Medicine isn't usually tied to activity. It's tied to "this leaves your bloodstream at X/hr. You need to replace it every Y hours". It's possible that it leaves your bloodstream at different rates depending on your activities, but I don't think doctors take that into account when prescribing medications.
With a more erratic schedule, "take this pill at 10am on Tuesday" is a more valuable reminder than with a regular schedule where you might take it triggered by a regular event.
With a more erratic schedule, "take this pill at 10am on Tuesday" is a more valuable reminder than with a regular schedule where you might take it triggered by a regular event.