What exactly? I run 4 miles with my heart rate at 81% of max 3X week and play in the snow on Saturdays. The gains on those climbs average over 3,000' but the ascent distances are relatively short from 1.5 to 4 miles . It averages out to about 8 hours/week.
I judge my physical condition by average heart rate and the in the zone time. The rate is just above optimum for me and average times in the zone are between 35 and 40% of the total run, which for me is very good.
