Whether sniffing for birds, bombs or drugs, chasing Frisbees® or criminal suspects, jogging as a training partner or racing around an agility course, dogs participate in diverse physical activities of varying intensities. Each of these different activities have unique performance requirements that influence an individual canine athlete’s metabolism and energy needs.
Fueling your canine athlete — providing the right amount of energy from the right fuel sources at the right time — is critical to optimal performance. Read on to learn more about how a dog’s body fuels exercise.
Three nutrient categories provide energy
Like people, dogs have energy requirements that must be met to fuel body functions. Energy isn’t one of the major nutrients — those are water, carbohydrates, protein, fat, vitamins and minerals. Yet after water, energy is the second-most critical component of the diet. Why? Because the body needs energy to fuel all of its metabolic reactions.
Bodies will always use food energy to first meet their basic energy demands, such as maintaining tissues and regulating body temperature. Once those needs are met, energy is used for other functions, including movement and physical activity.
All of these energy needs are met by eating food, and are satisfied by three nutrient categories:
Fat, carbohydrates and protein generate different amounts of energy (measured as calories) when metabolized. Dietary fat is the most concentrated energy source, providing more than twice the amount of energy as carbohydrates or protein. Carbohydrates and protein provide about equal amounts of energy. Since additional activity typically requires more energy, knowing about energy density and the differences between nutrients is important to meeting the energy needs of working and sporting dogs.
Call it exercise, physical activity or work — it’s all about muscle metabolism
Physical activity — or call it work or exercise, if you prefer — results from a complex series of muscle contractions. This muscular work requires energy, which is obtained from “burning” dietary fuels. The two primary fuels used by working muscles are glycogen, a storage form of carbohydrates, and free fatty acids, which are produced during the breakdown of fat. Under most conditions, amino acids from protein contribute only small amounts of energy to what’s used during exercise.
A dog’s muscle metabolism is unique compared to other species. Canine muscles consist of fibers capable of using large amounts of oxygen (known as oxidative capacity in exercise physiology circles). The muscles of dogs also have high numbers of mitochondria, which are the “energy powerhouses” of cells. But what makes a canine athlete’s muscles truly unique is that they also include fibers that have high anaerobic (without oxygen) capacity. These muscle fiber types have high levels of enzymes required for glycogen metabolism. As a species, dogs are “built” for both endurance and high-intensity sprints.
Fueling canine muscles during exercise
Energy demands (and other nutrient needs) for canine athletes are determined by exercise intensity, duration and frequency. While the preferred fuel source of dogs’ muscles at rest is fat, exercise intensity causes the source to shift.
At low-intensity exercise, muscle relies on aerobic (with oxygen) metabolism and uses primarily fat (as free fatty acids) for fuel. Interestingly, studies show that dogs burn (oxidize) fat at a higher rate than other species at rest and during exercise, meaning that their muscles are better adapted to using fat as a primary fuel.
During moderate-intensity exercise — which is the category into which most canine athletes fall — energy to working muscles is provided by both fat and carbohydrates, with a very small amount coming from protein.
Finally, high-intensity exercise is fueled through muscle glycogen and glucose stores.
What this means for feeding your athletic dog
When choosing a dog food for your sporting or working dog, you’ll want to consider the type, intensity, duration and frequency of the physical activity that your dog performs. Dogs involved in sports that involve short periods of high-intensity exercise — such as agility, flyball or dock jumping — may not have higher energy requirements than moderately active pet dogs. These dogs can be fed an adult maintenance dog food.
Dogs who participate in endurance activities, such as field trials, hunting and herding, will require more energy given the longer distances that they travel. These athletic dogs benefit from higher proportions of fat in their diet such as those found in performance or high-energy dog foods. Not only will fat deliver more calories to meet a canine athlete’s energy demands, but it can actually “prime” or “metabolically condition” the dog’s metabolism for efficient use of fat for energy.
If you’re wondering if your sporting or working dog’s performance would benefit from a dietary change, talk with your veterinarian first. She or he can help determine if your canine athlete needs a food that provides more energy from fat or carbohydrates and if your dog is getting enough protein.
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