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I just started learning to swim a few months back. From barely being able to float for a few seconds, I am now able to swim along an entire length (25m). However there are two caveats: 1) I almost always use a hand paddle - my bare hands never catch as much water efficiently. 2) even with a paddle, I am breathless after 25m. Making another 25m seems an uphill task for the next few minutes.
Moreover, I am unable to continue any further. My body is restless and my heart beats faster during my next 25m; consequently somewhere midway to three-fourths along the pool, I lose my balance and from thereon, start walking to the near end.
While I would love to believe I shall improve and this too shall pass, this has been going on for more than a few months. I have incorporated a lot of Internet advice: go slow, relax, more water displaced per stroke, look 45 degrees ahead in water, focus on hips for kicking, rotate well. While they all have helped me improve to some extent, the core issue of breathlessness persists. Is this to do with my lung capacity and stamina?
Is there anything I can do to get better?
PS: I have zero difficulty with backstroke; with breaststroke I am comfortable for up to 50m. My knees start aching after that, but there are no breath issues.