>...my daily commute is a 6 km (3.7 mile) round trip by foot...I'm a male in my late 30s and I generally walk at a relatively brisk 7-8 km/h (4.3-5 mph)...My wa

>...my daily commute is a 6 km (3.7 mile) round trip by foot...I'm a male in my late 30s and I generally walk at a relatively brisk 7-8 km/h (4.3-5 mph)...My walk to work takes about 20 minutes... Does not compute. A trip of 3.7 miles at a speed of 5 miles per hour would take ~45 minutes. If you can actually walk your 6 km commute in 20 minutes, you should quit your job and start competing in Olympic race walking, since you are apparently outpacing the reigning world champion [1]. [1]http://en.wikipedia.org/wiki/Racewalking#20_km http://en.wikipedia.org/wiki/Racewalking#20_km