Obesity has been long considered a risk factor for decompression sickness (DCS). It has been based on findings in animal studies and epidemiological data in military diving. There was no data to confirm the same effects of obesity on incidence of DCS in recreational diving; however, there were some studies indicating a positive correlation between body mass index (BMI) and likelihood of venous gas emboli (circulating gas bubbles) after dive.
In a recent paper, Kaczerska D, et al. The influence of high-fat diets on the occurrence of decompression stress after air dives. UHM 2013;40(6):487-497, intended to test possible effects of high fat intake on risk of DCS.
How does obesity affect your heart and why can obese divers develop heart trouble at apparently low level of exertion?
Obesity is an escalating problem and is linked to a spectrum of cardiac dysfunctions that affect feeling of wellbeing, physical fitness and longevity. In a recent review paper Rider O.J. et al, summarize current knowledge about how obesity affects the heart. The most notable fact is the change of source of the fuel from which the heart derives its energy. By excluding glucose and relying mostly on fatty acids, the energy process becomes less efficient and the heart needs more oxygen for the same level of work. In the long run, lipids become toxic for heart cells and lead to structural changes and weakening of the heart muscles, which is disabling and life threatening. In case of divers who feel fit enough to dive, however, the danger comes from the increased needs of heart for oxygen even at rest. In some cases, even a small increase in exercise level may cause a significant hypoxia of heart muscles which can lead to major troubles.
The good thing is that the problem can be improved by moderate weight loss. However, weight regulation should be started sooner rather than later when changes may become irreversible.
Read the full paper: OJ Rider, P Cox, D Tyler, K Clarke and S Neubauer. Myocardial substrate metabolism in obesity. International Journal of Obesity (2013) 37, 972–979; doi:10.1038/ijo.2012.170; published online 16 October 2012
Learn more from DAN FAQs: Healthy But Overweight
Post written by: Petar Denoble, MD, D.Sc.