Not a single challenger has given the right answer to Theo's joke!

Theo, no matter how long you walk on your treadmill, no matter at what angle you fix it, the result is that you have walked 0 kilometres and 0 metres height gained.
Go out and have a real walk in a real environment!

Even in our own Netherlands there are enough little hills to get some physical exercise in walking uphill. For instance, go to Nijmegen and walk the old 20km N70 route. Though the hills are only 100m high, When you have done the route you will have gained more than 500m height.

Cheers, BART

Spot on, Bart. That's the trouble with abstract thinking!

Hi Bart,
my brother lives at the top of an appartmentbuilding and I used to go up and down the staircase will full backpack. Up was tough but going down always came to soon for proper stamina.
1,5k/20%/10kg will let me sweat a lot without driving for 80 min to Nijmegen.