Winter Riding …

Is it Good for the Horse?

There is a secret society of riders, ones who relish donning thick jackets and another pair of wool socks.  Who love the whish-whish of snow pantsand the static snap of polarfleece.  And just who are they??  They are the riders who are joined in their love of the beauty and inspiration of, gasp, winter.  They thrive in the crisp air, love being out under the startling blue skies and to gallop through the thick blanket of last night's snowfall.

But, when it comes to exercising horses in the real cold, they, and many others of us, may wonder about its potential for harm.  The pervasiveness of asthma among the human population, and the growing number of adults who are now finding that exercising in the winter can trigger troublesome shortness of breath and wheezing have riders wondering if equines might be suffering the same future.

The good news is that horses, so far, have shown a consistent ability to tolerate low to high levels of exercise in very cold temperatures.  The somewhat bad news is that all the data on providing a comprehensive picture of what specifically a horse experiences in such conditions are not yet completed, and that any hidden dangers are yet to be determined. 

To make cold-weather exercise safe for a horse, some evidence may be indicating that it is “as simple as building his tolerance for it,” says Mike Davis, DVM, PhD, Professor and Endowed Chair, Exercise Physiology, at Oklahoma State University's Center for Veterinary Health Sciences in Stillwater.  Some experts believe that horses acclimate to cold-air exercise by experiencing a gradual exercise in intensity -- in fact, the adaptation process is nothing more than a cycle of exposure (increased exercise to cause more rapid respiration) followed by a period of rest.   The process is often paralleled to aerobic conditioning, the well-known cycle in which the muscle and other soft tissue are regularly challenged and then rested, then challenged again. In both scenarios, this pattern is repeated until a desired level of fitness is achieved.  Davis cautioned that, “In my opinion, it is reasonable to expect the airway to adapt on some level, but no work has been published on this topic”; in other words, little proof exists at this time.

But a rider's own response to tolerating cold air while exercising can provide insight during any given cold-weather ride -- in other words, the rider can infer from his own comfort level the comfort level of his horse.  For example, winter (human) athletes can experience coughing or breathlessness, the latter an indication of the narrowing of the bronchi to help stand guard against the unwanted drying effects of winter air.  Behavior to suggest that similar things are happening to the horse (repeated coughing, unexpected breathlessness, gagging or excessive mouthing) should then be considered warning signs to back off the level of exercise.

The useful parallels continue:  Studies have shown that during cold weather, human athletes can experience what is termed "ski asthma," the exercise-induced asthmatic condition that crops up immediately post-exertion in chilly air and is primarily marked by wheezing.   These symptoms are also accompanied by an increase in mucus production, a tell-tale scarring of the windpipe (found upon examination) and as Davis characterizes it, a "twitchiness of the windpipe to snap shut more aggressively when faced with cold air." 

These same signs under the same conditions are also seen in horses, dogs and even lab rats.  Says Davis, "It looks like horses can have 'ski asthma,’" but he again cautions that no studies have been performed on horses to determine this.  Yet, strangely, this cluster of symptoms -- which can also appear with exposure to diesel exhaust and ozone -- has also shown so far to have no effect on the performances of dogs and lab rats, and to have shown no permanent degradation of the airway or its capacity to perform.  

However, Davis cautioned that acclimating is essential.  A horse, for example, shipping from a warm southern state to a northern state during winter months needs to be treated conservatively so it can adjust without incident.  "A horse accustomed to 70- to 80-degree weather will get his airways hammered the first time they experience 20- to 25-degree weather," he noted.  It is key, therefore, in order to avoid undue harm, that airways are allowed to recover, usually requiring a period of 48 to 72 hours before exercising the horse moderately again in cold temperatures, and "after about a month [of progressively more demanding exercise], the horse should be fine."  Davis's findings are based on his preliminary studies of race horses, both at the track and in the laboratory, as well as of sled dogs of the north.

So, here are some things to keep in mind for the winter-riding enthusiast:

•  Beginning at around 40 degrees Fahrenheit and below, cold air will begin to "tweak" and affect the airways.
•  A horse is acclimated to the temperature at which he has been working, and will continue to need to be acclimated to any further influx of colder temperatures.
•  Coughing by the horse at the start of exercise is not considered abnormal.  But, should the horse cough four or more times a minute, it is a sign of airway irritation.
•  Studies are now including immunology, as there some speculation that cold-air exercise may temporarily lower the response of the immune system (in both horses and humans).
•  As noted above, during the acclimating period, the airways need to recover between each episode of exertion in cold air.  Recovery period is considered to be two to three days.
•  At this time, no temperature has been deemed "too cold" for equine exercise, and age of the horse seems to not be a factor.
•  Findings at this point remain inconclusive concerning the effects of cold air and exercise.  Riders and trainers should err on the side of caution, work with their vets, and stay informed on the latest information on this topic.