Blood pressure drops in dieting dogs

For years, Dr. Tony Carr has suspected that obese dogs have higher blood pressure than dogs with normal weights. It’s a logical theory since hypertension is a prevalent concern for most overweight humans, but still, no one had ever proven that link in spontaneously obese dogs.

Based on findings from a canine weight loss study, Carr’s hunch appears to be right: WCVM researchers noticed a decline in blood pressure measurements of the project’s dogs as they lost weight.

“The changes in blood pressure measurements weren’t huge: it was a difference of 20 or 30 millimetres of mercury (mmHg). I don’t think these changes would mean anything to a normal, healthy dog. But in dogs that have other problems such as heart or kidney disease, this could have a significant impact,” says Carr, a WCVM internist who has a special interest in blood pressure.

All of the dogs enrolled in the Novartis-funded study eventually lost considerable weight after their owners put them on a calorie-restricted diet and began regularly exercising them. Researchers chose the study’s dogs — all patients at the WCVM’s Small Animal Clinic — for two reasons: the animals were calm enough to take accurate blood pressure measurements, and they were markedly obese (at least 20 per cent overweight with a body condition score of eight or nine).

Our goal was to lose 20 per cent of their body weight or to achieve a body condition score of five (normal to slightly overweight). For most of these dogs, that was a tremendous loss,” says Carr.

At the beginning of the study, researchers gave each dog a physical examination, estimate body condition scores, then conducted a long list of laboratory tests — including assays to rule out other obesity-causing problems like hypothyroidism and Cushing’s disease.

While researchers took regular blood pressure measurements from dogs throughout the study, all other tests were only repeated at the project’s end. A comparison of those tests helped researchers determine whether the dogs’ reduced size affected other health parameters besides blood pressure.

Besides helping researchers find answers to important health questions, the study’s dogs enjoyed a healthier lifestyle. In most cases, dog owners saw positive results after two to three weeks, reporting that their slimmed down pets seem to be more playful and have more energy.

Read “Fat Cats and Portly Pups” to learn more about managing your pets’ weight.

Reprinted with permission from Vet Topics, news publication for the Western College of Veterinary Medicine’s Companion Animal Health Fund. Visit www.cahf.usask.ca to sign up for Vet Topics’ e-newsletter.