disruption

• JET LAG

  travelling between time zones can cause phase advance whereby person struggles to wake due to being in a circadian trough.

  alternatively, person can also be in a phase delay whereby they sleep at later times

  this causes jet lag due to desynchronisation of biological rhythms

  to entrain rhythms to fit with time zones they can accustom to social cues whereby they eat/sleep at the same time as the rest of the population
• shift work disorder (SWD) is when people are unable to adjust their body clock to new working hours which leads to insomnia or excessive daytime sleepiness.
• shift work - causes disruption to biological rhythms as people sleep in the day and are working in the night which is the reverse of natural sleep/wake rhythms and is not in line with exogenous zeitgeber. this can decrease levels of alertness as people are working during circadian trough where cortisol and body temperature levels are at their lowest which poses threats to job performance and individuals wellbeing. can also make it difficult to sleep as exogenous zeitgebers present at day time (noise and light) can disturb scn's ability to produce melatonin.