Looking for some direction
I've been swimming at my local pool in SE Michigan 3-5 times a week for up to 45 min per session. I started in November 2017 with a total 500 yrd session. After getting close to giving up for the 20th time, I discovered TI and it has really helped me to swim longer and with greater enjoyment.
This past weekend I did a 1.2 mile open water race in 48 min (I suspect there was a lot of back and forth making this a 1.5 mile since I couldn't see without my glasses!). Leading up to the race I'd been doing a single 2300 yr set in about 42 min. I was doing this long set every time in the pool for the past month because I wanted to prove to myself that I could do the length. It also gave me a single set that I could compare day-to-day to see if I was progressing. I figured out that I could increase my average stroke rate from 1.57 seconds per stroke to 1.42 sps (as measured on my vivoactive3 watch) and my SPL would be close to 18 (25 yrd pool, I'm 6 ft tall, and 42 yrs old). As I increased my stroke rate, I increasingly felt like I couldn't keep up with the breathing and I would feel pretty uncomfortable and panicky. When this happens, I try to relax, reduce my stroke rate and glide more. Looking at the stroke rate and SPL and 100 time, I could see them sliding as I went along. My first 500 would have a 1:43/100 and I would end near 2:00/100 averaged over the full distance. Again, all these numbers are taken from my watch.
Now that the race is over and I've proven to myself that I can do the distance, I would really like to go back and really focus on improving. When I use a TT to do a long set at 1:30 I get the panicky feeling after doing 100 or 200 yards. This morning I tried doing the TT ladder starting at 1.40, going up to 1.75 by 0.05 secs and then down to 1.10. I started at about 17 SPL then got to 14 or 15 SPL and then by the time I got down to 1.10 I was up to 18 SPL. I then did a 100 at 1.20, 1.30, and 1.40. I felt like the 1.40 was my comfort zone and put me at around 15 SPL.
I'm wondering whether anyone might have suggestions on what type of workout you'd suggest to help me to improve my stroke rate without feeling the panicked feeling while also being able to sustain it over distance. I'm limited to 45-minute sessions and I really like being able to go to the pool. I really appreciate the attitude of constant improvement adopted by the TI community and would be grateful for any feedback people can offer. Thanks!