Effect of Fasting on Equine Heart Rate

A surprising result was found when researchers looked at heart rate in horses that had been denied access to feed. Horses fasted for 24 hours had slower heart rates, though the stress of not having access to food was predicted to increase the rate.

The horse’s sympathetic nervous system normally increases heart rate while slowing digestion, and its parasympathetic nervous system normally decreases heart rate while enhancing digestion. At rest, most horses are dominated by the pattern of a slower heart rate and continuous digestion.

Healthy Thoroughbred horses in this study, which was conducted at the University of California, Davis, were divided into two groups, one of which was fasted for 24 hours while the other group (control) was fed normally. Then the groups were switched so that each horse participated in each treatment. Significantly slower heart rates were found when horses were in the fasting group.