Originally Posted by
StanSeven
There are more than one type of intervals. Sprint repeats are similar to what many call "red-line" intervals. They are performed at 90-100% of your maximum heart rate. Most people think of intervals as anaerobic zone (80-80%) are performed for 15 -30 minutes
Thanks- I hadn't heard that distinction. While there are indeed many, many ways to approach interval training, I've always considered the bout to be in the red line, at least in those who have been pursuing HIIT long enough to be considered "conditioned." I'm pretty sure that most people consider intervals that way as well.