Night owls and graveyard shift workers take note—a Canadian study “Circadian Adaptation to Night Shift Work Influences Sleep, Performance, Mood and the Autonomic Modulation of the Heart” monitoring the timing of sleep, light levels, and the quantity of the sleep found that melatonin levels can occasionally adjust for the better. Claudia Hammond in a report for the BBC writes that “usually we release melatonin late in the evening when we start feeling tired and ready for bed. If you’ve adapted well to working nights, the peak will move to daytime instead,”
In this study, those whose pattern of melatonin production showed they had made that adjustment felt happier and more alert, as well as showing faster reaction times – but only 40% managed to make the switch. In a larger study of more than 3,000 police officers working shifts in Canada and the US, the consequences for those who were unable to adjust were clear, with 40% diagnosed with some kind of sleep disorder.
“Even if you do feel OK, there’s also the question of whether your body could be suffering in the long-term,” writes Hammond. “When it comes to assessing the physiological effects, one of the problems is differentiating between the impact that shift work might have on your lifestyle from the direct impact of working during the night. It is harder to eat healthily or to exercise regularly if you’re working shifts. Not only is a salad harder to obtain during the night, but it’s probably not what you feel like when you’re trying to keep yourself awake. This tempts people towards snacks and takeaways.”