To improve fitness, it is necessary to incorporate higher intensity interval training to provide a greater stimulus, as low-intensity training alone is insufficient for continued adaptation.

“so they're just basically not doing enough and so that points to the fact that if you want to get better you need to add in some higher intensity interval training obviously you can increase the dose of your moderate intensity training to your volume but adding a greater stimulus you know that seems to be the main benefit of doing high intensity training you can't just do the same thing you can't just do low intensity training all the time you need to not only mix it up for variety but you need to give your body a greater stimulus if you want it to adapt and improve”