Yearlong physical activity and regional stiffness of arteries in older adults: the Nakanojo Study

Our objectives were to test the hypothesis that the habitual physical activity of elderly individuals is associated with less arterial stiffening, to explore characteristics of any dose/response relationship, and to determine those segments of the arterial tree where associations are most apparent. Participants (89 men and 109 women, aged 65-84) wore a pedometer/accelerometer continuously for 1 year. The daily step count and the duration of moderate-intensity activity (>3 metabolic equivalents, METs) were recorded. At year's end, an automatic waveform analyzer determined the pulse wave velocity between five recording sites: the aortic root, and the carotid, brachial, femoral and tibial arteries. After appropriate adjustments for sex, age, and mean arterial pressure, overall (delta brachio-tibial "velocity") and central arterial stiffness (cardio-femoral velocity) showed small but statistically significant negative correlations with daily step count and the duration of activity >3 METs. Cardio-carotid velocity was also associated with step count. In contrast, cardio-brachial and femoro-tibial velocities were not significantly related to either estimate of habitual activity. Cardio-femoral and delta brachio-tibial velocities were significantly lower in physically active individuals, apparently reaching a minimum in subjects who exceeded counts of about 6,600 steps/day and/or exercised for more than 16 min/day at an intensity >3 METs. The data support our hypothesis, showing weak but statistically significant associations between habitual physical activity and pulse wave assessments of arterial stiffness in elderly adults. Further studies are recommended to test the causality of these associations and to explore why relationships seem more marked for central than for peripheral arterial segments.