Česky
One Canadian study monitored sleep in a small group of police officers who worked night shifts. Sleep time and timing, light levels and the amount of the "sleep hormone" melatonin produced were monitored. Normally, melatonin is released late in the evening when we start to feel tired and get ready for bed. However, if you are adapted to night shifts, the peak of melatonin production shifts to the daytime hours. Those police officers whose bodies were able to adapt to night shifts (and there were only 40% of them) felt better and were more alert at work. Similar results were shown in a larger study, this time of 3,000 police officers, where an additional 40% were diagnosed with a sleep disorder.
If we focus on the physiological effects, then we must mention the increased levels of the stress hormone cortisol, which in the long term leads to a higher risk of heart complications and higher blood pressure. It has even been shown that just one single night shift is enough to raise blood pressure. Other long-term effects include impaired glucose tolerance and metabolic changes even leading to an increased risk of developing type 2 diabetes and obesity.
And if we have no choice but to work at night, then we have no choice but to focus on other aspects of a healthy lifestyle to balance the situation, namely a rational and healthy diet and adequate physical exercise. When sleeping during the day, it is also advisable to sleep in a well-darkened and ventilated room.
