Baroreflex modulation of sympathetic nerve activity to muscle in heat-stressed humans

Jian Cui, Thad E. Wilson, Craig G. Crandall

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


To identify whether whole body heating alters arterial baroreflex control of muscle sympathetic nerve activity (MSNA), MSNA and beat-by-beat arterial blood pressure were recorded in seven healthy subjects during acute hypotensive and hypertensive stimuli in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature (P < 0.01), MSNA (P < 0.01), heart rate (P < 0.01), and skin blood flow (P < 0.001), whereas mean arterial blood pressure did not change significantly (P < 0.05). During both normothermic and heat stress conditions, MSNA increased and then decreased significantly when blood pressure was lowered and then raised via intravenous bolus infusions of sodium nitroprusside and phenylephrine HCl, respectively. The slope of the relationship between MSNA and diastolic blood pressure during heat stress (-128.3 ± 13.9 U·beats-1·mmHg-1) was similar (P = 0.31) with normothermia (-140.6 ± 21.1 U·beats-1·mmHg-1). Moreover, no significant change in the slope of the relationship between heart rate and systolic blood pressure was observed. These data suggest that arterial baroreflex modulation of MSNA and heart rate are not altered by whole body heating, with the exception of an upward shift of these baroreflex curves to accommodate changes in these variables that occur with whole body heating.

Original languageEnglish
Pages (from-to)R252-R258
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number1 51-1
StatePublished - 2002


  • Baroreflex sensitivity
  • Heart rate
  • Heat stress
  • Muscle sympathetic nerve activity

ASJC Scopus subject areas

  • General Medicine


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