The only "real" sport that I can watch on TV is motocross racing, proven years ago and ranked as the most physically demanding sport on the planet. All the other sports have continuous breaks, time outs, built in. The 45 minute motos are brutal, and there are no mental breaks anywhere, lose concentration, and you get paralyzed or lose your life.
But now we have Ironman Triathlons, and that has to be worse.