EFFECT OF A WESTWARD TRANSMERIDIAN FLIGHT ON AMBULATORY BLOOD-PRESSURE MONITORING IN NORMOTENSIVE SUBJECTS

Objective To evaluate the effects of a westward transmeridian flight o ver six time zones (from Milan to New York) on ambulatory blood pressu re monitoring (ABPM) in normotensive individuals. Methods Eighteen nor motensive subjects (blood pressure < 140/90 mmHg), 11 men and seven wo men, of mean age 38.3 years, were studied, On the day of travel they u nderwent 26 h noninvasive ABPM (started at 1100 h); the take-off time was 1200 h and the landing time was 8 h later, at 1400 h New York time (2000 h Italian time), Subjects were requested not to sleep until 230 0 h and to get up at 0700 h the following morning, The results were co mpared with those of a 26 h ABPM performed in Italy the week before du ring which they slept from 2300 h to 0700 h. Results During the flight blood pressure and heart rate did not change compared with values dur ing the corresponding time interval of the control day. After the land ing, during the New York afternoon and evening (corresponding to the I talian sleeping time), blood pressure and heart rate remained unchange d, whereas during the night they decreased significantly, although the ir drop was less pronounced than that during the control day. Conclusi on The results of this study indicate that the decrease in blood press ure during sleep is the result of sleep itself rather than of the actu al time of day. (C) Rapid Science Publishers.