Truly, exercise for Entrepreneurs can't be recommended enough. Before starting my Startup journey in 2006 I was 82-83 kgs (at around 6 feet, its sort of Okay). Went to 88 kgs, and felt bad in 2009. At present I am 80 kgs and feel much better.

My routine:

Runing: 7 kms on Tuesday and Thursday. 10 kms on Saturday.

Strength: Just body weight - push ups and pull ups and crunches - on Monday and Friday

Sprint runs: on Wednesday followed by some strength.

Overall time spend is about 1.5 hours each day (because I don't hurry, and a relaxed stretching session after running)

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