Effect of physical training on QTc interval in elderly people

In order to assess whether heart rate-adjusted QT duration (QTc) is reduced by physical activity in an elderly population, a randomized, controlled intervention study of the effect of a 6-month intensive training program on QTc was undertaken. The participants were 229 healthy men and women, aged 60-80 years. The subjects of the intervention group trained three to four times a week at a work load of about 70% of their maximum capacity for 6 months, while the control subjects maintained their habitual activities. The main outcome measures were change in QTc and resting heart rate. For women, the mean QTc interval (ms) of the intervention group changed by -6.7 (SE 2.8) versus 0.6 (SE 2.4) in the control group (P = .05), while for men, the change in the intervention group subjects was -2.7 (SE 2.2) versus 0.4 (SE 3.1) in the control subjects (P = .39). Also, resting heart rate (beats/ min) changed in intervention group women by -4.6 (SE 1.7) as against -0.06 (SE 1.1) in the control subjects (P = .02), and in intervention group men it changed by -3.2 (SE 1.2) versus -0.9 (SE 1.5) in the control subjects (P = .25). These data indicate that regular physical activity favorably affects QTc in elderly women. A similar, but not significant, trend was observed in men. The beneficial shift in QTc may be caused by a more favorable autonomic balance through increased parasympathetic activity. The reduced resting heart rate in subjects of the intervention group supports this view. Although the reduction was relatively small, it may represent a favorable effect on cardiovascular risk.