Originally Posted by
hobkirk
Damn youngsters with your resilient muscles!
I'm 65, started riding in June, use a Garmin 705 w/ HRM, and I push myself quite hard (but certainly not dedicated racer hard). In 5,000 miles, the highest HR I've seen during rides is 155 (climbing). My max HR during several power intervals (3 minutes as hard as possible) was 151. My highest average HR for a ride was 141 with a 154 max (18 miles pushing hard the whole way). The 141 is 90% of my 155 max.
Does that translate into my LTHR is 141?
IMO, no. Very difficult to reach MHR. Certainly 3 minutes won't do it. 10-15 minutes on a trainer, going so hard that you have a friend standing by with a phone, might do it if you were well rested and had a good feel for your individual ramp-up. So don't worry about MHR. If you want to find LTHR, find a 20 minute climb and practice going as hard as possible up it. Your best steady state HR for the last half of it will be close to your LTHR, but only if you were well rested before the test. Easier to calculate a possible MHR from a known LTHR.
Even for a talented and experienced racer, it's very difficult to average LT over an 18 mile course.