The benefits of heat therapy in horses
Heat therapy is a diverse and beneficial modality
What is heat therapy?
The application of heat can be used for a multitude of benefits in horses. Heat has analgesic properties, meaning it can help reduce pain. Heat also increases circulation to the area it is applied. Heat is especially beneficial in athletes as it enhances muscle elasticity through increasing circulation and the temperature within the muscle tissue. Increasing muscle elasticity can help prevent muscle injuries1. Some studies have shown that heat applied to muscles immediately pre-competition increases the ability of tissue collagen to elongate under load, or stretch when working.
One important note: Heat felt in horse tendons should not be ignored or thought of as beneficial. Heat in tendons is a sign of damage to the tendon structure and should be seen by a veterinarian. Applying heat to tendons has not been show in studies to benefit performance or athletic ability.
Types of heat
There are many sources of heat such as infrared lamps/solariums, heat pads, thermal wands, rugs lined with ceramic or other heat reflecting material, and many other modalities which induce superficial heating. Superficial heating works on tissues to approximate 2cm deep. Superficial heating is affordable and easy to use on horses.
Deep heating tissues to a depth of 3cm or more can be done with ultrasound. Deep heating is beneficial for arthritis, but it not commonly available to most people due to the cost and technical use of the machines which typically require a veterinarian, physiotherapist or rehabilitation specialist to use.
Benefits of heat therapy
Local vasodilation, or increase in circulation increases by four to five times that of resting level in temperatures up to 42°C. This increase in blood flow is only sustained for 30 minutes, then reaches a plateau and eventually declines. This increase in local circulation helps promote healing in sub-acute and chronic inflammation.
Heat therapy helps reduce pain through producing a sedative effect in the sensory nerve endings. Heat helps the muscles relax and release, which can be beneficial for tense, stiff muscles or knots. Additionally, heat reduces muscles spasms, which can be causing pain. Relaxed muscles have an increased range of motion over cold, stiff muscles1.
Heat increases and improves the elasticity of muscles and tissues in the heated area, which can aid in stretching after heat application. Heat can be used to warm up tissues before activity, which is commonly seen with horse solariums/infrared lights. Stretching your horse should only occur when the horse’s muscles are warm, either from exercise or heat application.
Heat increases the metabolic activity in the cells of the skin and superficial underlying tissues. Specifically, heat increases the oxygen uptake of tissues in the area which accelerates tissue healing. Heat helps promote white blood cell migration into the area to aid with healing.
Heat therapy is great at providing relief of joint stiffness following injury. It can also help relieve joint stiffness and ease pain in arthritic joints of older horses. Heat can help horses increase their range of motion in their joints from stiffness.
While heat in beneficial for a range of uses, there are some situations in which heat should NOT be used2:
• On tissues producing heat due to acute injury
• On tendons after exercise
• On any metal implants, pins or plating
• On new fractures
• On recent bleeding or bruising in an area of injury
• On malignant (cancerous) disease
• On swollen areas
• On post-operative surgical areas
How do you use heat therapy?
Ideally heat therapy should not be used for more than 30 minutes. Ideal heating time ranges from 15 to 30 minutes and can be done 2 or 3 times daily. Temperatures between 40 and 45°C show the most benefit for healing, pain relief and comfort for the animal. Temperatures above 45°C are not recommended in horses as it can result in tissue damage and pain in the horse2. Horses should not be left unattended while undergoing heat therapy. It is recommended that you check any hot packs, heating pads or other heat sources against your skin first to ensure the temperature it not too warm and will not burn or hurt your horse. You should also check periodically under the heating device for redness and irritation and remove if you see any signs of this.
1. Bromiley, M. (2007) ‘Heat’ in Equine Injury, Therapy and Rehabilitation. Blackwell Publishing
2. Tomlinson, J. and Goldberg, M.E. (2018) ‘Thermotherapy’ in Physical Rehabilitation for Veterinary Technicians and Nurses. Ed by Mary Ellen Goldberg. Wiley Blackwell Publishing.
