Originally Posted by
LGHT
Sadly 165 is my Z4 limit and my cardiologist said I should be careful and try to not push beyond that. Looking back at a few rides my last tough ride had me in Zone 4 for about 30 min of a 2 hour ride I don't recall the length of time I was in that zone at once, but I can recall it being at least 5 minutes of the 10 min tough climb.
I slowed down because once my HR got to 160 I didn't have much left and still had a lot of riding to do. The only good thing about riding those big hills is passing up the little electric cars as I hit 45-50mph on the way down!! The kids face in the back as I went by them was priceless!!
Well, if that's what he said, that's what you gotta do. Which, as HP points out, doesn't mean you can't go after it in Z4. Anything from 148 on up will make a big difference. You really want 157 and up for your 15 minute intervals. Start by just trying to do one interval. And don't worry about the rest of the ride. You'll do it too, just a little slower because of the interval. Starting out, I'd go 15' on, then 15' moderate work level, then another 15' interval. Work up to 3 of those, once a week.