|  Blunted heart rate rise during exercise an ominous sign in healthy men -
16-04-2006, 03:07 AM
In healthy middle-aged men, a blunted heart rate (HR) increase at 40% to 100% of maximal workload during an exercise test is a strong predictor of early cardiovascular disease and death, Finnish cardiologists report.
"The magnitude of the association was comparable with that of other major cardiovascular risk factors," report Dr. Kai P. Savonen from Kuopio Research Institute of Exercise Medicine and colleagues in the March issue of the European Heart Journal.
Their study involved 1,378 men between 42 to 61 years of age who had no coronary heart disease and were not using beta-blockers. They measured and recorded HR at rest and during a maximal, symptom-limited bicycle exercise test at 20%, 40%, 60%, 80%, and 100% of maximal workload.
During follow up lasting an average of 11.4 years, 56 men died of cardiovascular disease. The researchers observed that the slope of HR increase during exercise testing was significantly steeper in survivors compared with nonsurvivors, "and the difference in the steepness of HR slope between the groups was the strongest at interval 40-100% (p < 0.001)."
Maximal HR - HR at 40% workload (a.k.a., HR40-100) was inversely related to mortality due to cardiovascular disease (p = 0.04), coronary heart disease (p = 0.004), and all-causes (p = 0.002) after adjusting for known risk factors for cardiovascular death.
The average HR40-100 was 54 beats per minute in the whole study population, 55 beats per minute in survivors and 45 b.p.m in those who died (p < 0.001 for difference between survivors and nonsurvivors).
These data suggest that "a low HR40-100 can identify persons with an increased risk of cardiovascular death independent of parameters measured at rest or maximal exertion," Dr. Savonen and colleagues conclude.
The researchers caution that the association between HR40-100 and mortality needs to be confirmed in other populations, such as women, before any definitive conclusions can be made regarding its applicability as a predictor of cardiovascular death | 
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