I have heard that the slopes in Lisbon are significant. You must be adding to your quality and quantity of life by walking all the time.

It is great for walking if your joints are up to it. I get the impression of an erosive process (maybe glaciers?) that carved out valleys going out to the Tagus river. I live down near the river bank and my daily 5-7 km walks have about a 40-50 metre elevation change unless I just walk along the bank. Not a great city for biking, though, between the slopes and the very rough cobblestone pavement - I rented some of the Bolt bikes and the ride was so jolting that even though they were e-bikes, it was exceedingly unpleasant to go anywhere other than along certain parts of the river where there are bike paths. The bus service is pretty comprehensive but also pretty unpredictable, so sometimes when I go downtown to blues dance, I just walk the 6 km back home afterwards. I have not missed having a car at all.

Some folks up the hill a ways keep a flock of goats (that sometimes wander between nearby apartment buildings), so I get my exposure to nature, as well.