Adaptation of the 6-sulphatoxymelatonin rhythm in shiftworkers on offshore oil installations during a 2-week 12-h night shift

Neurosci Lett. 1998 Jan 23;241(1):9-12. doi: 10.1016/s0304-3940(97)00965-8.


The circadian rhythms of most shiftworkers do not adapt to night shift. We have studied oil workers on a rotating system involving 2 weeks day shift (0600-1800 h) and 2 weeks night shift (1800-0600 h) throughout a day and night shift sequence. Urine samples were collected 3-hourly whilst awake, with an over-sleep collection, for the measurement of 6-sulphatoxymelatonin by radioimmunoassay. In three separate groups results showed adaptation by delay of the 6-sulphatoxymelatonin rhythm in the first week of night shift. The rates of phase shift (mean +/- SEM) were 1.51 +/- 0.16 h/day (n = 5), 1.32 +/- 0.41 h/day (n = 5) and 1.77 +/- 0.31 h/day (n = 17). Specific environmental and social factors together with the shift schedule on oil rigs may facilitate adaptation to a 12 h night shift within a week.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological*
  • Adult
  • Circadian Rhythm / physiology*
  • Fossil Fuels
  • Fuel Oils
  • Humans
  • Light
  • Male
  • Melatonin / analogs & derivatives*
  • Melatonin / urine
  • Middle Aged
  • Work Schedule Tolerance*


  • Fossil Fuels
  • Fuel Oils
  • 6-sulfatoxymelatonin
  • Melatonin