[Circadian rhythmicity of heart rates in centenarians].

Holter electrocardiography was used to study the circadian rhythm of heart rate in 50 centenarians living in Tokyo and in Aichi prefecture. As a control group, 50 healthy subjects aged under 65 years old underwent medical check-ups including Holter electrocardiography at Keio Health Consulting Center. Harmonic analysis was used to approximate the 24-h time-series data on the RR intervals to a summation of three cosine waves with 24-h, 12-h and 8-h periods. The power of each period was adjusted for the goodness of the curve-fit, and the powers of the centenarians were compared with those of the controls. Then all the subjects were classified by k-means cluster analysis into k groups based on the power of the period, and patterns of heart rate rhythms were then identified. The power of the 24-h period in centenarians (32.7 +/- 16.0%) was significantly lower than that in controls (45.8 +/- 17.8%). Although there were no significant differences in the powers of the 12-h and 8-h periods, the power of the 8-h period in centenarians (7.0 +/- 8.4%) was slightly higher than that in controls (4.2 +/- 3.3%). Advances or delays in acrophase (acrophasal shift) were more common in centenarians than in controls. Five patterns of heart rate rhythms were identified: 24-h period dominant (n = 58). 24-h + 12-h period (n = 15), 12-h period dominant (n = 7), 8-h period augmented (n = 7), and low curve-fitting (n = 13). Both the 8-h period augmented pattern and the low curve-fitting pattern were more common in centenarians than in controls. Both the 24-h period dominant pattern and the 24-h + 12-h period pattern were less common in centenarians than in controls. These data indicate that the circadian rhythm of heart rate changes with aging.