ROME -- Exercise is a hot issue for debate among the 30,000 plus doctors coming from all over to attend the annual meeting of the European Society of Cardiology at the Fiera di Roma on August 27 to 31, 2016.
According to Dr. Sanjay Sharma of St. George's University of London, United Kingdom, regular exercise reduces the risk of cardiovascular morbidity (death) and all-cause mortality by up to 50 percent and 30 percent respectively.
In general, there is a 10 to 20 percent reduction per MET when exercise between 4-12 METs. So put it in simpler terms, METs is the amount of oxygen required and consumed by the body for every physical activity that the person does, whether it is recreational like swimming or the rather vigorous strenuous activity like marathon runs. Most studies have assessed relatively few individuals capable of exercising beyond 12 METs and been unable to demonstrate any additional benefit.
Current guidelines recommend 30 minutes of moderate exercise- meaning within 4 to 6 METs (your cardiologists or your physical therapist can explain these activities) at least five times a week or 20 minutes of vigorous exercise- more than six METs at least three times weekly, however many competitive athletes and individuals engaging in recreational endurance events such as triathlon exercise more intensively than 12 METs and exceed recommendation by 10 to 15 times.
There has been a plethora of publications alluding to the potential dangers of intensive exercise in athletes with otherwise normal hearts. Some researchers have speculated that such episodes d reflect myocardial inflammation which could lead to adverse heart remodeling/enlargement and may precipitate rhythm problems or arrhythmias. Only a few studies have reported myocardial fibrosis in veteran marathon runners and these are marred by small sample size and lack of statistical significance in their results.
Cardiovascular magnetic resonance (CMR) studies performed immediately after a marathon run in individuals with increased heart concentrations have not shown any evidence of myocardial inflammation. A recent American study of 42000 sedentary (couch potatoes, if you may call them) subjects and 13000 runners reported a positive impact of jogging on cardiovascular mortality. Another study of 37000+ middle-aged individuals showed a progressive survival benefit.
Actually, the other side of the debate is not so much about exercise per se but a question of the optimal dose of exercise training and whether the so-called EEE or excessive endurance exercise could have adverse effects. Data from Wen and colleagues in over 400,000 people from Taiwan suggest that benefits from vigorous exercise seem to occur after 30-40 minutes.
However, very high doses of EEEs- prolonged duration and intensive vigorous muscular activity has the potential for cardiotoxicity, including release of troponins, brain natriuretic peptide, heart enlargement and dilatation, dysfunction of the right side of the heart and of course, a common problem, atrial fibrillation.
The researchers of both sides of the debate agreed that there is no intention to scare athletes or sports-minded folks pain marathons or triathlons and the like. The maximal benefits of exercise from a health perspective appear to occur at low levels of METs. Otherwise, for athletes gearing for the medals or trophies, it is understandable for them to engage in excessive endurance exercise.
Intuitively, too much of anything is bad for health, with the probable exception of love. For health, the evidence supports what Hippocrates said centuries ago.
"If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." And as an addendum, studies with strong statistical support have shown that former Olympians and Tour de France athletes live considerably longer than the general population.
Friendly advice dear readers and friends, before you exercise, consult your doctor. Cheers and Ciao!