A canine model to evaluate the effect of exercise intensity and duration on olfactory detection limits: The Running Nose Provisionally Accepted

Edgar Aviles^1* Joerg Schultz² Michele N. Maughan, Ph.D.³ Jenna D. Gadberry⁴ Dana M. DiPasquale⁵ Brian Farr⁶ Eric Best⁷ Dakota R. Discepolo⁸ Patricia Buckley⁴ Erin B. Perry⁹ Debra L. Zoran¹⁰ Nathaniel J. Hall^1*

• ¹Texas Tech University, United States
• ²Tier Wohl Team GbR, Germany
• ³Excet (United States), United States
• ⁴U.S. Army Combat Capabilities Development Command Chemical Biological Center, United States
• ⁵Valiant Harbor, United States
• ⁶USA MEDCOM, United States
• ⁷University at Albany, United States
• ⁸United States Army, United States
• ⁹Southern Illinois University Carbondale, United States
• ¹⁰Texas A and M University, United States

Detection canines serve critical roles to support the military, homeland security and border protection. Within the military, some explosive detection tasks are physically demanding for dogs, and prior research suggests this can lead to a reduction in olfactory detection sensitivity. To further evaluate the effect of exercise intensity on olfactory sensitivity, we developed a novel olfactory paradigm that allowed us to measure olfactory detection thresholds while dogs exercised on a treadmill at two different exercise intensities. Dogs showed a substantial decrement in olfactory detection for low odor concentrations under greater exercise intensity. Specifically, dogs hit rate for the lowest concentration dropped from 0.87 ± 0.04 when walking at low intensity to below 0.45 ± 0.06 when trotting at moderate intensity. This decline had an interaction with the duration of the session in moderate intensity exercise, whereby dogs performed near 100% detection in the first 10 min of the 8km/h session, but showed 0% detection after 20 min. Interestingly, hit rates for high odor concentrations were relatively stable at both low (1 ± 0.00) and moderate (0.91 ± 0.04) exercise intensities. The paradigm and apparatus developed here may be useful to help further understand causes of operationally relevant olfactory detection threshold decline.