Disruption of Biological Rhythms

When there is a desynchronisation of oscillators, there is the resulting consequence of disruption to these biological rhythms. The most common examples are known as "shift lag" and "jet lag".

(AO1) Shift workers (who must be alert during the night) tend to sleep during day time, which is the opposite of our natural rhythms, thus out of line from most of the available cues from zeitgebers. There are several negative effects of shift work, known as shift lag. Decreased alertness, for example; according to BOIVIN, shift workers are likely to suffer a trough of decreased alertness when cortisol levels and the body temperature are at their lowest (from 12am to 4am). As well as this decreased alertness, shift workers also tend to suffer from sleep deprivation. This sleep deprivation is due to the fact that they are required to sleep during the day, when the outside world is at work, thus resulting in distractions and interruptions (noise, for example). As they are sleeping during the day, they are also going to feel the reduction of sleep quality that is caused by the exposure to daylight. Daytime sleep tends to be between one and two hours shorter than nocturnal sleep, and REM is typically affected as well (TILLEY AND WILKINSON). As a consequence, shift workers find it harder to stay awake, especially through the alertness trough mentioned before. Whilst alertness and sleep quality is affected, there are also effects on the health of shift-workers. According to KNUTSSON, individuals who worked shifts for over fifteen years had a three times increase on the likelihood of developing heart disease when compared to a non-shift worker. This may be due to the effects of resynchronisation or indirect effects.

(AO1) As our biological systems are not well adapted to cope with sudden and large changes in environmental time, our dorsal sector of the SCN takes several cycles to fully resynchronize itself, ergo resulting in jet lag; the resulting consequence of a disruption to circadian rhythms (it need not be jet travel). Symptoms of jet lag include nausea, a loss of appetite, fatigue and insomnia…