Faculty Collaboration Database

Carotid baroreflex responsiveness in high-fit and sedentary young men. J Appl Physiol (1985) 1988 Nov;65(5):2190-4

Date

11/01/1988

Pubmed ID

3209562

DOI

10.1152/jappl.1988.65.5.2190

Scopus ID

2-s2.0-0024235365 (requires institutional sign-in at Scopus site)   47 Citations

Abstract

The influence of fitness on cardiac vagal activity and baroreflex-mediated control of heart rate has not been clearly established in humans. Therefore, we studied resting cardiac vagal activity by evaluating respiratory sinus arrhythmia (RSA) and examined carotid-cardiac baroreflex responsiveness with a neck collar in 11 high-fit and 9 sedentary [based on maximal O2 consumption (VO2max) and history of physical activity] healthy young men (19-31 yr of age). Resting cardiac vagal activity was determined from the standard deviation of 100 consecutive resting R-R intervals. Baroreflex responsiveness was determined from the R-R interval responses to neck suction and pressure (repeated trials of 5-s stimuli of -20, -40, and 35 mmHg). Both RSA and the bradycardic (R-R interval) responses to neck suction of -40 mmHg were significantly greater (P less than 0.05) in the high-fit individuals (RSA, 116.5 +/- 11.5 ms; neck-suction response, 145.3 +/- 17.0 ms; mean +/- SE) compared with sedentary subjects (RSA, 65.2 +/- 6.6 ms; neck-suction response, 86.9 +/- 12.5 ms). Responses of the high-fit volunteers to the other intensities of neck stimuli (-20 and 35 mmHg) showed a similar trend but were not significantly different from those of the sedentary volunteers. The baroreflex slope derived from these data was significantly greater in the high-fit subjects (4.00 +/- 0.39 ms/mmHg) compared with the sedentary controls (2.53 +/- 0.28 ms/mmHg). These data suggest that resting cardiac vagal activity is greater, carotid-to-cardiac activity is well maintained, and baroreflex sensitivity, i.e., slope, is augmented in high-fit subjects.

Author List

Barney JA, Ebert TJ, Groban L, Farrell PA, Hughes CV, Smith JJ

Author

Thomas J. Ebert MD, PhD Adjunct Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Adult
Arrhythmia, Sinus
Carotid Sinus
Heart Rate
Humans
Male
Physical Fitness
Pressoreceptors
Reflex
Vagus Nerve