Accession Number:

AD0731675

Title:

Mechanism of the Bradycardia of the Diving Syndrome as Seen in Divers Using Scuba in Water of 55, 45, and 35 Degrees F.

Descriptive Note:

Technical rept.,

Corporate Author:

NAVY CLOTHING AND TEXTILE RESEARCH UNIT NATICK MASS

Personal Author(s):

Report Date:

1971-08-01

Pagination or Media Count:

18.0

Abstract:

Physiologists monitored heart rates of test subjects using SCUBA gear under water. Comparisons were made between heart rates immediately before and after subjects entered the water, and at 5-minute intervals while they were immersed in water. Data showed a difference in percent of decrease when initial heart rates were 90 and above or less than 90. However, data showed the decrease to be maximal within 5 minutes of submersion within a return towards presubmersion levels after 30 minutes. It is believed that initial heart rate changes were brought about immediately by a reflex vagal response to immersion. Increased venous return due to water pressure is the apparent cause of the longer term effect. A physiological adaptation to the pressure allowed return towards control values by the end of the 30-minute period. Author

Subject Categories:

  • Stress Physiology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE