Th. Monk et al., REGULARITY OF DAILY-LIFE IN RELATION TO PERSONALITY, AGE, GENDER, SLEEP QUALITY AND CIRCADIAN-RHYTHMS, Journal of sleep research, 3(4), 1994, pp. 196-205
A diary-like instrument to measure lifestyle regularity (the 'Social R
hythm Metric' CRM) was given to 96 subjects (48 women, 48 men), 39 of
whom repeated the study after at least one year, with additional objec
tive measures of rest/activity. Lifestyle regularity as measured by th
e SRM related to age, morningness, subjective sleep quality and time-o
f-day variations in alertness, but not to gender, extroversion or neur
oticism. Statistically significant test-retest correlations of about 0
.4 emerged for SRM scores over the 12-30 month delay. Diary-based esti
mates of bedtime and waketime appeared fairly reliable. In a further s
tudy of healthy young men, 4 high SRM scorers ('regular') had a deeper
nocturnal body temperature trough than 5 low SRM scorers ('irregular'
), suggesting a better functioning circadian system in the 'regular' g
roup.