You need to be a bit more specific; when you are in an anaerobic state your heart rate is pretty high trying to deliver more oxygen to your working muscles. If you are trying to train your anaerobic threshold, then, working at high heart rates is the best way to do it.
I guess my main question is, if you are more fit, will your heartrate be lower when you are working hard, or will your heartrate still be high, but you will be able to work at that state longer?
I guess my main question is, if you are more fit, will your heartrate be lower when you are working hard, or will your heartrate still be high, but you will be able to work at that state longer?
Both. At a lower level of exertion, your heart rate will not be taxed compared to non-fit persons. As you get to high levels of exertion, a fit person with high anaerobic tolerance will be able to tolerate the lactic acid buildup and go longer than a non-fit person, assuming that the fit person has the psyche as well.