I am doing HIIT running. I push myself to 85-90% of my maximum heart rate in the high intensity interval. In the rest phase, my heart rate usually stays high for a while, then quickly drops. I jog between the intervals. What is the optimal heart rate for the rest phase? Or in other words, what should be my heart rate when I start the next high intensity interval?
Your heart rate will stay quite high for a while after your high intensity interval, this is perfectly normal. The period of time it stays high will reduce as your fitness improves. When i do interval training I will be looking for my heart rate to settle back down to around 65-70% of maximum before starting another high intensity interval. Basically at the lower end of your aerobic zone. If I drop down any lower I find that i have effectively "warmed down" and too much of the high intensity interval is wasted getting my HR back up into the anaerobic zone.
Hopefully this makes sense?