Breathing Kills

I am seldom more at peace than when reading about a good health scare. Judge, then, of my contentment when I read this story. It tells us, apparently, that smokers are at greater risk of HIV. But, as with all health scare stories, this is not what it seems. Smoking does seem to impair the immune system so you might be more likely to get HIV or, indeed, Dengue Fever. But, in fact, the slender statistical link they seem to have discovered could also arise because smokers take more sexual risks than non-smokers. This is, of course, not science but pure speculation based on the vague prejudice that smokers are bad people. By the time we get to the end of the story the scientist has been reduced to saying that people with HIV shouldn't smoke because of the risks of heart disease and cancer. Well, er, yes. Meanwhile, I am also flooded with a great sense of peace by the news that gentle walking is no good for your health. In fact, only more intensive exercise works. That said, intensive exercise does release more free radicals, increasing your risk from cancer. Also quite a lot of people have heart attacks during exercise. The great James Lovelock once pointed out to me that, to a rough approximation, there is only one cause of cancer - our unwise decision to breath oxygen, a fabulously toxic substance. All else, smoking included, is statistically irrelevant. Breathing kills. Now there's a real health scare.