Sleeping and Eating Cycles of Taxi Drivers Working a 24-Hour Shift

Abstract

Many taxi drivers in Japanese large cities work 24 hours at a time on a 1 day-on 1-days off 48-hour work cycle. The working shift lasts from morning of the first day to early dawn of the second day. We investigated the schedule of eating, slepping and alcohol intake over this twoday period for 287 taxi drivers (mean age,48.1) working for companies in Osaka Prefecture. The peak meal times on the first day were 6: 00,12: 00 and 20: 00, and 12: 00 and 19: 00 on the second day, but there was no peak on the morning of the second day. Subjects were divided into 5 groups depending on the time they start taxi-driving. When these groups were compared, meal times on the first day differed, but we found no difference in noon and evening meals on the second day. Mean value of total length of sleeping time over the 48-hour period was 13.6hour, of which 37.5% occurred during the day of the second 24-hour period. Sleeping periods during the second day were interrupted or ended by meals. On the second day,73.9% of the drivers consumed alcoholic beverages. The number of drivers consuming alcohol several times on the second day was higher than that of drivers consuming alcohol only once, and 13.5% of drivers consumed alcohol three times or more. Alcohol was consumed most frequently after 17: 00 on the second day, followed by the time periods 0-11: 00. We concluded as follows; 1)meal intake of the taxi drivers on the first day followed a normal pattern based on the time they start taxi-driving; 2) from directly after getting off work until the middle of the second morning, there was no fixed pattern; 3) sleep was interrupted in the afternoon of the second day and normal pattern was forcibly re-established.