Why are senior and overweight dogs more at risk in hot weather?

Fat tissue insulates the body, which is useful in cold weather but works against a dog trying to shed heat in summer, since that same insulation traps warmth close to the body core. A dog carrying even a moderate amount of extra weight, commonly seen in dogs 10 to 20 percent over an ideal weight, can struggle noticeably more with heat than a lean dog of the same breed and size.

Older dogs often have reduced cardiovascular efficiency, meaning the heart and lungs cannot move blood and air as effectively to support rapid panting, and many seniors also carry some degree of joint stiffness that makes them less able to move to shade quickly or adjust their position for comfort. Underlying conditions common in older dogs, such as reduced heart or airway function, compound the risk further.

Shorten walks, favor early morning or evening timing, and check in more often for signs of struggling during any outdoor activity with a senior or overweight dog. Keeping a dog at a healthy weight through the year, alongside a vet-guided weight loss plan where needed, is one of the more effective long-term ways to reduce heat risk in summer.

A short bench rest halfway through a walk, or splitting one walk into two brief outings, suits many older or heavier dogs better than a single continuous route in warm weather. Keeping water accessible throughout the day, not just during a walk, also helps these dogs manage heat more comfortably.