In another study, Dujic et al. also showed that just 3 minutes of very mild exercise during ascension and decompression also reduced nitrogen bubble formation.
Finally, a mere 10 minutes of exercise at 85 percent of VO2 max significantly reduced nitrogen bubble formation. While more research is needed in sport divers, some potential conclusions can be drawn.
- High intensity (>85 percent MHR) 2 to 24 hours before or immediately after a dive likely reduces one's risk for DCS, but certainly doesn't increase one's risk.
- Very mild exercise during your ascension can help reduce your nitrogen levels, possibly due to increased ventilation, reduced nitrogen bubble formation and DCS.
- Like any activity, training specificity and overall fitness (via training) reduce one's risk for DCS (Potier et. al., 2009).
- Exercise CANNOT and SHOULD NOT alter current prescribed dive durations and decompression times on ascension, but potentially enhance nitrogen elimination.
Dujic and colleagues readily admit they are still unclear as to the exact mechanism, but they believe that the known release of nitrous oxide (NO) from the endothelial lining of the blood vessels may play a major role. This seems plausible, as NO is a key vasodilator released from the endothelium during exercise, and can be intensity driven.
Based on the current literature, it seems unwarranted to avoid exercise prior to or after a dive, and most certainly, overall health and physical fitness will minimize your risks for dive complications.