> Are you doing interval training in your swimming? I think how you train can have a big impact on your VO2MAX improvement vs. time invested. That said long dis

> Are you doing interval training in your swimming? I think how you train can have a big impact on your VO2MAX improvement vs. time invested. That said long distance running does require a lot of time investment. I'm not sure if you can get to run a marathon by running an hour a week but I expect that answer is no. What had the biggest impact on RHR was when I was just swimming 1km per session at normal pace (it took me about 25 mins, I'm a beginner). RHR dropped week over week down to 42. When I got a coach he had me do mostly interval training and interestingly my RHR crept higher although I did improve in terms of speed. Past month I've been lazier and training again to swim continuously and I see my RHR decreasing again. Unsure about the science of it and whether it applies to others. I don't think RHR is necessarily a marker for fitness but I thought it was interesting that pretty significant change was happening although I was maybe swimming 30 mins a couple of times a week.