Possibly relevant: Chess might seem the least physically oriented of sports, not physical at all. But after about 40 years of age, it's hard to keep concentrating for hours - classical games often last 5 hours or more – and older players fade after the 3rd or 4th hour. One mistake and you're toast, often. See how none of the top players are over 40.[1] Two in the top 20 are over 40: Anand at 51 is world #17 – but in 2008 he was #1, and Topalov at 45 is world #19 – but was #1 in 2006. Experience doesn't seem to matter anything as much as youth! Also, the top players keep very physically fit, because they have to. It's no good winning for 5 hours if you then have a brain fade for 2 seconds. It's needs something like the stamina of a long-distance runner. It seems a top chess player can burn 6,000 calories – and lose 2 pounds – per day, playing in a tournament.[2]

[1] https://2700chess.com/

[2] https://www.cnbc.com/2019/09/20/chess-grandmaster-diet-exerc...