Neural circulatory responses to carbon monoxide in healthy humans

Martin Hausberg, Virend K. Somers

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


The contribution of carbon monoxide (CO) to the acute cardiovascular effects of smoking is not clear. Using a double-blind, randomized, vehicle- controlled study design, we examined the sympathetic and vascular responses to modest increases in carboxyhemoglobin in 10 healthy humans. We measured muscle sympathetic nerve activity (microneurography), forearm blood flow (plethysmography), heart rate, blood pressure, and minute ventilation at baseline and during 60 minutes of CO inhalation (1000 ppm during the first 30 minutes and 100 ppm during the last 30 minutes). The same measurements were made in a vehicle session (room air inhalation) on a separate day. During the first 30 minutes of CO inhalation, carboxyhemoglobin levels increased progressively from 0.2±0.1% to 8.3±0.5% and were maintained at about this level for a further 30 minutes. Forearm vascular resistance did not change with CO but increased slightly with vehicle; the effects of CO on muscle sympathetic nerve activity, forearm blood flow, blood pressure, heart rate, and minute ventilation were not significantly different from the effects of vehicle. Modest increases in carboxyhemoglobin levels equivalent to those resulting from cigarette smoking are unlikely to contribute to the acute sympathetic and hemodynamic effects of smoking in healthy humans.

Original languageEnglish (US)
Pages (from-to)1114-1118
Number of pages5
Issue number5
StatePublished - May 1997


  • carbon monoxide
  • carboxyhemoglobin
  • smoking
  • sympathetic nervous system

ASJC Scopus subject areas

  • Internal Medicine


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