The SmartCap Fatigue Levels are presented on a numerical scale developed at the University of Queensland in 2004. This scale ranges from 1 to 5, with Level 1 representing a hyper alert state and Level 5 representing the involuntary sleep (including microsleep) state.
As with all scales, the numbers themselves are arbitrary; what matters is the meaning of each number, and how we use the information to proactively manage our fitness for work.
The extreme values of 1 & 5 are not incorporated into the SmartCap product for two reasons. Firstly, the independent validation study only used values 2 through 4; secondly, these values don’t provide information that directly assist the user in the real time management of fatigue.
The SmartCap Fatigue levels included in the product can be interpreted as follows:
Level 2: This is a normal level of alertness, where the SmartCap is not detecting any signs of a lowered ability to resist sleep.
Level 3: This is a normal level of alertness, where the SmartCap is detecting the first signs of a lowered ability to resist sleep.
Level 3+: Suspected impairment related to fatigue
Level 4: Significant impairment related to fatigue, associated with an increased risk of microsleep.
It’s important to note that a Level 4 does not mean a microsleep occurred, nor does it mean that a microsleep was imminent. A level 4 indicates an increased risk of microsleep. That risk is further heightened by a low stimulus environment, and is best reduced by operator action and activity.