A lot of fitness advice is geared towards the safety/efficiency frontier—i.e. how to improve your fitness quickly but without too much injury risk. However, I’m personally equally interested in the comfort frontier. For example, if it’ll take me 3x longer to reach the same vo2 max by only ever running at <=70% of my max heart rate, I may still prefer that because it’s so much more pleasant to run at that exertion level.
A lot of fitness advice is geared towards the safety/efficiency frontier—i.e. how to improve your fitness quickly but without too much injury risk. However, I’m personally equally interested in the comfort frontier. For example, if it’ll take me 3x longer to reach the same vo2 max by only ever running at <=70% of my max heart rate, I may still prefer that because it’s so much more pleasant to run at that exertion level.