Exercise is undoubtedly good. This does not mean, however, that the more exercise you have the better. Dr Henry Soloman in “The Exercise Myth” reviewed 2,200 medical studies of the interrelationship between cardiovascular disease (CVD) and exercise and he found that there was no evidence that exercise slowed the progression of CVD.
Whilst it is good to be fit, it is a possibly fatal error to confuse fitness and good cardiovascular health. That is why more athletes than you might imagine succumb to CVD (see for instance Dr Harry Edwardt http://www.youtube.com/watch?v=MK_3kILU9Ug). Exercise does you good in reducing obesity, triggering release of Nitric Oxide and generally stimulating bodily functions. On the downside it generates oxygen free radicals. The more extreme/prolonged the exercise the more free radicals are released in the body and the more oxidation occurs in the arteries. Free radicals are harmful because they lack an electron and steal one from other atoms in the body setting up a possible chain reaction. Research has shown that oxidation/free radicals are the underlying initiator of over 70 chronic diseases, including heart disease (Davies, “Oxidative stress: The paradox of aerobic life,” Biochem Soc Symp, 61 (1995), 1-31).
The ideal is therefore to exercise in reasonable moderation and simultaneously to minimize oxidation by use of antioxidants, such as vitamin C, vitamin E and co-enzyme Q10. Most important of all antioxidants when it comes both to CVD and exercise is Nitric Oxide, which the body creates from the natural amino acid, L-arginine. Arginine Derived Nitric Oxide carries an extra electron and can therefore neutralize free radicals. It can resist and reverse oxidation in the arteries. Antioxidants allow you to reap the considerable benefits of exercise while minimizing the harmful effects. What is more, L-arginine supplementation can actually improve sporting performance/training endurance (http://www.sciencedaily.com/releases/2010/08/100826104137.htm). Another possible bonus is that a fascinating research paper (Jobgen et al, Journal of Nutrition, Feb 2009, 139(2): 230-37) on dietary induced obese (DIO) rats shows that Arginine supplementation reduces weight gain, reduces dangerous white fat and enhances skeletal muscle and brown fat. One last tip: if you are a bodybuilder keep your protein at least an hour away from your L-arginine – they each reduce the absorption of the other in the body.