When was the last time you were up close and personal with a piece of exercise equipment or
a pair of running shoes? Does the thought of going for a 5 mile run make you realize that you
have spent way too much time on the couch this past winter? If your horse could talk it would
probably share your sentiments in regard to jumping right into a long exercise outing when it
has spent the past several months lounging near the round bale, getting a hay belly, and
becoming unfit. Some people think that conditioning a horse is a mystical process. Keeping in
mind that a horse has much more in common with us human beings than with a motorcycle or
four-wheeler, will help to remove a lot of the mystery from the conditioning process.
Why should we be concerned about our horses’ fitness levels as we beginning riding them
after their long winter off? Horses, like humans, can experience many adverse effects of
exercising too long and/or too hard without proper conditioning. Also similar to humans,
horses have positive adaptations to exercise that will increase their performance over time.
There are several exertional myopathies or muscle diseases caused by exertion that can occur
in the horse. They are usually produced in one of two ways. They made be a result of
exercise following a period of inactivity during which the horse is maintained on a grain diet.
The other main cause of exertional myopathies is inadequate conditioning of an unfit horse
prior to prolonged strenuous exercise. These exertion related muscle diseases are often
classified into three diseases: azoturia, typing up, and endurance related myopathies.
Azoturia, also known as Monday Morning Disease or Blackwater Disease, has been
recognized as an exertional myopathy since the days when draft horses were doing the farm
work. Farmers used to complain that their workhorses would have performance problems
upon returning to the fields after a day or two of rest. This is because the horses’ grain rations
were not decreased when the horses were rested for a day or two. Azoturia means nitrogen in
the urine, which aptly describes what occurs as a result of excessive break down of muscle
tissue in the horse. When horses are kept on high carbohydrate diets their muscles
accumulate large amounts of stored energy (starch) in the form of glycogen as their activity
level is reduced. When the horse goes back to work these large stores of glycogen are broken
down for energy. In the process of converting glycogen to energy, lactic acid is produced in
the muscle. Excessive quantities of lactic acid wreak havoc with the horse’s muscles. The
vascular system cannot flush the lactic acid out of the muscle fast enough. Therefore, the high
concentration of lactic acid degrades the muscle cells and myoglobin is released from the
muscle cells into the system. The horse’s kidneys are not designed to handle myoglobin
clearance, thus an excessive strain is placed on the kidneys that may result in their failure. All
of this damage can occur as soon as 15 minutes after the horse returns to work. It may also
occur up to one hour after the horse has begun to exercise. It should be noted that the
exercise does not necessarily have to be vigorous either.
Symptoms of azoturia are numerous and may be difficult to distinguish from severe colic. An
affected horse may exhibit profuse sweating, and have an increased heart rate and/or
respiratory rate. In addition, a stilted gait, muscular stiffness and spasms, and difficulty
Conditioning Your Horse for Athletic Events
Debra J. Hagstrom, MS, Equine Extension Specialist, University of Illinois
Conditioning Your Horse for Athletic Events, page 2 of 8
controlling the hindquarters are also seen. Furthermore, a hunched appearance may be
evident. Finally, if the horse’s urine is red-brown, or black (often compared to coffee or cocacola)
that is a sure indication that muscle damage is occurring and myoglobin is being cleared
from the body via urination. It also suggests that kidney damage is occurring. Muscle atrophy
(wasting) is the irreversible end result. If your horse exhibits any of these symptoms it is
imperative that the horse not be moved. Any further activity will only compound the damage
already occurring to the horse’s muscles. A horse exhibiting any of the symptoms of azoturia
requires immediate veterinary attention. For those who have a horse that has had an episode
of azoturia, be aware that the first attack seems to predispose a horse to subsequent attacks.
Tying-up (post-exertional myopathy) is a mild form of azoturia that is more commonplace. This
muscle disease usually occurs at the beginning of exercise or when the horse is cooled down
after a vigorous workout. Symptoms of tying up include the horse showing reluctance to move,
its muscles being hard to palpation, and the horse exhibiting a short, stiff, stilted stride. The
affected horse may or may not sweat excessively and may or may not have discolored urine.
Similar to azoturia, the horse is not to be moved during a tying-up episode and immediate
veterinary attention is vital.
Endurance related myopathy is similar to tying-up, however, it occurs in adequately
conditioned horses that have been ridden for long distances. Affected horses may be severely
dehydrated with salt and electrolyte imbalances.
Synchronous diaphragmatic flutter (SDF), commonly known as Thumps, is sometimes seen in
less physically fit horses that become exhausted from exercise, or in fit horses that are
exercised in hot, humid weather to which they are not accustomed. Thumps is a synchronous
contraction of the diaphragm with the horse’s heartbeat. Visually, a twitching or convulsive
motion in the flank area occurs simultaneously with the atrial contraction of the heart. If their
diaphragm is not contracting properly then they are less efficient in their breathing. Thus SDF
affects the oxygen intake of the horse. Horses that are low calcium or potassium
concentrations in the body are more susceptible to SDF.
Horses are susceptible to heat exhaustion and heat stroke just like people. Either condition is
by and large observed in poorly conditioned horses that are overexerted in hot, humid weather.
Heat exhaustion and heat stroke may occur with light work or heavy work. Symptoms are
numerous and varied. A horse experiencing distress due to overheating may display
weakness, rapid breathing, heavy sweating or no sweating at all (anhidrosis), and/or elevated
pulse and temperature. Additionally, an affected horse may have muscular tremors or may
refuse to continue working. Furthermore, dehydration is common and lack of appetite and
depression may also be seen. Often the horse’s temperature will rise dangerously high to
106°-110°F for a prolonged time period. The horse may collapse hours after exercising. In
worse case scenarios a horse may slip into a coma and die. Immediate veterinary attention is
critical. The first priority is to decrease the body temperature of the horse as quickly as
possible. This is most promptly accomplished by giving the horse an ice or cold-water bath.
Conditioning Your Horse for Athletic Events, page 3 of 8
This recommendation is contrary to popularity held beliefs. However, when horses are in such
a state of distress that their body temperature is 106°-110°F as a result of heat
stroke/exhaustion, the most crucial treatment is anything to reduce the horse’s temperature.
When children have alarmingly high temperatures for an extended time period, they are often
put in ice or cold-water baths to help rapidly decrease their temperature. The same theory
applies to horses. Horse competing in the Atlanta Olympic games were cooled down with ice
and cold-water baths and that was done based on the advice of the attending veterinarians.
Other methods of cooling a horse down include putting the horse in shade and using fans.
When a horse reaches such a state of exhaustion and hyperthermia fluid therapy via a
nasogastric tube is usually essential also, thus veterinary attention is required.
The positive adaptations to exercise that a horse acquires can significantly increase its
performance. These adaptations include improvements within the cardiovascular system,
metabolic mechanisms, aerobic system as well as the temperature regulatory system.
Cardiovascular adaptations occur as soon as two to three weeks into a conditioning program
for your horse. At this early date there is an increase in blood volume, by increasing the
number of red blood cells as well as increasing the volume of plasma. This results in an
increase in oxygen carrying capacity to the horse’s working muscles. As with most muscles in
the body, the horse’s heart size increases with exercise and conditioning, though it does not
happen as quickly as the increases in blood volume. This increase in heart size allows for an
increase in maximum cardiac output during exercise. A third positive cardiovascular
adaptation resulting from adequate conditioning of a horse occurs between the third and sixth
month of exercise. At this time there begins to be an increase in the number of small blood
vessels within the skeletal muscle. This improves the efficiency of oxygen extraction from the
blood, thus providing more oxygen to the muscle tissues. Furthermore, as a horse’s level of
fitness improves there will be a reduction in heart rate during submaximal exercise (trot or slow
canter). Along with that, the recovery heart rate (return to resting heart rate) will be faster in
well-conditioned horses.
Metabolic function improvements as a result of conditioning have important implications. First,
there is more efficient utilization of fuel substrates. During submaximal work an increase in the
amount of fat utilized for energy production is seen. There is a subsequent decrease in the
quantities of blood glucose and muscle glycogen used as energy sources known as "glycogen
sparring”. As a result a horse is able to sustain a higher work rate during prolonged exercise
without the build-up of lactic acid. This allows the horse to exercise longer before becoming
fatigued.
Aerobic adaptations generate an increase in VO2max, which is the maximum rate at which the
body can consume oxygen. Within eight to twelve weeks of initiating a conditioning program, a
horse’s system is increasing the oxidative capacity of its muscles. This is accomplished by a
boost in the number and size of the cell structures that are responsible for aerobic metabolism.
There is a complimentary increase in the quantity of enzymes involved in aerobic metabolism.
Conditioning Your Horse for Athletic Events, page 4 of 8
These aerobic adaptations coupled with the cardiovascular adaptations can increase a horse’s
VO2max by up to 30% which results in a marked improvement in overall work capacity, meaning
a horse is able to sustain higher speeds for longer periods.
Lastly, the thermoregulatory system also shows improvement with conditioning of the horse.
Metabolic heat presents a potential problem for horses. Physical activity requires an
enormous amount of energy; therefore, a huge amount of heat energy is released during
exercise. When stored energy is converted to work it is only 20-25% efficient, which means
that 75-80% of stored chemical energy is converted to heat within the muscle cell. This heat
energy causes a rise in body temperature. Without a means to lose this heat, the horse’s body
temperature would reach dangerously high levels after only a short period of exercise.
Seventy percent of this heat is removed by the evaporative cooling of sweating. Unfit horses
lose more electrolytes and protein through sweating than fit horses. Their sweat typically is
very white, lathery, and sticky with a strong odor, whereas the sweat of well-conditioned
horses is clean and clear, and more watery. This allows them to retain more essential
electrolytes and proteins needed during exercise.
So, how do you go about developing a conditioning program for your horse? The first thing
you need to do is evaluate the current condition of your horse. Heart rate (pulse) is the best
individual guide to condition response and status. Recovery heart rate is a universal means to
assess fitness. It is important to monitor your horses resting heart rate as well. Most horses
will have a resting heart rate less than 42 beats per minute (bpm). Similar to humans, horses
in a high level of fitness will have a lower resting heart rate, maybe even as low as 26 bpm.
While doing moderate work, a horse’s pulse ranges from 75 to 105 bpm; however, it may
increase to over 200 bpm during heavy work. The horse’s heart rate should recover to below
60 bpm within ten to fifteen minutes of rest. Horses in poor condition recover in 30 to 45
minutes. If, after ten to fifteen minutes, your horse’s pulse recovers to between 44 and 52
bpm, the horse can tolerate an increase in exercise. However, if your horse’s pulse is greater
than 72 bpm after the recovery period, then your horse was worked too hard.
One should also be aware of how the horse’s resting pulse rate corresponds to its respiratory
rate. A horse’s normal resting respiratory rate ranges between 8 and 16 breaths per minute.
The heart rate:respiratory rate ratio should be 3:1 or 2:1. If the heart rate:respiratory rate is 1:1
the horse is in a stressed condition and should stop exercising immediately.
Once you have determined your horse’s normal resting heart rate, then what? Start your
conditioning program early. Remember that approximately one month is required to achieve
significant aerobic and cardiovascular improvements. Start with lower speed and longer
distance exercise. Exercise the horse three to five days per week. Keep in mind though that it
is important to give your horse a day off every third or fourth day. If you exercise your horse
everyday without a day off you could create a situation where you horse becomes chronically
fatigued, which may result in fatigue-related lameness or depress your horse’s immunity,
making him more susceptible to illness. For the optimum conditioning benefit your horse
Conditioning Your Horse for Athletic Events, page 5 of 8
should exercise at a level that puts his working heart rate in the target zone of 135 to 155 bpm,
which is about 60%-80% of his maximum heart rate. As your horse’s fitness improves, as
evident by the lowering of his recovery heart rate, his level of exercise may be increased. This
can be accomplished by increasing one of three aspects of the horse’s exercise program.
Either the duration, the intensity (speed), or the distance can be increased; however, it is
important that only one of these aspects is increased at one time to prevent the horse from
being overworked in the next phase of his conditioning.
An additional training concept to improve a horse’s condition is interval training. By gradually
overloading, interval training can effectively increase the amount of work a horse can perform
prior to fatigue. Interval training is accomplished by having the horse do short, intense
exercise periods during which the heart rate increases to 180 to 200 bpm. These intense
intervals should not exceed 2 minutes in duration. After the intense phase the horse should be
slowed to a jog until its heart rate returns to nearly 100 bpm. When a horse’s heart rate is 180
to 200 bpm he is doing anaerobic work, meaning his muscles are working too hard and fast to
rely solely on oxygen in the process of burning fuel. Anaerobic work is necessary in the
process of conditioning a horse. It will increase the amount of work a horse can do prior to
fatigue. Making the horse gallop on the flat or long trot up a hill can increase intensity. Keep
in mind that conditioning is exercise specific. In other words, the type of conditioning must
emulate the competitive event in which the horse will later be required to participate.
Every time you ride your horse you should perform a pre-ride check. This is the time to check
your horse’s resting heart rate. Keep in mind that some horses may have an increase in heart
rate if they anticipate being ridden. Therefore, taking resting heart should be done before the
horse is brought to the location where it is typically saddled. If the resting heart rate is higher
than normal it could indicate one of several things: an adrenalin rush (e.g. startled by
something, or has just been disciplined), pain, or illness. Prior to riding you should also
determine your horse’s resting respiratory rate realizing that the environmental temperature
and humidity may affect this parameter. Additionally, as you are grooming your horse prior to
saddling do a visual inspection for any injury, soreness or lameness, paying particular attention
to back or loin soreness.
Another extremely important step to include in your horses conditioning program is an
adequate warm-up period. Warming your horse up is key to minimizing the chance of exercise
related injuries. The benefits of warm-up period are three-fold. The horse’s body temperature
is raised and blood flow is increased to working muscles. As a result, the muscles and
tendons are loosened which increases the range of motion and helps avoid pulling or tearing of
tendons and ligaments. In addition, the muscles are warmed up allowing them to
accommodate harder work by more adequately relaxing and contracting. Finally, a moderate
warm-up will better prepare the horse to dissipate heat during intense exercise. A successful
warm-up routine consists of walking the horse for five minutes and then trotting for five minutes
before moving on to more demanding work.
Conditioning Your Horse for Athletic Events, page 6 of 8
Just as important as the warm-up is the cool down. This is light work that will gradually bring
the horse back to a resting state. Generally this is accomplished by simply reversing the order
of the warm-up (five minutes of trotting followed by five minutes of walking). The importance of
the cool-down period is that the slower work helps the blood remove lactic acid from the
horse’s muscles. This is necessary to minimize stiffness and soreness in the horse day after
it’s workout. Remember that the horse’s recovery heart rate must also be determined ten to
fifteen minutes post-ride. Furthermore, the horse should be again visually evaluated for injury,
soreness or lameness.
During training, it is vital to be able to recognize dehydration in your horse. Water makes up
more that 65% of a horse’s mass. Water is an essential requirement for proper muscle and
metabolic function, as well as thermoregulation in the working horse. As previous mentioned
sweating is responsible for approximately 70% of the heat dissipation in horses. The major
component of sweat is water. Thus water loss in the exercising horse may be great. Typically
a horse cannot be identified as dehydrated until it has lost at least four gallons of water (about
32 lbs of body weight). A horse can die after losing about nine gallons of water (about 72 lbs
of body weight). When the weather is very hot fluid loss can approach four gallons per hour.
These data make the importance of recognizing dehydration obvious.
There are two simple ways to recognize dehydration in a horse. First is the blood capillary
refill test. To determine a horse’s hydration level using this method, press your thumb against
the gum of the horse’s upper lip until it turns white. Once the gum has turned white remove
your thumb and record how long it takes for pink color to return to that area. A horse is
normally hydrated if blood returns to that area within two seconds. Varying levels of
dehydration are present if it takes longer than two seconds for blood to return to that area. If it
takes close to 10 seconds for blood to return then the horse is severely dehydrated and needs
immediate fluid therapy administered by a veterinarian. In addition to the 10 second capillary
refill time the horse’s gums may appear bluish in color and its membranes may be dry.
The second common test used to evaluate dehydration is the skin pinch test. Pinch a fold of
skin on the horse’s neck near the shoulder and release it. A normally hydrated horse’s skin
will flatten immediately. In a slightly dehydrated horse, its skin will take up to five seconds to
flatten, whereas a moderately dehydrated horse may need as much as 10 seconds for it skin
to flatten. If a horse is severely dehydrated the skin doesn’t flatten. Furthermore, there will
mostly likely be no saliva production and the horse’s eyes will appear sunken.
There are several strategies to help prevent dehydration in the exercising horse. One of the
easiest ways is to feed your horse a significant amount of grass hay. For every 2.2 lbs of dry
hay a horse eats it will consume up to one gallon of water. Within the large intestine, the fiber
in the hay or other forages traps this water. This reserve of water (and electrolytes) is then
available for absorption during exercise. As a result this helps offset the fluid and electrolyte
losses in sweat while the horse is working. Thus high fiber diets are beneficial for prolonged
Conditioning Your Horse for Athletic Events, page 7 of 8
exercise in horses. Additionally, horses should have free choice salt available to them on a
regular basis, as large quantities of salt are lost when horses sweats.
Conditioning your horse for hot and humid weather will help prevent dehydration. Exercise
that causes the body temperature to increase by 2°F in 70°F weather will cause almost a 4°F
increase in hotter weather. Furthermore, high humidity can decrease evaporative cooling via
sweating by as much as ninety percent. This means that performing the same amount of work
in a humid climate requires the horse to sweat up to ninety percent more than in a less humid
climate which translates into a ninety percent increase in water requirements. It takes at least
ten days for a horse to begin to acclimate to higher humidity and increased temperatures. Be
sure to take the weather into consideration during your training. In addition, pace your horse
during his workout. Allow him to rest and catch his breath in between harder more strenuous
maneuvers.
Hosing your horse down with water at the end of its workout can be very helpful in preventing
dehydration. It provides evaporative cooling similar to sweating, helping cool the horse down
in addition to helping him maintain hydration via less sweating. If your horse will be doing
prolonged exercise (e.g., long distance riding or trail riding) allow your horse to drink at every
opportunity. Sweating uses water faster than drinking replaces it. With significant salt loss via
sweating, the horse’s thirst response often is suppressed so his amount of thirst may not be an
accurate indicator of hydration. Also, allow your horse to graze or eat forage at every
opportunity. Fresh grass will provide a small amount of water for the horse and dry forage will
increase a horse’s desire and need to drink.
Identifying the fatigued horse is also essential in a successful conditioning program. A change
in sensory state or attitude is often a sign of fatigue. If a horse is usually very alert and aware,
traveling with a higher head carriage, he is most likely experiencing some degree of fatigue if
he is hanging his head and appearing lethargic. As a horse becomes fatigued he is more
prone to soft tissue injury (strained muscles and pulled ligaments). Furthermore, his stride
may be less controlled, resulting in interference during his stride, or stumbling and tripping.
When the quality and consistency of movement is compromised the horse is fatigued. The
end result of fatigue is often lameness or at a minimum significant soreness. Determining your
horse’s recovery heart rate will tell you if your horse has been pushed to a state of fatigue. As
stated earlier, if its recovery heart rate is greater than 72 bpm after ten to fifteen minutes of
rest, the horse has been overexerted and is experiencing fatigue.
When it comes to maintaining condition in your horse it is useful to know that fundamental
fitness remains with horses for six to eight weeks. Moreover, horses that have been trained up
to a level of competition and given an extensive layoff, return to fitness much faster than
horses that have never reached that competitive level of fitness. This is a critical point to keep
in mind if you are conditioning more than one horse. Depending on the fitness history of the
horses you may not be able to use the same conditioning program.
Conditioning Your Horse for Athletic Events, page 8 of 8
In summary, you should start your conditioning program early. Starting early allows you to go
avoiding fatigue and injury in your horse. Conduct pre-ride checks, beginning with determining
the horse’s resting heart rate. Always begin workouts with a warm-up (five minutes at a walk
and five minutes at a trot) to heat and loosen the muscles, tendons and ligaments which will
allow them to function better during more demanding work. Move carefully to interval training
and don’t let it exceed more than 2 minutes time periods. Recognize dehydration and fatigue.
Complete each workout with a cool-down (five minutes of trotting and five minutes of walking).
Finish by conducting a post-ride check including determining recovery heart rate. Temper the
duration and intensity of workouts during hot humid weather until your horse has been
conditioned to the change (at least 10 days). Finally, keep in mind that when it comes to
conditioning, horses are more similar to humans than Hondas.
