thumps

The primary cause of the condition generally known as “Thumps” is athletic stress, in other words, excessive exercise that the dog is not quite conditioned to handle.

This causes a temporary electrolyte imbalance and low blood calcium levels that increases the PH of the blood, this in turn increases the irritability of the Phrenic Nerve which is the nerve that controls the contractions of the diaphragm.

This nerve passes over the heart on its way to the diaphragm and is further stimulated by the electrical activity of the heart, causing rhythmic contraction of the diaphragm in rhythm with the thumping of the heart as the dog attempts to recover from the run.

Treatment and prevention require maintaining good hydration and adequate electrolyte and calcium levels. The addition of small quantities of Magnesium to the diet can also help for those dogs prone to this condition.