Time flies when you're having fun—or when you're pushing your cardio limits. Each of these sprints requires only 30 seconds of max effort and is followed by a full minute of rest, so don't slouch.
If you feel up to it, add another series to your cardio work today. Yes, it's a lot of work, but your body and mind are more than ready to take on greater challenges. These greater challenges will lead to increased adaptation and continuing gains.