What are guidelines for a “seasoned citizen” in terms of:
Warm-up time period
“Normal” aerobic time interval (aerobic capacity rate - i.e. 80%)
Intense aerobic time interval ( >90%)
I have been warming up for 10 minutes, but I might shorten that and see what I think.
As to interval lengths time wise, the old Tabata rule was 20 intense, 10 seconds normal.
But that has been changing.
I found the 20/10 routine kept the overall workout too short for my liking (I like at least 30 minutes total).
I do a 30 sec intense (wide open--HR above 160) followed by 2 minutes normal (HR initally at 135-ish and later in the session 145-150). I think you can mix and match the interval periods to see what works best for you. And I would define what works best as that which gives you the best results AND what is the most fun. If it ain't fun, you probably won't keep doing it. I really like the routine I am using at present because it feels so damn good.
I sometimes use the last 5 minutes of the session to row at a normal pace with a HR of 150-155 (as sort of a cool down).
The fun thing about this kind of work out is that you are so busy keeping track of the time that it is over before you know it.