Seasonal Blood Pressure Variation and Its Relationship to Environmental Temperature in Healthy Elderly Japanese Studied by Home Measurements

The purpose of the present study was to examine seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese, as studied by home measurements. Fifteen healthy elderly Japanese (79.3 ± 5.9 yrs) measured their blood pressure at home each morning for more than 25 times per month for 3 years. Monthly mean outdoor temperatures were obtained from the Takamatsu meteorological Observatory. The highest levels of systolic and diastolic blood pressure measured at home were observed in February (129 ± 14 and 81 ± 13 mmHg). The lowest levels of systolic and diastolic blood pressure measured at home were observed in August (117 ± 11 and 73 ± 10 mmHg). Likewise, the lowest and highest means of outdoor temperature were observed in February (5.0°C) and August (29.2°C), respectively. Hence, both systolic and diastolic blood pressure demonstrated a close inverse correlation with the means of outdoor temperature (r = −0.973, p < 0.001 and r = −0.985, p < 0.001, respectively)...