Physical training and heart rate and blood pressure variability: a 5-yr randomized trial.

We studied the effect of regular physical activity on cardiac and vascular autonomic modulation during a 5-yr controlled randomized training intervention in a representative sample of older Finnish men. Heart rate variability (HRV) and blood pressure variability (BPV) are markers of cardiac and vascular health, reflecting cardiac and vascular autonomic modulation. One hundred and forty randomly selected 53- to 63-yr-old men were randomized into two identical groups: an intervention (EX) group and a reference (CO) group, of which 89 men remained until the final analysis (EX: n = 47; CO: n = 42). The EX group trained for 30-60 min three to five times a week with an intensity of 40-60% of maximal oxygen consumption. The mean weekly energy expenditure of the training program for the 5-yr training period was 3.80 MJ, and 71% of the EX group exceeded the mean. The EX group had a significantly (P < 0.01) higher oxygen consumption at ventilatory aerobic threshold (VO2VT) than the CO group at the 5-yr time point. VO2VT had a tendency to increase in the EX group and decrease in the CO group (interaction P < 0.001) from the baseline to the 5-yr time point. Peak performance did not change. Low-frequency power of R-R interval variability decreased in the EX group (P < 0.01, by 6%) from the baseline to the 5-yr time point. BPV did not change. In conclusion, low-intensity regular exercise training did not prevent HRV from decreasing or change BPV in 5 yr in older Finnish men.