Exercise and diving

[gcbryan]

A fairly common practice in shore diving is to do surface swims (sometimes longish ones) to a drop down point.

Sometimes this may be unavoidable as when at a shallow dive site but since exercise and diving don't mix that well regarding bubble formation isn't this a rather poor practice at deeper sites where more nitrogen will likely be ongassed in the course of the ensuing dive?

If the Navy has divers exercising to be able to quickly get the 5% hits for table research it strikes me as odd that so many divers begin many shore dives with surface swims where they aren't totally necessary..meaning that they could just drop down at the beach and just use more gas.

What are your thoughts on this practice. Is it not enough exercise to be meaningful or should it be reduced?

[ptyx]

If you're in good shape, a surface swim is not necessarily a lot of effort.

That said, on shore dives I try as much as possible to do the surface swim on the way out only, and come back underwater with a nice triangular profile. Avoiding exertion is only one of the many reasons to do so (gotta use that air, after all!).

In any case, I'd be more concerned about the walk in the sand and under the sun to the staging area than the swim back.

[Jeff Toorish]

Gearing up with doubles on a dive boat, doing a deep dive, them struggling back onto the boat is probably more exercise than a surface swim.

Jeff

[vladimir]

A fairly common practice in shore diving is to do surface swims (sometimes longish ones) to a drop down point.

Sometimes this may be unavoidable as when at a shallow dive site but since exercise and diving don't mix that well regarding bubble formation isn't this a rather poor practice at deeper sites where more nitrogen will likely be ongassed in the course of the ensuing dive?

If the Navy has divers exercising to be able to quickly get the 5% hits for table research it strikes me as odd that so many divers begin many shore dives with surface swims where they aren't totally necessary..meaning that they could just drop down at the beach and just use more gas.

What are your thoughts on this practice. Is it not enough exercise to be meaningful or should it be reduced?

I don't think moderate pre-dive exercise adds to the risk of DCS. It may even mitigate it somewhat. Exercise during and immediately after the dive is to be avoided.

[gcbryan]

I don't think moderate pre-dive exercise adds to the risk of DCS. It may even mitigate it somewhat. Exercise during and immediately after the dive is to be avoided.

As I recall the Navy did it before the dive (I could be wrong here however).

To address some of the other post's ... I don't think it's the cardiovascular aspect of the exercise that causes the problem...I think it's the kinetic aspect.

Anyway, perhaps Dr. Deco has some input.

[vladimir]

A quick search turned up this post, which discourages exercise the day of the dive:

Weight Lifting and Deco Diving

Hello Lora :

I have not heard of any negative effects of exercise one day, or more, before a dive. There is actually some laboratory evidence – in rats - that exercise a day before the dive is beneficial. The researchers relate this protective effect to the formation of nitric oxide, a substance believed to have some effect on the capillaries.

There is considerable controversy regarding injury [minor anyway] and the location of DCS. A study by the Air Force did not support the claim.

Exercise prior to the dive [on the same day] is not good, according to my studies, as well as many others. This is hypothesized to be the result of micronuclei formation in the capillaries and tissues. These can then grow during the ascent phase of the dive and produce DCS.


Dr Deco

I did see some posts that suggest that exercise 24 hours before a dive might be beneficial; obviously not relevant to your question but perhaps the source of my confusion.

[Dr Deco]

It appears that predive exercise is less harmful than I originally suspected. Predive exercise forms microbubbles but these are reduced in size by the pressurization of the dive. Exercise at depth and following the dive [on the surface] is harmful with respect to DCS.