18 minute swim - 6/15

Having just done a 1/2 mile swim on Saturday, with the approximate level of exertion relatively fresh in my mind as well as having some decent HR information, I thought I'd start trying to find some correlations with effort and speed in the endless pool vs a pool or open water. I knew without even trying that having the power setting at 40 would be too low. I also knew that 70 would be too much - as that is what my interval sessions are at. So I figured I'd split the difference, and start with 55.

Unfortunately, the endless pool has a tendency to drift and decrease over time. So, what I did was to set it to 60 in the beginning, figuring it would drift down to 55 after a few minutes.

So for this session, I just did an approximately equivalent amount of time as it took to do the 1/2 mile the other day - as I wanted to get some more exposure to swimming that kind of distance non stop.

Total Time: 18:37
Avg HR: 150
Power Setting (avg): 55

I found that after I finished up, the power setting had drifted down closer to 50 - so I'm estimating the average to have been 55. A few minutes after the start, I felt like the level of exertion was about similar to Saturday's swim - mildly uncomfortable, but definately sustainable. After probably 10-12 minutes, that went away and it became more a mental exercise. Just like running on a treadmill - I tend to get bored when there isn't something passing by (even turning at a wall every 50 yards does wonders for breaking the monotony). In retrospect, the physical exertion level probably felt like it decreased because it probably had - since the power setting drifted down to 50.

So in the end, with the avg HR of 150 vs 162 the other day, this was a decent start to getting a correlation. It's difficult because in a pool or open water, you have to propel yourself - whereas in an endless pool you just have to overcome friction. So the stroke cadence can be the same, but when propeling yourself more actual strength is required, which can drive up HR. I have a feeling that if I were to get a HR of 162 in the endless pool, it'd be at such a fast pace that it might be counter productive as it would be training my arms to swim at a pace that they'd be unable to maintain in a normal swim.