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Friday, March 6, 2015

Conditioning part 1-How the Horse's body responds

Conditioning is vitally important to all horses in all disciplines from the elite three day eventer to the weekend trail rider.  Every horse needs to be properly conditioned for the task they perform to prevent injuries and other detrimental effects such as tying-up.  There are multiple reasons to condition your horse.  Conditioning helps the horse by increasing cardiovascular fitness, strengthening support structures, increasing neuromuscular coordination, and improving thermoregulation (the body’s ability to control temperature).  All of these things are very important to keep you and your horse safe and healthy throughout any activity. 

Cardiovascular fitness encompasses many things.  First, the heart is a muscle that through proper conditioning and over time, it’s strength and pumping capacity will increase.  As pumping capacity increases the amount of beats necessary to supply properly oxygenated blood to the body decreases (i.e. your heart rate decreases).  This is why heart rate is such a great way to monitor fitness.  You can do this with a heart rate monitor or by simply learning to take heart rate 5, 10, and 15 minutes after exercise.  Overtime as your horse reaches a better fitness state, the amount of time it takes for the heart rate to return to normal and the peak heart rate your horse experiences should decrease.  As your horse gains fitness it will be able to more efficiently oxygenate the system thereby increasing the length of time in aerobic metabolism. Aerobic metabolism, during exercise, is the most efficient way to supply energy for muscle contraction.  Aerobic metabolism requires oxygen though so once the body is pushed beyond its ability to oxygenate fully you enter into anaerobic metabolism. Those of you that hit the gym or in other ways exercise on a regular basis know well what lactic acid is.  Horses just like humans produce lactic acid when they push past their body’s limit to oxygenate entering into anaerobic metabolism. Increased cardiovascular fitness leads to decreased anaerobic metabolism and lactic acid production.  Lactic acid buildup leads to fatigue while exercising and muscle soreness.  Significant fatigue while exercising increases a horse’s chance of injury.  So you can see why cardiovascular fitness is so important.

Strengthening of support structures takes more time than cardiovascular fitness.  It is vitally important that a horse’s muscles, tendons, and ligaments are up to the task at hand.  If you put a completely unfit horse back into work it can take 4-6 months for all the support structures to completely strengthen depending on the intensity of the horse’s job.  This is why a horse is brought back very slowly following a serious tendon/ligament injury.  First the injured tendon needs to slowly strengthen back to full capacity to avoid being reinjured.  Secondly an injured horse has usually been on stall rest so all support structures have weakened and need time to adapt to exercise again.  When starting into a conditioning program it is important to carefully monitor your horse’s limbs on a regular basis so heat or swelling can be picked up on immediately and attended to properly.  When a horse is pushed to perform more than their support structures are ready for, they can end up compensating, leading to lameness, soreness, and possible significant injury. 

Increased thermoregulation is tied into cardiovascular fitness.  Within 1-2 weeks of starting a regular conditioning program the horse’s volume of plasma, red blood cells, and hemoglobin increases.  Plasma is the liquid (non-cellular) part of the blood.  Also over a period of months the amount of capillaries present in the muscle increases.  These increases help better oxygenate muscles and cool the body.  It is a common misconception that a fitter horse starts sweating later and sweats less.  In contrast the fitter horse has a more efficient thermoregulation leading them to sweat sooner and stay cooler.  A fit horse is able to do this due to increased blood volume and capillary system carrying blood to the skin where heat is evaporated off while also still efficiently supplying muscles.  Effective sweating starting earlier helps dissipate heat before the thermoregulatory system is overloaded i.e. overheating occurs.  Aerobic metabolism, while the best way to get energy for muscle contraction, is very inefficient and produces large amounts of heat.  This significant amount of heat production during exercise explains why efficient cooling is so important.

Now we understand the different systems and how they are enhanced by a conditioning program.  There are many ways to approach starting a conditioning program depending on your horse’s job.  The basics of this will be covered in our next blog post.  Please stay tuned for more information and tips on how to successfully and safely get your horse fit.  In the meantime Dr. Oehling would be happy to answer any questions you may have about conditioning and how it applies to your specific horse and situation.