When a dog pants, it generally pants at a particular frequency. This study explains that that frequency is practical, and further, that “The impracticality of panting at other frequencies is shown by calculation.” The study is:
“Mechanical Aspects of Panting in Dogs,” Eugene C. Crawford Jr., Journal of Applied Physiology, vol. 17, no. 2, March 1962, pp. 249-251.
The authors report:
Apparently healthy, unanesthetized dogs weighing 12.3 ± 1.8 kg were caused to pant by the warming effect of incandescent lamps. Panting frequency was recorded and found to be 5.33 ± 0.7 cycles/sec. The natural frequency of the respiratory system of each of the animals was then determined, the mean being 5.28 ± 0.3 cycles/sec. The increased effectiveness of panting at the resonant frequency of the respiratory system is discussed in terms of respiratory impedance and maximum volume flow with least effort. The impracticality of panting at other frequencies is shown by calculation.