Keeping Dogs Fit for Life

Keeping dogs in top physical condition probably means more to those who compete at dog shows or field trials than to those with retired champions turned housedogs. In reality, keeping dogs fit for life is as important as it is for humans.

Knowing how much exercise and conditioning a dog needs comes in part from experience. Profes­sional dog show handlers Gabriel and Ivonne Rangel use a treadmill along with free play in an exercise paddock to condition dogs. Marty Knibbs, a professional trainer of English Springer Spaniels, road works dogs from an all-terrain vehicle to give them performance depth.

"Regular moderate exercise provides most of the same benefit to dogs as it ds to humans," says Michael Davis, D.V.M., Ph.D., DACVIM, professor of veterinary physiology at Oklahoma State University. "It tones muscle, lubricates joints and improves heart health. It may also strengthen the immune system.

"One key element in that statement is the term 'moderate,'" he says. "Moderate is the level of exercise that dsn't do harm. Obviously that level of exercise varies from dog to dog and even within an individual dog, depending on fitness and other health issues. Common sense rules — if a dog injures something, that was too much."

Establishing a Benchmark
Before engaging in a conditioning program, one should establish a dog's current physiological limit. "A dog's physiology is designed for endurance so it won't take much time for him to attain the conditioning level needed to participate at the level determined to be the optimal amount of exercise," says Robert Gillette, D.V.M., M.S., director of Auburn University's Veterinary Sports Medicine Program. "At some point the dog's physiological limit will be reached and then it will be time to start setting a new workout distance."

Starting slowly and gradually introducing a dog to the desired workout distance and speed help to lay positive groundwork and increase the chance of success. In other words, "you don't want to intro­duce the dog to too much exercise too soon," Gillette says.

"If exercise is introduced properly, the musculoskeletal system will adapt appropriately." If the goal is to increase a dog's distance endur­ance, trainers should set a new workout distance that is half the last distance increase. "If the last workout was two miles and the dog started showing signs of fatigue at two and a half miles, then the next workout distance should be two and a quarter miles," Gillette says. "Keep in mind it takes four to six workouts for the dog's physiology to adapt and be ready for the next distance increase."

Improving performance requires asking a dog to do something it can't do easily, but in a safe manner, Davis says. "The simplest example is muscle. In order to improve muscle fitness, the muscle must adapt, but first it must be given a reason to adapt and the clearest reason is fatigue. The muscle needs to be shown that the current level of fitness is insufficient for what it is being asked to do. The biochemical processes of fatigue activate the processes that remodel the muscle, making it better at the activity."

A fine line differentiates fatigue that promotes adaptation and fatigue that injures an animal. "There is no substitute for careful observation and thinking," Davis says. "It is impossible to dictate a blanket recipe for training if for no other reason than if the initial steps are successful, the level of exercise that results in just a little bit of fatigue is changing as the dog gets more fit."

Converting Chemical Energy
Understanding what happens physiologically when a dog works is imperative. "During exercise muscle activity is the main internal heat producer," says Gillette. "Of the energy expended by the muscles, 20 to 30 percent is used for work and 70 to 80 percent is released as heat. The heat increases body temperature during exercise. This increase is not detrimental to a conditioned dog. This dog will start panting to address the temperature increase."

Davis elaborates. "At the most basic level, exercise is the conversion of chemical energy to mechanical energy. The actual conversion takes place when the muscle contracts, but long before then a multitude of chemical reactions break down food and convert the chemical energy stored in food to a chemical 'currency' that can be spent by the muscle.

"Ultimately, the majority of energy comes from breaking bonds between two carbon atoms — regardless whether they come from sugar, fat or protein. Once broken, the carbon is waste and must be discarded. In animal cells, this is accomplished by converting the waste to carbon dioxide, a gas that can be easily moved to the lungs and eliminated by simply exhaling."

As exercise continues the body's ability to eliminate carbon dioxide becomes more challenged. "At first the body will expel the extra carbon dioxide by sighing," Gillette says. "Later an increase in respiration, or panting, is needed to address the increasing carbon dioxide production related to work."

An overworked dog runs the risk of heat stress. "Heat is the greatest threat to an exercising dog," Davis says. "Panting and evaporation through the mouth are a dog's primary mechanism for eliminating body heat. Without sweat glands dogs are comparably handicapped at eliminating metabolic heat — the other major byproduct of exercise besides carbon dioxide. As a result, it is expected that a dog's body temperature will increase during exercise. But, keep in mind, dogs can only tolerate a few degrees and only for a short period."

Fundamental to conditioning dogs, and keeping them fit for life, is being aware of signs of stress and quickly taking steps to cool them down. Likewise, it is important to watch dogs carefully when they are training to be sure they are not tiring and thus at risk of suffering an injury. Healthy, well-conditioned dogs should be the goal regardless whether dogs compete at shows or field trials or simply take walks around the neighborhood or play in the backyard.