Biological Rhythms 2

Outline shift work and it's impacts

• Disruption of biological rhythms either causes phase delay which lengthens the day and is what our body prefers or phase advance which shortens the day.
• Shift work has various negative effects on the individual these are: 1. poor reasoning 2.impaired reaction time 3. decreased alertness between midnight when cortisol levels are lowest and 4am when temperature is lowest and 4. fatigue. 
• Because shift workers have disturbed sleep during the night they often have to sleep during the day which causes their biological rhythms to become disrupted.
• Knuttson found that those workers who had done shift work for 15 or more years are 3 times more likely to get heart disease. 

Outline jet lag and it's effects 

• Jetlag occurs when we travel accross time zones.
• Phase delay occurs when we travel from east to west.
• Phase advance occurs when we travel from west to east.
• This can cause 1. insomnia 2. nausea 3. disorientation and 4. performance decrement
• But obviously this is subject to individual differences as if you are used to flying you may not suffer this effects as much and if you are tired from travelling already the impact of these effects may be increased.

Outline the lifespan changes for sleep

• Babies have 16 hours sleep but their cycles are shorter as they wake every one hour and they also have more REM sleep.
• Children have 9 hours sleep, have 30% REM sleep and are more likely to suffer from sleep parasomnias such as sleep walking.
• Adolescents have 9-10 hours sleep and are likely to suffer from phase delay as they are more inclined to stay up late and wake up later in the morning.
• Adults have 8 hours sleep, 25% of which is REM sleep and are more likely to suffer from sleep apnoea and insomnia.
• Old aged people have 8 hours sleep also but only have 20% REM sleep and have more Slow wave sleep. They are also likely to suffer from phase advance as they nap frequently.