The faster the frequency of your brain the more Frames Per Second you can process hence the slower time gets. The opposite is true as your brain frequency slows and you grow weary time seems to speed up as you're processing less FPS i.e. there's a shorter distance in time (less frames) that gets traversed quicker.
The gist of it is, time is being relaxed with a lower brain frequency; you're getting slower but time remains constant.
Your brain is biological - there is no frequency like there is in computer processors.
