Lethargy in dogs is a condition where a dog is less animated than usual or their activity level is decreased from normal day-to-day function. It is characterized by a lack of energy and enthusiasm, and it can be a sign of an underlying health issue. Lethargy can sometimes be described as extreme tiredness, although it isn’t quite the same. A lethargic dog is not interested in his/her normal day-to-day life and is either unable or unwilling to get up out of bed very often. Signs of lethargy vary considerably from one dog to another and include the following:

• Tiredness or sleepiness
• Lack of interest in usual activities
• Reduced activity level
• Weakness or inability to move well
• Stiffness and pain when moving

Lethargy can be a sign of many different conditions in dogs, and its what veterinarians refer to as a nonspecific sign, meaning that something is affecting your dog’s normal behavior, but that it does not amount to a diagnosis. Some conditions that can have dog lethargy as a common symptom include:

• Infection
• Disease
• Viral or bacterial infection
• Reaction to a vaccine
• The dog’s mental state
• Effects of medication
• Heart disease
• Liver disease
• Tumors/cancer
• Pain
• Trauma
• Chronic or acute diarrhea
• Snake bite
• Hypothyroidism and other hormone problems
• Anemia
• Poisoning (for example from eating foods that are toxic to dogs, like garlic, leeks, or onions)
• Anal gland problems

If your dog is lethargic with no other symptoms, she may simply have overtired herself on a long walk or playing at the dog park, or she might be too hot but not yet at the point of heatstroke. However, if she has other symptoms, they can help you pinpoint the cause of the lethargy. Its important to know your dog’s normal activity level so you can tell when they’re becoming lethargic. If you’re not sure, it’s better to err on the side of taking your dog to the vet so, if there is a serious problem, you get it taken care of as quickly as possible.