Exercise Is Not Always Beneficial
If you have a heart disease or condition, high-intensity exercise for long stretches could actually increase your chance of a massive heart attack or stroke, recent studies found.
In the first of two studies 31 in Heart, German researchers spent a decade studying the 32 and intensity of weekly exercise in 1,000 people in their 60s with coronary artery heart disease (冠心病), almost half of whom were 33 2-4 times a week. Predictably, participants who 34 less than 2 times a week were determined to be at greater risk for a heart attack. However, counter-intuitively (直觉地), participants who exercised more than the average were also twice as likely to have a heart attack or stroke than the average.
A different study found that young men who engage in endurance exercise more than five hours a week may 35 their risk of developing an irregular heart rhythm later in life.
Swedish researchers surveyed 44,000 men, ages 45-79, about their exercise 36 at ages of 15, 30, 50 and over in 2013. Those who exercised 37 for more than five hours a week were 19% more likely to have developed an irregular heartbeat, which is a 38 factor in stroke risk.
Despite their findings, researchers 39 sounding the alarm full-force on intense exercise, citing the "benefits of exercise" while clarifying that "the studies reviewed here, and future studies, will serve to maximize benefits obtained by 40 exercise while preventing undesirable effects of intense exercise."

A.active               E.density             I.frequency       M.largely
B.avoided            F.energetic          J.increase          N.published
C.behavior          G.engagement    K.intensely        O.regular
D.consequently   H.exercised         L.key

33（）