Effects of a pulsed electromagnetic field (PEMF) therapy blanket on salivary cortisol and behavior in horses

Domesticated horses are frequently exposed to high-stress environments due to their housing, travel, and use in competitions. Pulsed electromagnetic field (PEMF) therapy has been posited as a potential approach for alleviating horse stress, with research supporting PEMF for treatment of human stress related to mental health conditions. This study sought to determine if a commercial PEMF blanket affects horse salivary cortisol concentrations, relaxation behaviors, or stress behaviors. Horses (n=36) were randomly assigned to two treatment groups and one control group. The Pr3 group received treatment at 1-6 Hz and the Pr7 group received treatment at 10-30 Hz. Both treatments were set at 5 millitesla (mT). The control (C) group was exposed to two conditions: wearing the blanket at 0 Hz (CB) and not wearing a blanket (CNB). Horses were exposed to 30 min treatments every other day for 15 days, with salivary cortisol sampling and behavior observations on days 1, 9, and 15. Salivary cortisol concentrations displayed some variability, but there were no significant decreases in salivary cortisol from pre to post when comparing conditions. Horses exhibited more relaxation behaviors under the CB condition when compared to the CNB condition ( p = 0.031), but there were no significant differences when comparing controls and treatments. There were no significant differences for stress behaviors in any of the comparisons. Although the PEMF blanket treatment did not appear to reduce stress behaviors or salivary cortisol in our study, future research with longer treatment periods, alternate treatment protocols, and additional sampling times is recommended. • There are few guidelines on using pulsed electromagnetic field therapy with horses. • Horse relaxation behavior increased with a PEMF blanket at 0 Hz versus no blanket. • Use of a PEMF blanket at 1-6 Hz or 10-30 Hz did not alter horse behavior. • Eight 30-minute PEMF treatments over 15-days did not reduce equine stress.