Bowling Green State University conducted a study recently that shows that women work harder at the gym than men do, from a cardiovascular point of view, while they are doing high intensity training. The University of Alabama and the University of South Carolina joined in the study as well.
An experiment was done in Norway, in 2004, that took men and had them do interval training. They ran different four minute intervals, one with one minute of rest, one with two minutes, and one with three minutes of rest. During the study, the researchers took the idea from this experiment but instead they asked eight men and eight women to do the interval training. They told the participants to run as hard as they could during these intervals.
During this study, the women on average, did not run as fast as the men did but they had a higher maximum heart rate percentage and a higher maximum oxygen intake rate as well. This means that while women may not run as fast as men when doing interval training, their lungs and heart work harder. This also may also mean that women may recover from the exertion faster than men. This is just a theory at this point and more research is need to study the recovery times.
Try using the findings of this study during your interval workouts and see how much it can help you. Run at a 2:1 work to rest ratio. For example if you run for four minutes, take two minutes to recover before you begin to run again. Also remember that if your workout feels like it is hard, you are doing things right, but trust your body and make sure that you are not pushing yourself too far.