It’s now widely recognised of the effects of acute sleep loss on cognitive performance. Comparisons between sustained wakefulness (i.e. acute sleep loss) and blood alcohol impairment have been made, finding simple reaction time are impaired to similar degrees after around the 20 h mark (see below from Maruff et al. 2005 – source in links).
However, 20-24 h+ of sustained wakefulness is pretty extreme (but still not uncommon for some people coming off night shifts back to other swings).
What about the effects of chronic sleep restriction – that is, slightly fewer hours per night over a longer period? The below data highlights how rapidly cognitive performance (reaction time) drops off with differing times in bed.
It was found that cognitive performance stabilised when people achieved 9 hours of sleep per night. However, when sleep was reduced to 7, 5 and 3 hours of sleep per night, it was found that cognitive performance was impaired in a dose-response manner with the greatest performance loss with 3 hours per night – see below.
Note that greater performance losses with lower mean speeds indicates far greater performance losses.
On the X axis, B = baseline sleep (no intervention), E1-7 = experimental intervention sleep restriction protocol and R = recovery nights (sleep back to normal, e.g. 8 hr a night).
Interestingly, even after 3 nights of recovery at “normal” sleep levels following mild to moderate sleep restriction, performance was not restored back to baseline levels.
Similar to what others have argued, catching up on sleep on the weekend following mild to moderate chronic sleep restriction may not be possible or achievable, and this has further implications for shift workers.
Source image 1: https://doi.org/10.1111/j.1365-2869.2004.00438.x
Source image 2: https://doi.org/10.1046/j.1365-2869.2003.00337.x
Link to the LinkedIn post: https://www.linkedin.com/posts/benhutchinson2_how-hazardous-is-sleep-loss-for-safety-comparable-activity-6917253256897318912-DNJj?utm_source=linkedin_share&utm_medium=member_desktop_web
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