Doctors from Hunan Province in China reported a case of “mah-jongg-related deep-vein thrombosis.”Of course, anyone who's been to a chess tournament knows that good players spend a lot of time away from the board. Everything in moderation: Sitzfleisch is good, but so is walking! Kotov's Think Like a Grandmaster offers suggestions for organizing your thinking time away from the board: walking is a good time for long-range planning.
Hat tip to Andi Rosen. I'm off to get more coffee.