Dogs engage in various types of exercise. This may include structured training, such as for obedience, as well as participation in competitive events such as fly ball and agility. This may also include routine exercise such as running, walking, and swimming. Because exercise is stressful and can disrupt a dog's gastrointestinal tract function, it is important to consider when and how much to feed an exercising dog. The timing of the meal is especially important as it may decrease the stress on the animal.
Exercise can impact gastrointestinal tract function even when the activity is short and the animal is not performing at maximum intensity. Blood flow to the intestines decreases during exercise as blood flow increases to the skeletal muscle, heart, and lungs. This allows for the animal’s body to focus on exercise and not on the uptake of nutrients from the intestinal tract. Intestinal motility (movement) is delayed, causing the stomach to empty and gastric secretions to slow. This decreased rate of digestion leaves the undigested food sitting in the animal’s gastrointestinal tract, which can lead to discomfort, cramping, and bloating.
Timing of feeding
If a dog is given a meal prior to exercise, it can impact the dog’s performance. Because of changes in intestinal motility and stress on the animal during exercise, some dogs may vomit when fed before or during exercise. Feeding before exercise also increases the risk of diarrhea. This can be exacerbated by stress caused by the exercise and lead to dehydration. However, if dogs are fasted for six to 16 hours prior to exercise, there is a decreased chance of negative effects on endurance and performance of the dog. Research has shown that blood glucose levels during exercise are better maintained by dogs that are fasted before exercise compared to dogs fed before exercise. Dogs are able to utilize stored energy and nutrients from previous meals to meet the needs of exercise. Dogs can use protein, carbohydrates, or fat for energy during exercise. The goal of feeding an exercising animal is to limit muscle protein breakdown and protein use for energy needs during exercise. When dogs are fed six to 12 hours prior to exercise, they use more carbohydrates and fat than protein for energy, helping to maintain muscle levels.
It is recommended to feed a meal eight to 16 hours prior to exercise, depending on the size of the meal. If an animal is performing intense exercise (prolonged activity of over an hour), the meal should be limited to no more than one-third of the dog’s daily calorie intake and fed four to eight hours before exercise. However, if feeding a meal that contains the entire dog’s daily nutrient needs, it should be fed 10 to 16 hours before exercise.
What to feed
Active dogs should be fed a nutritionally complete diet. A commercial diet with 30 percent protein and 20 percent fat may be ideal for dogs that perform structured exercise such as regular walks or runs, competing in agility and obedience events, and hunting. Dogs on a diet with high protein and fat will be primed to utilize fat for energy during exercise. It is critical that exercising dogs have access to fresh water at all times. This prevents dehydration and has no negative effects on performance. It is also beneficial to feed smaller meals so as not to overwhelm a dog’s gastrointestinal tract. Feeding at least two meals per day to adult exercising dogs is recommended. A small meal the night before or at least four to six hours prior to a performance event or a long run will prevent a reduction in performance compared to feeding right before exercise. When dogs are fed post-exercise, the nutrients in the diet can replenish amino acids depleted by muscle breakdown during exercise. It can also replenish body stores of carbohydrates in the form of glycogen. This can be beneficial to build skeletal muscle and improve recovery post-exercise.
There are feeding guidelines pet owners should consider when feeding exercising dogs. First, avoid sudden changes in diet. Dietary changes along with exercise add stress to the dog and can cause diarrhea, which then increases the animal's stress and can lead to dehydration. Instead, the diet should be changed gradually over five to seven days. In addition, any increase in feed intake should be done gradually. While energy needs increase for increased activity, the amount of exercise and intake should be increased slowly when an animal begins training.
One of the most important factors to improve performance of an exercising dog is improved training. When training improves, the performance of less active dogs improves. Increased training improves the animal's conditioning, decreases stress, and improves its ability to utilize nutrients. On the other hand, sudden changes in activity level can increase stress, diarrhea, and dehydration. Proper training and nutrition are key to improved performance.
Lisa Karr-Lilienthal, Ph.D. - University of Nebraska-Lincoln