Exercise and Decompression Sickness

[Shae]

I've read that exercising heavily after diving can increase the risk of developing decompression sickness. I was wondering, is there any risk with exercising before a dive? Specifically, will running a few miles (3-5) before a dive compromise my health in diving?

-Shae

 

[Don Burke]

I found this on:
http://www.ncbi.nlm.nih.gov

I used Blatteau as a search term.

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Aerobic exercise 2 hours before a dive to 30 msw decreases bubble formation after decompression.

Blatteau JE, Gempp E, Galland FM, Pontier JM, Sainty JM, Robinet C.

CEMPP, Toulon Armees, France. je.blatteau@infonie.fr

BACKGROUND: A single bout of aerobic exercise 24 h before a dive significantly reduces the formation of circulating venous gas emboli (VGE) on decompression. The purpose of this investigation was to determine the effect of aerobic exercise 2 h before a dive. METHODS: There were 16 trained military divers who were compressed to 30 msw (400 kPa) for 30 min breathing air in a dry hyperbaric chamber at rest, then decompressed at a rate of 10 m x min(-1) with a 9-min stop at 3 msw. Each diver performed two dives 3 d apart, one with and one without exercise that consisted of running for 45 min at 60-80% of maximum heart rate (estimated as 220 - age). VGE were graded according to the Spencer scale using a pulsed Doppler detector on the precordium at 30 min (T30) and 60 min (T60) after surfacing. RESULTS: Mean bubble grades at T60 were 1.25 for control dives and 0.44 for dives preceded by exercise, the difference being highly significant. None of the divers showed an increase in venous bubble grade after exercise. CONCLUSION: Like exercise 24 h ahead, 45 min of running 2 h before a dive decreases bubble formation after diving, suggesting a protective effect of aerobic exercise against DCS. The threshold of exercise intensity and duration necessary to change venous circulating bubbles is unknown. Mechanisms underlying the protective effect of exercise remain unclear. Rather than altering the nitrogen elimination rate, exercise may affect the population of gaseous nuclei from which bubbles form.

PMID: 16018350 [PubMed - in process]

 

[chip104]

Hi shae,

check out the marine science & physiology forum. There's a bunch of info there.

Here was the most recent discussion of it in the accidents and incidents forum.

http://www.scubaboard.com/showthread.php?t=111012


When looking at the abstracts of studies, try keep an open mind in interpreting the data. Hope you find what you're looking for.

 

[CameronMartz]

I've read that exercising heavily after diving can increase the risk of developing decompression sickness. I was wondering, is there any risk with exercising before a dive? Specifically, will running a few miles (3-5) before a dive compromise my health in diving?

-Shae

The short answer is "we don't think so." The long answer is that researchers are looking at this very question right now, and preliminary results seem to indicate that pre-dive exercise might actually be protective, assuming that you do not allow yourself to become dehydrated or overly fatigued. Not enough research has been done to make outright recommendations, but when looking at real-world accident data, it is very difficult to find specific cases of DCS that were caused by pre-dive exercise. Note that post-dive exercise, when done with tissues in a state of supersaturation, is entirely different and has resulted in DCS both in the lab and real-world.

DAN's formal recommendations are to wait 4 hours after exercise before diving, though this is based upon research on decompression to altitude performed by Dr. Deco and others. For divers, this research actually better represents what would happen if you were to exercise at depth on a saturation dive, rather than exercise on the surface before diving.

Check out this thread for more info:
http://www.scubaboard.com/showthread.php?t=108893&highlight=exercise

Cameron

 

[Shae]

The link was great, thanks for the help.

-Shae