A preliminary study on the impacts of exercise intensity and duration on gastrointestinal temperature and odor detection performance of dogs

Working dogs are often deployed in physically demanding environments such as search and rescue or military operations. It is widely assumed that prolonged or intense exercise reduces their ability to detect odors—but the physiological drivers behind this decline have remained uncertain. To investigate this, we used a controlled setup in which dogs performed a go/no-go odor detection task on a motorized olfacto-treadmill. This setup allowed us to manipulate exercise intensity and duration while measuring olfactory performance alongside physiological responses including heart rate and gastrointestinal temperature. In Experiment 1, dogs exercised at a constant pace—either walking (low intensity) or trotting (moderate intensity)—for 33 minutes. Olfactory performance remained stable while walking but declined sharply after 21 minutes when exercising at a moderate intensity. Gastrointestinal temperature change emerged as a strong predictor under these conditions. To test whether this effect was causal, Experiment 2 introduced a mid-session switch in pace. This decoupled gastrointestinal temperature from exercise intensity and duration. Performance declined during moderate intensity exercise and remained low even after switching to low intensity exercise. Dogs switching from walking to trotting showed the steepest performance drop. In this more diagnostic design, exercise intensity and duration—not gastrointestinal temperature—were the strongest predictors of olfactory sensitivity. Heart rate was not predictive of olfactory sensitivity in either experiment. These findings provide evidence that olfactory performance declines with physical exertion, but reveal that the underlying cause is not elevated heart rate or body temperature. Rather, the intensity and duration of activity were the primary drivers. This layered disentanglement underscores the value of controlled designs in resolving physiological mechanisms and suggests that simple, non-invasive metrics like pace and duration may offer practical tools for managing detection performance in working dogs. • Dogs completed a go/no go odor task while simultaneously exercising on a treadmill using an olfacto-treadmill setup. • Olfactory performance remains stable during a walk pace, but declines as exercise duration increases at a trot pace. • Dogs had the steepest drop in olfactory performance when switching to the trot pace after beginning a testing session at a walk pace. • Exercise intensity and exercise duration are the main predictors of olfactory decline in our experimental setup, with heart rate and gastrointestinal temperature having minimal influence on predicting olfactory performance.