Disruption of Biological Rhythms Flashcards
AO1 (1) Shift Work + Shift Lag
Night workers required to be alert at night + so must sleep during day, opposite of natural available cues from zeitgebers
AO1 (1) SW + SL Sleep Deprivation
Sleep Deprivation - sleep problems during day because interruptions e.g. noises outside + daylight reduces sleep quality, 1-2 hours shorter than nocturnal sleep, REM particularly effected thus poor quality sleep - harder to stay awake at night especially through circadian trough
AO1 (1) SW + SL Decreased Alertness
Boivin et al. 1996 circadian ‘trough’ of decreased alertness during shifts - occurs between midnight when cortisol is lowest + 4am when fire body temp is lowest
AO1 (1) SW + SL Effects on Health
Significant relationship between shift work + organ disease, Knutsson et al. 1986 if work SW more than 15 yrs 3x more likely to develop heart diseases, Martino et al. 2008 link SW to range of organ diseases inc kidney disease - may be due to direct effects of desynchronisation or indirect e.g. sleep disruption
AO1 (2) Jet Travel + Jet Lag
‘Jet Lag’ used to refer to physiological effects of disrupted circadian rhythms - not equipped to cope with sudden + large changes, estimated dorsal portion of SCN takes several cycles to fully resynchronise to abrupt large changes in env. time, Winter et al. 2008 equivalent to one day to adjust to each hour change, symptoms = loss of appetite, nausea, fatigue, disorientation, insomnia + mild depression
AO1 (2) JT + JL - Performance Decrement
American baseball teams demonstrate debilitating effects of JL - travel from coast to coast to play - west 3 hours behind east, east > west = phase delay, west > east = phase advance, Recht et al. 1995 analysed US baseball results over 3 year period, east > west won on avg. 44% whereas west > east won on avg. 37%
AO2 (1) Alternative Explanation - effects of SW not just due to disruption of biological rhythms
E: Soloman 1993 difficult to meet friends/family when SW, divorce rates high - 60% among night shift workers, E: suggests social factors also contributing to disruption as well as bio, L: Therefore when trying to overcome harmful effects pf SW also important to implement strategies that reduce harmful effects of factors - more days off etc.
AO2 (2) JL may also be affected by factors other than disruption of biological rhythms
E: e.g. individual may sleep badly night before travelling because of worry, travel itself is tiring + many holidays involve hours getting to airport before flying, drinking alcohol or coffee, consistent noise + low oxygen cabin air can be cumulative factors, E: suggests must also consider social factors when looking at JL, L: Therefore in trying to overcome harmful effects, may avoid rest breaks to avoid this
AO2 Lab experiments shouldn’t be only method used to research effects of SW + JL
E: Boivin + James 2002 intermittent bright lights in field study of nurses which confirmed effectiveness of bright lighting to promote circadian adaption, E: Suggests important to conduct field experiments as well to confirm findings as investigate whether same ‘laws’ apply in everyday life, L: Therefore combination of field + lab would produce more reliable + valid findings
