Mouse Idle And The Fatigue Tells Nobody Talks About
Most fatigue tracking ignores the mouse entirely. Idle stretches and movement cadence are quieter than camera signals but harder to game, and they line up with the rest of the read.
The signal nobody talks about
Mouse activity gets a lot less attention than keyboard or camera signals in productivity tracking. Part of that is fashion; part is that mouse data alone is not very interpretive. As a confirmation layer for the rest, it is one of the more useful inputs Sarenica has.
Mouse distance and speed
Sarenica records cumulative mouse distance and average speed per minute. They both move with task type more than strain. A design block has very different mouse metrics from a reading block, even on the same day.
Where they get useful is comparing comparable blocks against each other. If your morning design sessions usually average 700 px/sec and your afternoon design sessions average 480 px/sec, that is a real signal — same task, different cadence.
Idle stretches as fatigue tells
The mouse signal that earns its keep is idle minutes — stretches longer than about 30 seconds with no movement at all. They are not the same as breaks (you may be reading or thinking), but they accumulate in a pattern that tracks closely with session length.
Short sessions accumulate almost no idle time. Long sessions accumulate a lot, and the rate accelerates in the last third. That shape is a useful confirmation of what fatigue and focus signals already suggest.
Click rate vs movement
Click rate often diverges from movement rate. A lot of clicks with little movement is a navigation-heavy task. Lots of movement and few clicks is a passive consumption pattern. Each shows up differently in fatigue burden.
The pattern that comes closest to a strain signal is high movement with declining click rate within the same session — your hand is still moving but you are doing less with each click.
Where it pairs with eye signals
Mouse data on its own is rarely conclusive. It earns its place in the weekly report by lining up with the camera signals. When eyes-closed seconds, head-pose drift, and mouse idle all rise together in the same session, the weekly report has a much stronger claim than any of them alone.
That is also why Sarenica does not call fatigue from mouse data on its own — the signal is too noisy out of context, and the cost of a false positive is wrecked trust in the rest of the read.