You found this great piece of information from mercola.com. Obviously the best way to really get a cardio workout is to have short high intensity peaks in your workout to really push yourself.
New findings show that it pays to switch short bursts of high intensity exercise with mild recovery during treatments at least once a week.
Using Interval Training
Although this alternate technique, called intercourse workout, has been around for decades, a new study has confirmed that it can dramatically improve cardiovascular fitness and fat burning capabilities in the body.
The researchers asked eight men and women of college age to return for 30 seconds and then either stop or fly gently for four minutes. Just two weeks of this training, 75 percent doubled their stamina.
A control group, which did not perform any training at intervals, did not show any improvement in endurance. The remarkable improvement of the training group with intervals was even more surprising, as volunteers were already quite fit.
Another study also showed that training from time to time enhances the body's ability to burn fat. Eight women in the early 20's had been told to go for 10 sets of four minutes of hard riding, followed by two minutes of rest. After two weeks, the amount of smoke burned in an hour of moderate cycling increased by 36% and their cardiovascular capacity improved by 13%.