Seasonal changes in blood pressure may be partially explained in thermoregulatory terms. We hypothesized that the seasonal variation in blood pressure is related to body mass index, due to the increased thermoregulatory requirements of leaner individuals. Ambulatory systolic and diastolic blood pressure were monitored once each in summer and winter in 101 healthy normotensive men aged 28 to 63 years. Environmental conditions and body mass index were measured. The population was divided according to quartiles of body mass index. The percentage of subjects with systolic blood pressure increases of more than 10 mm Hg from summer to winter was highest among subjects in the lowest body mass index category, and lowest among those in the highest body mass index category (35% and 8%, respectively, P < .0001). After adjusting for possible confounders, the change in mean systolic blood pressure from summer to winter was inversely associated with body mass index (β = - 0.26, P = .0149). There was no association between diastolic blood pressure change and body mass index. The increase in systolic blood pressure from summer to winter is inversely and independently associated with body mass index. Hypertension research and epidemiological blood pressure studies should take into account the interaction between season, body mass index, and blood pressure. It may also be important to assess hypertension and response to antihypertensive treatment in relation to season, particularly in lean hypertensives.
Bibliographical noteFunding Information:
iagnosis of hypertension is traditionally based on casual blood pressure readings. A positive association between body D weight and hypertension has been established on the basis of such readings. ~ 3 However, Received December I3, 1995 Accepted June 3, 1996 From the Occupational Health & Rehabilitation Institute, Raa-nana, Israel (EK-B, GH, JR), and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (MSG, JR) This study was supported by the Committee for Preventive Action and Research in Occupational Health, The Ministry of Labor and Social Affairs, Jerusalem, Israel. Address correspondence and reprint requests to Dr. E. Knstal-Boneh, Occupational Health & Rehabilitation Institute, P O.B. 3, Raanana 43100, Israel.
- blood pressure
- body mass index
ASJC Scopus subject areas
- Internal Medicine