow.This process floods the treated area with “supercharged” blood, delivering up to four times the amount of fresh oxygen and essential nutrients needed for healing. This enhanced circulation accelerates and improves the natural healing process, promoting faster and more efficient recovery.

MYORELAXANT RESPONSE

As a result of reduced nerve velocity, muscle fibers relax, leading to decreased tension and stiffness. This relaxation helps alleviate muscle spasms, cramping, and general soreness, providing relief from pain and discomfort.

LYMPHATIC RESPONSE

The lymphatic system is a horse’s natural detox system.  It is a network of vessels that runs through the whole body and removes any waste fluid, bacteria, and microbes from cells. The system is passive and relies on the contraction of muscles instead of the heart for the lymph fluid to be pumped around the vessels.  Poor lymphatic drainage can lead to Lymphangitis, a condition that causes swollen limbs (usually hind limbs).  Cryotherapy reduces the risk of developing lymphangitis by increasing lymphatic circulation.  The extreme cold triggers the lymph vessels to contract, draining the injured area of any toxins, waste and excess fluid. 

Increased lymphatic drainage leads to:

  • Reduction in inflammation and swelling.
  • Pain relief.
  • Improved immunity.  White blood cells are triggered to attack and destroy any unwanted substance in the fluid.  This helps to fight or prevent infection. 
  • Quicker and more efficient recovery from common horse injuries and conditions.