Circadian rhythms of arterial pressure, heart rate and oral temperature in truck drivers.

Circadian rhythms of arterial pressure (AP), heart rate (HR) and oral temperature (OT) were studied in healthy male truck drivers and in a control group of air traffic controllers. Twenty-four-hour records of systolic and diastolic AP and HR and of OT were obtained from 12 truck drivers both during the outward and homeward journey in Europe and Asia, and from 12 air traffic controllers during a morning shift. Data were analyzed by the cosinor method. The results obtained in the control group were as follows (mesor/amplitude/acrophase): systolic AP (mm Hg): 111.1/6.1/16.51 h; diastolic AP: 68.4%5.6/16.58 h; HR (b.p.m.): 77.07/7.6/17.46 h; OT (dg C): 36.74/0.21/17.26 h. Statistically significant acrophase advances were observed for the circadian rhythms of systolic, diastolic and mean AP and of HR in TD during the outward journey in comparison with the control ATC group. These differences were still present during the homeward journey, in combination with an acrophase delay of the circadian rhythm of OT. Our results supply grounds to suppose that extended working time combined with greater load during a long-lasting trip may act to generate an internal desynchronization of circadian rhythms in long-haul truck drivers.