Originally Posted by eduskator

1) Short answer is: it depends. Staying close to your LT1 for an extended period of time is beneficial. The longer the duration, the better it is in terms of endurance gain. How many hours per week do you train? If you don't train a lot, I wouldn't bother trying to stay close to your LT1. In fact, I would favor intervals if I would train a low amount of hours (5h, for instance) as it's proven to be more beneficial for the health and cardiovascular fitness than only doing endurance paced workouts. If you're training a lot, then yes it's important to stay in certain zones for a certain time (IE, 80% LT1, 20% LT2 / VO2max). On my end, I aim for 80% LT1, 10% LT2 and 10% VO2max.

2) According to experts, you should stay in that zone 100% of the time if you want to maximize gains in terms of mythocondria, hence why it is nearly impossible when riding outside. You will go above it when climbing and below it when descending and/or when stopping at traffic lights, etc. Best way to do this IMO is to use a training with erg mode and track your HR. Don't rely on Strava's zone indicator as it shows the total time spent in zones, not the continuous.