Eye pupil dilation for attention analysis during exercise

It has long been known that the human pupil of the eye will dilate when a high level of attention is obtained. This can be used to measure if a person is actually paying attention when learning new tasks. Attention is known to correlate very closely to learning ability. In fact, it is crucial to learning.

However, measuring attention during exercise isn't a highly researched subject but could beneficial to measure, especially when learning new motor skills or patients re-learning old motor skills after injury.

Articles

Pupil Diameter Tracks Lapses of Attention (2016)
Pupillary dilation as a measure of attention: a quantitative system analysis(1993)
Pupil Size Tracks Attentional Performance In Attention-Deficit/Hyperactivity Disorder(2017)