We all know dogs require daily exercise to thrive. But in the rush to provide our canine companions with a good cardio workout, we may be overlooking another equally important need: The need for dogs to sniff!

Sniffing is central to a dog’s experience of his environment. Consider the daily dog walk. As we put one foot in front of the other alongside our best friends, our human eyes scan the scene in front of us to make sense of our surroundings. But for our dogs, it’s their nose that knows—and it knows more than we can begin to imagine. Just sniffing a patch of grass, for instance, can reveal detailed information about other dogs who have passed through the area, including their gender, age, diet, how recently they stopped by, and much more.

Think of sniffing as the canine equivalent of a mental workout. We have our work and hobbies, problems and puzzles, and Shakespeare and physics to keep our minds occupied and sharp. Dogs have an infinite world of smells to catalog and interpret. A good dog walk then, is a balance of physical and mental exercise. And that means taking time to smell the roses—or at least allowing your dog to do so. Give your dog plenty of time to sniff what interests him, especially on short potty walks where physical exercise isn’t a focus.

Let your dog initiate sniff breaks on longer walks, too. If you worry about your dog getting enough physical activity, try adding some running to your walks, or games of fetch or tug during walks or at home. Also keep in mind that mental exercise can be quite taxing all on its own (just think how tired we humans can feel after a day of hard thinking work). So next time you put on your tennis shoes and reach for the leash, try rephrasing that age-old question to “Wanna go for a sniff?”