Exercise Intolerance in Dogs

Exercise intolerance is commonly confused with lethargy, which is defined as an extreme decrease in the willingness to exercise or move.

Exercise intolerance most commonly presents in association with obesity, which has multiple negative impacts on a dog’s health.
Exercise intolerance is also a symptom of other serious medical conditions, such as heart disease, anemia, or diabetes mellitus. Most cases of exercise intolerance require prompt veterinary care. Dogs that collapse suddenly, are severely lethargic, or unable to rise require immediate, emergency veterinary care.

Maintaining a healthy lifestyle, including frequent exercise, reduces the risk of exercise intolerance due to obesity. Regular, year-round use of heartworm prevention is an effective way to prevent exercise intolerance due to heartworm disease. Regular dental cleanings also help minimize the risks for heart disease and subsequent exercise intolerance. Frequent veterinarian visits can help identify other potential causes of exercise intolerance early, improving their prognosis.

Exercise intolerance may be categorized in accordance with the severity of symptoms.

Mild cases may present as an unwillingness to walk or participate in activities. Severe cases of exercise intolerance may result in collapse, pale gums, and cyanosis with exercise. The collapse may be total or only affect the rear legs causing the appearance of poor coordination or balance.

A dog presenting symptoms of exercise intolerance will likely undergo the following diagnostics to determine the underlying cause:

• Physical examination
• Blood test
• Diagnostic imaging
• Urinalysis

Exercise intolerance is a symptom of an underlying medical problem and not a condition in itself. Treatment depends on the underlying condition. Prognosis depends on the underlying cause and varies greatly. In all cases, prompt veterinary treatment increases the probability of a positive outcome.