A new burst counting method based on a subject invariant characteristic demonstrates the limits of the actual automatic based methods. The exponential behaviour of the counted bursts in function of a variable threshold highlights a scaling property of the muscle sympathetic nerve activity. From experimental single unit recording results, we deduce the exponential-type (gamma) distribution of instantaneous spiking frequency within multi-unit recordings. We show that integrated muscle sympathetic nerve discharges must be gamma distributed with parameters proportional to the number of neurons in the recording pool and to the integration window width.