Flashcards in Disruption of Biological rhythms Deck (12)
Night workers often experience a trough of decreased alertness during their shifts, this occurs between 12am-4am when cortisol and temperature is lowest.
Workers who sleep during the day may experience sleep deprivation due to interruptions during the day. Day time sleep is reduced by 1-2 hours and REM is particularly affected. Making staying awake at night all the more harder
Effects on health
It has been found that individuals who worked shifts for more than 15yrs are 3 times more likely to develop heart disease. Due to the effects of desynchronisation, shift work has been linked to a range of organ diseases.
Shift work effects not just due to the disruption of biological rhythms.
The effects may be due to lack of sleep associated with going to sleep an unusual times.
Social disruption is a factor too, meeting and socialising is difficult,divorce rates may be as high as 60% among those as night-shift workers.
Non-fluctuating shifts are less disruptive because you can get used to one sleep-wake cycle. More problems occur in those who partake in fluctuating shifts
Are forward rotating shifts better?
Yes, they are better for the health of shift workers. An example of this is morning for 1 week, afternoon the next and night the next. Rotating workers through shift changed more quickly is better for health.
It is estimated that the dorsal portion of the SCN takes several cycles to fully synchronise. This is equivalent to one day to adjust to each hour of time change.
American baseball teams when they have to travel from East to West (phase delay) play better than those who have to travel from West to East (phase advance) showing that phase advance has a greater influence on performance.
What else may jet lag be affected by?
Sleeping badly the night before travelling, travelling itself and holidays involving drinking alcohol or coffee, noise, annoying passengers can all contribute to jet lag.
Eating on the new time schedule can help entrain biological rhythms because our body clocks are reset by food intake.
It was found that those who gave up shift work tended to have rhythms that changed a lot while those who were 'happy shift-workers' had unchanging rhythms.