After surgery, I found that I had increased energy and stamina (the ability to perform physical labor). Over the years I had become flabby and overweight, but now I was fit and lean. Exercise is good, but sometimes one can overdo the exercise and cause harm.

Rhabdomyolysis, or rhabdo for short, occurs when muscle damage is done after trying to lift too much weight, or lifting with such frequent repetition that it prevents the taxed muscles from resting. When this happens muscle fibers break down and die. These fibers then enter the bloodstream and can create kidney problems, and in some cases, kidney failure. Some severe cases may require kidney dialysis.

How do you know whether you're in danger of being afflicted by rhabdo? There are symptoms to watch for, but since they aren't specific to this condition it's hard to tell whether a specific weight-training workout, or an intense stationary bike-riding session, is the culprit. In addition to obvious muscle weakness, other symptoms include: nausea; fever; feeling of sickness; bruising; lack of urine output and/or dark-colored urine; fatigue and vomiting.

The best prevention is exercising common sense. Don't overexert. Hydrate by drinking water during your workout. And as soon as you begin feeling prolonged muscle fatigue or more than 30 seconds or so, stop what you're doing. And rest.

https://www.acsh.org/news/2018/02/27/kidney-damage-can-occur-overly-intense-muscle-use-12634

Just to clarify while Rhabdomyolysis may be something you should look out for this is not a common occurrence for people who don't have a genetic predisposition. The most common reason why this occurs with people who don't have the predisposition is that they don't adequately hydrate themselves and don't give their muscles time to recover.

Pushing your muscles to exhaustion is the only way you build muscle (by literally tearing them and forcing them to repair themselves).

I nearly pushed myself to rhambo a few weeks ago and got overtraining syndrome for a few days. I did 3 back to back HIIT workouts. Be careful everyone. I’ll never do it again. My limit is 2 a day now.