Hi Steve,
Yes, our exercise model does allow examination of physiological variables in response to graded exercise. Pulse is a complete mechanistic model, so as exercise is occurring the engine is calculating the physiology of the entire body every time step (0.02s)
For example, here are a few outputs over time for our Exercise Stages Scenario
Our exercise model is documented here
Here is a post that may also help
Our exercise model does take into account blood gases and substance consumption and production (including lactate), but as any model, there are limitations and plenty of room for improvement and increased accuracy and fidelity.
Please take a look and let us know if you have questions.
We would love to further discuss any details you might be interested in.
Thanks!