Sympathetic and vascular effects of short-term passive smoke exposure in healthy nonsmokers.
BACKGROUND
The physiological effects of cigarette smoking have been widely studied; however, little is known about the effects of acute exposure to sidestream smoke (passive smoking). We examined the effects of sidestream smoke on muscle sympathetic nerve activity (MSNA) and forearm vascular resistance (FVR) at rest and during stressful stimuli, including the cold pressor test (CPT), sustained handgrip (SHG), and mental stress (MS).


RESULTS
In 17 healthy nonsmokers, blood pressure (BP), heart rate (HR), forearm blood flow (venous occlusion plethysmography), FVR, and MSNA (obtained through direct intraneural recordings) were measured before and during inhalation of sidestream smoke in one session (n = 16) and before and during vehicle (air) inhalation in another session (n = 17) on a separate day. The order of sessions was randomized between subjects. Responses to CPT, SHG, and MS were measured before and after inhalation of smoke or vehicle (ie, twice during each session). After 15 minutes' exposure to sidestream smoke, plasma nicotine and carboxyhemoglobin levels increased to 0.77 +/- 0.11 ng/mL and 0.36 +/- 0.04% (mean +/- SEM, P < .05), respectively. Sidestream smoke, but not vehicle inhalation, increased resting MSNA from 23 +/- 2 to 28 +/- 2 bursts/min (P < .05). FVR increased with passive smoking, but this increase was not significantly different from the change in FVR with vehicle. Plasma norepinephrine and epinephrine, BP, and HR were not changed significantly by sidestream smoke. The responses of MSNNA, BP, HR, and FVR to the stressful stimuli were not potentiated by sidestream smoke, except for an increased BP response to the CPT (P < .05).


CONCLUSIONS
Acute short-term passive (sidestream) smoke exposure elicits a modest increase in MSNA in healthy non-smokers but does not change HR, BP, or FVR.
Hausberg
M
M
Department of Internal Medicine, Cardiovascular Center, University of Iowa College of Medicine, Iowa City 52242-1081, USA.
Mark
A L
AL
Winniford
M D
MD
Brown
R E
RE
Somers
V K
VK
D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D002248:Carbon Monoxide / Q000097:blood; D004562:Electrocardiography; D005260:Female; D005542:Forearm / Q000098:blood supply; D018737:Hand Strength / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008606:Mental Processes / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000294:innervation; D009538:Nicotine / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D011311:Pressoreceptors / Q000502:physiology; D012016:Reference Values; D013312:Stress, Physiological / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014655:Vascular Resistance / Q000502:physiology*
D014028:Tobacco Smoke Pollution; D009538:Nicotine; D002248:Carbon Monoxide