<\/p>\n
CASE 4 ANSWER<\/span><\/p>\n \n The best two studies of the relation of exertion to myocardial infarction were done in the same way.\u00a0 <\/span>People who<\/span>\u2019<\/span>d just had an MI were interviewed about their usual activities and their activities right before their MI<\/span>\u2019<\/span>s.\u00a0 <\/span>Each patient served as his own control for a comparison of the observed frequency of heavy exertion (6 or more mets – roughly, the amount of exertion in jogging, sex, and snow-shoveling ) with the expected frequency of heavy exertion given their usual activity patterns.\u00a0 <\/span>Both studies reached the same conclusions:<\/span><\/p>\n 1) The vast majority of MI<\/span>s occurred during periods of rest, <\/span><\/p>\n 2) Nevertheless there was an increased frequency during heavy exertion.\u00a0 <\/span>A German study (NEJM 12\/2\/93) yielded a relative risk of MI during exertion of 2.1.\u00a0 <\/span>An American study (same issue) yielded a relative risk of 5.9.<\/span><\/p>\n \n There are other less methodologically sound studies suggesting that arrhythmias occur more frequently during exercise.<\/span><\/p>\n \n \n \n \u00a0<\/span><\/p>\n3) <\/span>The risk of heavy exertion for habitual heavy exercisers was much less (1.3 and 2.4) than for the habitually sedentary (6.9 and 107).<\/h1>\n
\nNevertheless, the evidence discussed in Case 3, which is substantial, shows that the net effect of exercising over the long term is to substantially reduce cardiovascular mortality.\u00a0 <\/span>So, in the short run, the exercise program is deleterious and in the long run beneficial.\u00a0 <\/span><\/span><\/p>\n
\nHow to get from the short run to the long run?\u00a0 <\/span>A couple of analogies may help in advising this patient.\u00a0 <\/span>First, exercise stress testing on a treadmill with a technician or physician flogging the patient to walk faster is safe in the absence of aortic stenosis, unstable angina, severe hypertension, etc.\u00a0 <\/span>If the patient gets symptomatic, she stops.\u00a0 <\/span>The only real difference between the stress test and the home treadmill is the presence of the physician and the recording of asymptomatic ischemia.\u00a0 <\/span>Second, the situation is analagous to a pre-operative assessment of coronary risk – the stressor is exercise not surgery.\u00a0 <\/span><\/span><\/p>\n
\nSome groups – the US Preventive Services Task Force for one – recommend performing a stress test prior to beginning an exercise program in asymptomatic people with multiplecardiovascular risk factors.\u00a0 <\/span>As a widespread recommendation for everyone that is underactive (about 60<\/em>% of the adult population), it<\/span>\u2019<\/span>s expensive, but for those with multiple risks probably prudent.<\/span><\/p>\n<\/div>\n