Skip to main content

Heart Rate Variability During High Ambient Heat Exposure

Buy Article:

$22.00 plus tax (Refund Policy)

Bruce-Low SS, Cotterrell D, Jones GE. Heart rate variability during high ambient heat exposure. Aviat Space Environ Med 2006; 77:915–920.



Introduction: This study observed heart rate variability (HRV) measured in order to detect the changes in sympathovagal activity during high ambient (74°C) temperature. HRV is a measure of heart rate (HR) fluctuations around the mean HR and has been used to indicate the balance between parasympathetic and sympathetic function of the autonomic nervous system in medicine and exercise, but not in extreme environments. Methods: There were 10 healthy male subjects who wore Polar HR monitors (PE 5000) during a 15-min exposure (74.3 ± 5.9 °C). Results: HR increased significantly (p < 0.05) from 66.5 bpm pre-exposure to 106.0 bpm during exposure to the dry heat. A significant decrease in parasympathetic drive was indicated by: 1) a reduction of 89.1 ± 31.3% in the proportion of interval differences between two normal R-R intervals that were in excess of 50 ms in length (pNN50); 2) an 83.4 ± 7.0% decrease in the root mean square of successive R-R differences (RMSSD); and 3) an 82.7 ± 11.4% decrease in the normalized high-frequency (HF norm) values. An increase in a sympathetic drive was indicated by a significant increase in: 1) the normalized low-frequency (LF norm) values (of 84.5 ± 19.4%); and 2) the LF:HF ratio (10.9 ± 10.8%). Discussion: The results from this study show that exposure to high ambient temperature produces a significant increase in HR through an increase in sympathetic and decrease in parasympathetic drive.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Keywords: environmental; stress; sympathovagal balance

Document Type: Research Article

Publication date: 2006-09-01

More about this publication?
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
X
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more