Recently, I read [an interesting story][1] about A. Weil and J.P. Serre. The general gist of the story is as follows: 


> During the Autumn of 1955, an international symposium on algebraic
> number theory was held at Nikko [a small city around 150 km north of
> Tokyo]. The Japanese mathematicians invited Weil and Serre on a trip
> to Lake Chuzenji. Upon arriving, Weil and Serre stripped down, and
> started swimming in the cold lake. The Japanese mathematicians
> followed suit, but they quickly gave up because of the cold. After a
> while, the two mathematicians came back out and started running. The
> Japanese mathematicians ran after the duo, but once again, they gave
> up. Eventually, Weil came back, smiled at the Japanese mathematicians,
> and said, "Math is all about physical stamina."

 


(My translation.)


I think the last Weil quote sums up the main message of the story. 

**My Question.** Based on people's experience, is this a true statement? If possible, I would like to hear what physical activities people pursue, and in what ways that has helped in doing mathematics.

I hope this is not too off-topic. I've never heard something like this from mathematicians I know personally, so I was curious to hear what the community thinks. 

  [1]: https://nc.math.tsukuba.ac.jp/column/emeritus/Kimurata/