The boiling frog story provides good insight into the practical reality of achieving a high level of performance (physical or mental). The point of the story is that gradually upping the intensity over time allows your body and mind to get used to the discomfort of it, without breaking you.
When I started judo two years ago, I would train 3 times a week and felt like it was a lot. I would dread doing randori (sparring) for longer than 5 minutes. The same was the case when I started BJJ a year ago. I couldn’t do more than one 5 minute set of live training without feeling like I’ve just been run over by a bus. My training partners were good, but they weren’t gunning after submissions or throws like their life dependent on it. Even still, it was exceptionally challenging for me (mentally and physically).
Fast forward to today. I’m training twice a day on most days, and I’m often doing sets of live training for 30-60 minutes with little rest in-between. And many of the people I face are animals (in the best sense of that word), both in skill and intensity. But I’ve somehow become comfortable doing all that: the frog in boiling water.
That said, I am always looking to leave the comfort zone, and have been recently lucky to meet a few individuals who it seems don’t know how not to constantly push the pace. With instructors and training partners like that, I can’t help but to get better.