Table 2.

Integrated MSNA and action potential indices at baseline and during maximal end-inspiratory apnea

	Baseline	Apnea
Integrated MSNA
Burst frequency, bursts/min	15 ± 8	48 ± 7*
Burst incidence, bursts/100 heartbeats	28 ± 16	77 ± 9*
Normalized burst amplitude, AU	24 ± 6	58 ± 9*
Total MSNA, AU	366 ± 220	2,745 ± 478*
AP indices
AP frequency, spikes/min	174 ± 151	1,083 ± 487*
AP incidence, spikes/100 heartbeats	325 ± 293	1,766 ± 829*
APs/burst, spikes/burst	11 ± 4	24 ± 12*

Values are means ± SD. MSNA, muscle sympathetic nerve activity; AU, arbitrary units; AP, action potential.

^*Significantly different from baseline, P ≤ 0.01.