Melatonin synthesis: A possible indicator of intolerance to shiftwork
Article first published online: 15 OCT 2002
Copyright © 2002 Wiley-Liss, Inc.
American Journal of Industrial Medicine
Volume 42, Issue 5, pages 427–436, November 2002
How to Cite
Griefahn, B., Künemund, C., Golka, K., Thier, R. and Degen, G. (2002), Melatonin synthesis: A possible indicator of intolerance to shiftwork. Am. J. Ind. Med., 42: 427–436. doi: 10.1002/ajim.10122
- Issue published online: 15 OCT 2002
- Article first published online: 15 OCT 2002
- Manuscript Accepted: 25 JUN 2002
- salivary melatonin concentrations;
- rectal temperature;
- diurnal type;
- shift work;
- constant routine
Melatonin synthesis, which is directly controlled by the central circadian pacemaker indicates the circadian phase better than rectal temperature.
Thirty four men (16–32 years, 7 morning, 13 neither, 14 evening types) performed a constant routine (24–26-hr bedrest, < 30 lux, 18–20°C, hourly isocaloric diet). Salivary melatonin level was determined hourly and rectal temperature was continuously recorded.
The nadir of rectal temperature occurred 1.5 hr (P = 0.017), the onset of melatonin synthesis 3 hr earlier (P < 0.0001) in morning than in evening types. Morningness was not related to the quantitative but significantly to the temporal parameters, closer to those of melatonin than of rectal temperature.
The melatonin onset is a more reliable indicator of the diurnal type than the nadir of rectal temperature. As morningness has been associated with intolerance to shiftwork, melatonin profiling provides a suitable basis for the establishment of directed preventive measures. Am. J. Ind. Med. 42:427–436, 2002. © 2002 Wiley-Liss, Inc.