Totally agree (swimming and running in my case), but this leads us to the next very controversial question -- how much our free time off the job during the day,

Totally agree (swimming and running in my case), but this leads us to the next very controversial question -- how much our free time off the job during the day, impacts our results on the job (so shouldn't we have more of it)? I know I am not creative past 6-7 hours a day at work. This question is of course applicable only to people in positions where creativity is heavily involved in producing the value.