I've been learning TI for over a year. My technique has improved since. However I often felt breathlessness sometime even after 2 lengths. I found breathing every cycle helped, but only to a certain point, and it did not give the same relaxed feeling as breathing bilaterally. I was exhaling evenly until the next breath.
Today I saw in another thread Terry's advice on correct breathing.
The correct advice -- for breathing -- is:
1) Maintain a continuous flow of air into and out of your lungs.
2) Begin exhaling, in an unforced way, as soon as you finish inhaling. (This can be from both mouth and nose.) The rate of exhale will increase naturally as your tempo and/or exertion do.
3) Then exhale forcefully just as your mouth reaches the surface.
The proportion is often characterized as 20/80 - with the 80 percent coming just as your mouth clears. Is that exact? Who knows, but it gives you a graphic sense of how forceful the last bit may be.
It worked for me beautifully! The result was immerdiate as I no longer felt breathlessness even after 500 yds. Every breath was so refreshing. I think the reason is that by forcefully exhaling just before inhaling, your inhaling becomes more effective (but take no more effort) and can get more air into lungs. Inhaling is automatic. Previously I had to make effort to inhale but got less air.
This is like another focal point. I need to practice and practice to make it natural. Currently if I think about other focal points, I tend to foget to breathe this way.
Good luck everybody on breathing!