3 months ago

AD 2016 Q2

As we pointed out in the spring 2013 edition of the Alert Diver, even being a dive buddy has potential legal implications. So, to bump this up a notch, what about the diver training organisations themselves? Where do they stand? How do they relate to South African law? Are they all considered the same under our legal system in spite of the differences in organisational structures and training programmes? How does this affect their respective instructors and trainee divers from a legal perspective? These are not exactly simple questions. It is certainly true that the respective training organisations differ in a number of ways. However, this does not imply that there are necessarily differential legal implications for each of them. In fact, under South African law, the legal principles are common in all matters. Therefore, if you suffer a loss and you (or your estate in the case of a fatality) wish to recover damages, the legal principles would be applied commonly; whether you are driving or diving. Although not a frequent occurrence, there have been quite a number of law suits associated with diving injuries and damages in South Africa. This is not surprising, as the occurrence of law suits is really a function of “numbers”. As training increases, so do the chances of injuries and, with it, the chances of legal recourse. So, it remains wise to insure yourself, your equipment or your business in a proper and effective way. But before getting back to the potential differences amongst the training agencies, let’s first explore the foundational legal principles on which any civil claim would be adjudicated: inherent risk, negligence and duty to take care.

Despite a small number

Despite a small number of subjects, these findings prompted discussion among divers about the use of vitamin C to protect them from possible adverse health effects of diving. Evidence-based justification is not yet available. It is not known what transitory endothelial dysfunction means for long-term health or if vitamin C can provide divers with any measurable health benefits. Regular intake of vitamin C is necessary for health maintenance, but the recommended dose is about 100 mg per day, which can be obtained from one orange or a serving of green vegetables. The dose for treatment of scurvy is 400 to 1,000 mg per day for one week, and the maximum recommended dose is 2,000 mg. There is no evidence that higher doses of vitamin C improve health. CHOCOLATE Cocoa contains polyphenols, flavonoid compounds with antioxidant effects, blood-thinning properties and possibly other beneficial effects. The mechanisms involved in these effects include reduction of oxidative stress and increased production of endothelial NO, which supports normal endothelium-dependent vasodilation. This reportedly both lowers blood pressure and reduces risk of heart disease. The majority of studies claiming benefits of chocolate are small-scale studies sponsored or even conducted by chocolate manufacturers. Benefits of chocolate have been tested in both breath-hold and scuba divers. The scuba dive study was conducted in 91°F water at 108 feet (33 msw) for 20 minutes with no decompression stop. Twenty-one divers ate 30g of dark chocolate (85 percent cocoa) 90 minutes before the dive, while 21 divers in the control group did not have chocolate. The breath-hold study had 10 divers in the chocolate group and 10 in the control group. Both studies found that dark chocolate reduced endothelial dysfunction. Further studies conducted by the same authors found that eating chocolate had no effect on the amount of postdive venous gas bubbles. WINE In vitro studies of resveratrol, a compound found in wine, showed antioxidant and other effects that may provide protection against aging, various diseases and death. Further animal studies appeared to confirm the beneficial effects. Among the benefits were effects on skeletal and cardiac muscle functions similar to the effects of endurance exercise training. It was also claimed that resveratrol improves perfusion of the brain and provides neuroprotection, both of which may be helpful in reducing the risk of decompression sickness (DCS). Because resveratrol is suspected to prevent endothelial cell dysfunction and platelet aggregation, some scientists assumed it may help prevent DCS. Recent resveratrol studies claimed several additional health benefits that could be appealing to divers, but the amount of resveratrol used in these studies would require drinking JUDITH FLACKE/ISTOCKPHOTO.COM 84 | SPRING 2016

OLGA KRIGER/ISTOCKPHOTO.COM 50 to 3,000 liters of wine per day. In studies of whole wine, benefits could not be determined in light of the confounding effects of alcohol consumption. BEET JUICE Beets are a great source of nitrates, which the body can change into NO. Some studies have found that NO can promote improvement in FMD, lowered blood pressure, decreased oxygen needs for the same level of exercise and enhanced exercise performance. Mechanisms for such enhancements at the cellular and muscular tissue levels, however, were not found. Other studies contradict these findings and claim no effect of nitrate supplementation on exercise performance or other physiological functions. Researchers studied the use of NO supplements in divers with the rationale that NO may be involved in bubble formation and the endothelial damage caused by bubbles. In one study, nitroglycerin (an NO donor) was given intravenously to animals 30 minutes before decompression from a threehour, 130-foot (40-m) dive. The amount of venous gas bubbles after decompression was 10 times less in experimental animals than in controls. Researchers also tested nitroglycerin in open-water scuba divers to 100 feet (30 m) for 30 minutes and in hyperbaric chamber dives to 60 feet (18 m) for 80 minutes. The same divers did each dive twice. Thirty minutes before the second dive in the same conditions, divers received nitroglycerine by oral spray. The postdive amount of venous gas bubbles detected in divers was smaller when they received nitroglycerine before the dive. These findings seemed promising at the time, but the evidence was not sufficient to consider recommendation of nitroglycerine to divers — the potential benefit was demonstrated in experiments involving extreme exposures not common in recreational diving. Since that study, no other research has reproduced these results or moved further toward a possible practical application. Nitroglycerin is a powerful drug that should not be used without a prescription. It can cause side effects when taken alone or in interaction with other drugs or supplements and thus should not be taken for diving. Supplements with L-arginine (another NO donor) may help to lower blood pressure, and people who take it should be aware of possible interactions with any medications they are using. Beet juice, on the other hand, may be added to your diet without much cause for concern. Just remember that neither of these products has been proven to offer specific protective effects for divers. TO SUPPLEMENT OR NOT TO SUPPLEMENT Consuming dietary supplements and certain foods may change the availability of substances such as NO that participate in basic physiological processes. It may even cause measurable but temporary changes in some functions such as FMD. In experimental settings it may affect the amount of venous gas bubbles present after dives. But these effects are not so pronounced as to suggest, for example, that an antioxidant will decrease the risk of DCS in real-life diving or that without these supplements diving would lead to long-term health problems. The U.S. Preventive Services Task Force, which regularly reviews evidence and provides recommendations, found that vitamin C, vitamin E and some other minerals and supplements studied provide no benefit to healthy subjects with regard to heart disease, cancer and mortality. 1 Many other supplements on the market make various health claims with little or no supporting evidence. A healthy and balanced diet will provide all the micronutrients you need. If you like chocolate, beware of excess sugar. If you drink wine, enjoy it in moderation, and do not drink before diving. Remember, your safety underwater depends on your dive behaviors and good judgment, not the foods you eat. AD ISTOCKPHOTO.COM Reference 1. Fortmann SP, Burda BU, Senger CA, Lin J, Beil T, O’Connor E, Whitlock EP. Vitamin, Mineral, and Multivitamin Supplements for the Primary Prevention of Cardiovascular Disease and Cancer: A Systematic Evidence Review for the U.S. Preventive Services Task Force. Evidence Report No. 108. AHRQ Publication No. 14-05199-EF-1. Rockville, Md.: Agency for Healthcare Research and Quality; 2013. ALERTDIVER.COM | 85

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