Cooling vest for overweight Bullmastiff

Your vet is right to flag this — a Bullmastiff carrying extra weight is at serious risk in the heat. Obesity reduces a dog's ability to regulate body temperature, and Bullmastiffs are already a brachycephalic breed with a compromised airway, which makes heat dissipation even harder. Cooling vests work through evaporative cooling — you soak them, wring them out, and the slow evaporation draws heat away from the dog's body. They work best in drier conditions; in high humidity they're less effective but still provide some relief through the cool water itself. To point you to the right vest: what's your Bullmastiff's rough weight, what climate or situation are you dealing with — garden, walks, car trips? And how much activity does he do in warm weather?

That context is really helpful. At 62kg with a brachycephalic airway and obesity-related heat risk, you need a vest that offers serious coverage — not a lightweight wrap that only cools a strip across the back. You also need something durable and well-fitted for a broad, deep-chested dog. Can I ask — has he been measured across the chest girth and back length? Bullmastiffs often sit between sizes on cooling vests and getting the fit right matters a lot for coverage and comfort.

At 62kg and typical Bullmastiff build, he'll almost certainly be an XL, but measure his chest girth — just behind the front legs — before ordering. The vest I'd recommend for him is the Ruffwear Swamp Cooler. It's specifically designed for large working dogs, covers the full torso including the belly panel which matters a lot for a heavy dog radiating heat from their underside, and it uses a three-layer evaporative fabric that holds water well and releases it slowly. It's robust, adjustable for deep chests, and it genuinely performs — this isn't a fashion vest. Soak it in cold water for a few minutes before use, wring it out so it's damp not dripping, and re-wet every 20 to 30 minutes in warm conditions. Given what your vet has said, I'd also pair this with strict shade access and fresh water on every outing, even in the garden.

It's reasonably straightforward — it goes over the head and fastens with two chest buckles, so there's no wrestling with legs. The fit is adjustable at both buckle points which helps with his barrel chest. Most dogs tolerate it well once they've worn it two or three times, especially because the cool damp feeling is actually pleasant for them in heat. If he's particularly wriggly, getting him used to it indoors first before you need it urgently is worth doing. One more thing: keep a close eye on him even with the vest on. Pale gums, excessive drooling, or sudden lethargy mean you stop and cool him down immediately — vest or no vest, at his weight the margin for error is smaller than for a fit dog.

Good plan. Measure first, order once — it's worth that extra ten minutes. The Ruffwear Swamp Cooler in XL should serve him well through UK summers and any warm spells. Combined with your vet's guidance and sensible scheduling of outings to cooler parts of the day, you're doing the right things for him. Hope the weight loss journey goes well too — every kilogram he loses will genuinely reduce his heat risk.