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Diving and its accidents (DCS and O2 hits) are not the principal risks of death in divers; ischaemic heart disease is. Heart attack is the leading cause of death in men and women over the age of 35 in the US and most developed and developing countries. In all recent DAN reports, death by heart attack far outnumbers other causes of in-water death in divers. As the average age of divers increases, these deaths are also likely to increase. Several recent, large studies provide information on how the risk of heart attack can be assessed and reduced. Whatever the means to achieve it (diet & exercise alone or in combination with drugs), every 1% reduction in cholesterol (actually LDL and "bad" triglycerides) results in a 2% reduction in heart attack (fatal and non-fatal). This translates into about a 30% reduction in risk of heart attack for people who are able to get their cholesterol into the recommended range and is true for people who have have *not* had a previous heart attack, as it is for people who have. Importantly, reducing your cholesterol does *not* increase your risk for other diseases, e.g., cancer. It seems that the most dangerous type of blockages (called plaques) to the coronary arteries are those which only partially block the blood vessel. These are more prone to "burst" into the blood stream and cause a clot in the artery, which tends to ruin your whole day as oxygenated blood is prevented from passing the clot and getting to the heart muscle. Of 1.5 million people who get heart attack each year, at least 30% die right away. As noted in previous posts, if when the plaque bursts, aspirin is "on board", it may reduce the local clotting reaction and permit blood to continue flowing to the heart. This is probably the basis by which small doses (a "baby" aspirin a day or a whole one, 3-5 times a week) reduces the overall heart attack rate, compared with people not taking aspirin. But aspirin may do little to prevent plaques forming in the first place. In a large published study, people who were on cholesterol lowering treatments (which we know both reduce the size of existing plaques and reduce the formation of new ones in people with high cholesterols) *and* who were taking >100 units of Vitamin E per day had an additional reduction in plaque formation or further reduction in the size of existing plaques. Vitamin E's effect probably works by helping metabolize "bad" cholesterol. Note that, for reasons not really understood, women respond to cholesterol/plaque reduction treatments somewhat better than men. Probably, if they participate in treatment studies, they tend to have earlier disease than the men in same studies: A reason for men to get on the ball *before* any symptoms of heart disease appear. A very recent study indicates that measuring the thickness and "roughness" of the carotid artery wall with ultrasound (sonar) can give much the same information about who is at risk for a heart attack, as does the much more risky/expensive procedure of injecting dye into the coronary arteries. So whether aspirin works for DCS, in non-allergic divers, it's worth taking. And the risk/expense of taking about 400 IU of vitamin E a day is also worth it. Note that none of these treatments *replaces* having your cholesterol/triglycerides measured (and treated under medical supervision if needed), exercising regularly and eating a fat-reduced diet. Additionally, new non-invasive tests may pinpoint people at special risk for heart attack. Safer diving through bloodier hearts Peter Heseltine, MD P.S. E-mail me if you want the medical publication references to the above.
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