It really depends on the mountain, which you should always research beforehand. For example, I climbed Mt. Massive in Colorado (second highest peak and >14k fe

It really depends on the mountain, which you should always research beforehand. For example, I climbed Mt. Massive in Colorado (second highest peak and >14k feet) without any special training or problems (I normally live near Washington DC). If you are in reasonably good shape (i.e. you run regularly) then you should be fine. Yeah, I stopped to catch my breath a little more frequently the higher I got, but it was a totally manageable 8 mile round trip.