Increased plasma beta-endorphin immunoreactivity in scuba divers after submersion

Area of Science:

• Exercise Physiology
• Neuroendocrinology
• Diving Medicine

Background:

• Scuba divers often report euphoria after submersion, similar to exercise-induced feelings.
• Strenuous exercise is known to increase beta-endorphin immunoreactivity (beta-EIR) due to stress.

Purpose of the Study:

• To investigate if underwater submersion in a neutral buoyancy state increases plasma beta-EIR.
• To determine if this occurs without strenuous exercise or extreme stress.

Main Methods:

• Male scuba divers were studied before and after motionless submersion at 10 ft.
• Plasma beta-EIR levels were measured using radioimmunoassay.
• Control measurements included venipuncture and breathing outside water.

Main Results:

• A significant increase (P < 0.01) in plasma beta-EIR was observed after submersion.
• Neither venipuncture nor breathing scuba outside water affected beta-EIR levels.
• Results indicate submersion is a mild stressor that elevates beta-EIR.

Conclusions:

• Underwater submersion in a neutral buoyancy state elevates plasma beta-EIR in scuba divers.
• This suggests a physiological stress response similar to that of severe stress.
• The findings link the euphoric feelings reported by divers to neurochemical changes.