Wednesday, July 05, 2006

Exercising After Diving - Not a Bad Thing to Do?

Here is a study reported in the Journal Aviation, Space and Environmental Medicine that reports a decline in the bubble count during strenuous exercise after a 99 foot open sea dive.

Dujic Z, Obad A, Palada I, Ivancev V, Valic Z. of the Department of Physiology, University of Split School of Medicine, Croatia report that venous bubble count declines instead of rising as feared by divers and aviators. They report this in Aviat Space Environ Med. 2006 Jun;77(6):592-6.

Here is the abstract of the article:

INTRODUCTION: The effect of post-dive exercise on bubble formation remains controversial, although the current practice of divers and aviators is to avoid strenuous exercise after diving. Previously, we have shown that exercising 24 h before a dive, or during a decompression stop, significantly reduces bubble formation in man. The objective of this study was to determine whether a short period of strenuous post-dive exercise promotes venous bubble formation.

METHODS: Seven male military divers performed an open-sea field dive to a maximum depth of 30 m for 30 min. At maximum depth, subjects performed mild underwater fin swimming, followed by standard decompression. Diving was followed by a post-dive exercise session consisting of short, strenuous incremental upright cycle ergometry, up to 85% of maximal oxygen uptake, for about 10 min. Subjects were monitored for venous gas bubbles in the right heart with an echo-imaging system starting 20 min post-dive while in the supine position, during cycle ergometry in the seated upright position, and immediately after exercise in a supine position.

RESULTS: The average number of bubbles was 1.5 +/- 1.4 bubbles x cm(-2) 20 min after diving. Changes in posture from supine to seated upright resulted in significant reduction of bubbles to 0.6 +/- 1.3 bubbles x cm(-2) (p = 0.043), with further reduction to 0.2 +/- 0.3 bubbles x cm(-2) at the end of exercise (p = 0.02). No cases of DCS or intra-pulmonary shunt were observed during or following post-dive exercise.

DISCUSSION: These results suggest that post-dive strenuous exercise after a single field dive reduces post-dive gas bubble formation in well-trained military divers. Additional findings are needed for normal sports divers.

Links to related References

References on Scubadoc's Diving Medicine Online that differ from these recommendations.