Hm, maybe its not really anything about your body changing, but your perception of it having changed. Concentrate on your belly button, for example. Normally, we dont really consciously feel the pulse there, but if you concentrate on it long enough, it will feel really strong. Its there all the time, but we only notice it, if we actively look for it.
Fair enough. I am and have been meditating and doing breathwork. I will continue. Any hypothesis on why the first occurrence happened in the first place?