The Natural World

The natural world is dominated by cycles that are constant and repeated – the moon’s rotation around the earth, the changing of the seasons, the changes between night and day. It is these cycles or rhythms that in part control changes in our metabolism, mood and behaviour, and even the patterns of our sleep. The circadian rhythm is the cycle that indicates when to be awake and when to be asleep. This is a daily cycle that is controlled by changes in amplitude (highs and lows) of light and temperature. As day turns to night, the sun sets and it becomes cooler. The triggers of less light and lower temperatures signal to the body that it is time to slow and begin the pattern of sleep. Of course, there may be many hours between sunset and the time people actually go to bed, but it is from this time that we generally become increasingly less alert and reaction times can be noticeably slower. There are a number of factors that can affect our circadian rhythm. Working night shifts, which requires people to act in contradiction to the body’s natural rhythm, is perhaps the most damaging. Despite getting a good 8 hours sleep during the day, night shift workers still tend to feel drowsy for at least some of the night. This is the main factor for the increase in workplace accidents on this shift when compared to the day shift. The seasons can also affect our natural rhythm, with people having less energy during winter months when there is less sunlight and warmth to stimulate the brain. International travel, notably when travelling in excess of 4 hours, can also have a significant…