Quiz 5 Study Guide- Human Factors

What is fatigue?

A complex state causing cognitive impairment as the result of the combined effect of sleep/wake history (time awake), circadian phase, and time on task

What happens to you when you’re fatigued?

Neurobiological effects can begin and can only be returned to baseline with adequate sleep, 17 hours of wakefulness is cognitively equivalent to .05% BAC

What is circadian phase?

Time of day modulated core body temperature, sleep propensity, and performance in a sine wave shaped, approximately 24-hours

How does this rhythm work?

Set by light exposure and is mediated by the ganglion cells in the retina and the suprachiasmatic nucleus located in the brain

What are the highs and lows of Circadian rhythm?

Lowest: 0600 hrs

Highest: 1800 hrs

Sleep loss

Degrades performance in all areas from simple reaction time to complex tasks. higher mental functions like complex tasks are more affected than simple tasks

Where do cognitive functions take place?

Prefrontal cortex and parietal association areas

Sleep propensity follows what?

Core body temperature

Sleep, Activity, Fatigue, and Task Effectiveness (SAFT) / Fatigue Avoidance Scheduling Tool (FAST)

Offers a prediction of what performance will be, takes into account time awake and circadian rhythm but does not factor in time on task

What is time on task?

Progressive decrease of performance across the duration of a cognitive task, can be seen within a few minutes of starting the task for both rested and sleep deprived states, more pronounced while sleep deprived, can be reversed with a simple break from the task

There is only one way to prevent fatigue, what is it?

Sleep

What is sleep propensity?

Essentially a measure of how tired someone is at any given time