Effects on humans and horses
Most cold therapy is applied for no more than 20 to 30 minutes at a time, with an hour between treatments. The majority of
cold-therapy studies have been done in humans, which is proble-matic in that horses do not seem to respond to cold and its
application in the same manner as do humans. For example, reflex vasodilatation was not recognized in horses after 30 minutes
of cold therapy (4 degrees Celsius).
Photo 5: This horse is wearing an ice boot that allows either ice cubes, crushed ice or ice packs to be placed in packets
inside the wrap. The neoprene boot is then applied to the desired area of the leg, and compression is achieved because of
the elasticity and stretch of the wrap. The combination of cold and compression produces significant tendon and ligament cooling.
Sonya Nightingale, a physiotherapist at the Highworth Physiotherapy Clinic in Ireland, has investigated the comparative effects
of topical cooling agents in horses and sees the large body of human cold therapy data as potentially confusing when applied
"Most research into the use of cold has been done in the human field in applications over muscle tissue", she writes. "In
the horse, cold therapy usually is used in the lower limb over tendon and bone and over considerably hairier skin, so the
results of human research are therefore probably not transferable to the equine field and may result in inappropriate treatment".
Photo 6: (ProChoice boot) This shows the interior of an ice boot with the various compartments that can be filled with ice.
Along with vasoconstriction, cold therapy also promotes anti-inflammatory effects by inhibiting histamine, neutrophil activation,
collagenase activity and synovial leukocytes. Cold also decreases tissue metabolism — as much as 50 percent when temperature
is dropped by 10 degrees. Slower metabolism reduces the cells' demands for oxygen and can reduce tissue damage in the immediate
Cold has been shown to reduce muscle spasms by decreasing the activity of muscle fibers. Reduced spasm can reduce cell trauma
and death and keep muscle damage to a minimum following strenuous exercise or competition. Cold also decreases nerve-conduction
velocity, making tissue less sensitive; it is thought to be the biggest factor in the analgesic effect of cold therapy. A
combination of these factors — reduced inflammation, reduced swelling, reduction of heat and a lessening of pain — all make
cold therapy a valuable asset in equine athletic management.
Cold therapy should be started as soon as possible after exercise and certainly following trauma. Most studies show that cryotherapy
started on the first day of trauma is associated with a quicker resolution of problems and return to full function than when
cold treatment was started two days after injury.
In sound, healthy horses, postexercise cold therapy helps in the "cooling out" process and may reduce any potential tendon
stiffness or swelling, so it, too, should be initiated as soon as possible after work.
Research done by Drs. Birch, Wilson and Goodship of the Royal Veterinary College in the United Kingdom has shown that as little
as seven minutes of strenuous exercise can produce tendon and ligament temperatures of 113 degrees. Cooling these areas as
soon as possible after work can reduce the potential damage that this elevated temperature may cause.