Various embodiments intermittently deliver a sympathetic stimulus, including deliver a sequence of stress-inducing pacing pulses adapted to increase sympathetic tone during the stress-inducing pacing. The stress-inducing pacing results in a parasympathetic reflex after the sequence of stress-inducing pacing. The embodiment further delivers neural stimulation to elicit a parasympathetic response or a sympathetic response in a coordinated manner with respect to the sequence of stress-inducing pacing pulses. The neural stimulation is timed to elicit the parasympathetic response after the sequence of stress-inducing pacing pulses and concurrent with at least a portion of the parasympathetic reflex to the sequence of stress-inducing pacing to enhance a parasympathetic effect of the parasympathetic reflex, or to elicit the sympathetic response during the sequence of stress-inducing pulses to provide a larger sympathetic stimulus, resulting in an enhanced parasympathetic reflex in response to the large sympathetic stimulus.