I’d have to say that the most popular type of active holiday is the walking or hiking tour. The leisurely ones requiring little special equipment and are easy to “train” for. Or for the serious hiker the world is your oyster. So there’s pretty much something for everyone.
I’m frequently asked the difference between a walking and a hiking tour. The simple answer is that walking is for the most part along flat terrain, while hiking is up and down. But a walking tour isn’t necessarily easier than a hiking one: walking on cobblestones is in my experience harder than hiking on moss-covered trails. (Mind you I also hate walking in shopping malls.)
The tour operators are very helpful here because they will be very precise in spelling out what each trip entails. Every itinerary is graded, for example A as very leisurely and D as strenuous. (Walking tours usually have 4 categories, hiking tours may have more.) The tour company will explain on their site or in their brochure now much you’ll be doing each day, and even the altitude change you’ll experience. It all takes away a lot of the stress in the trip planning process.
The nice thing is that you don’t have to participate every day. If you are spending a couple of nights in the same hotel and one of you is fitter and wants to be as active as possible, while the other wants only a moderately active tour, then he or she can stay behind, vegging out or poking around the town. A nice compromise.
For an easy walking tour, I’d recommend France’s Loire Valley, Italy’s Chianti region (they have some wine there too, I hear), and South Africa, where you can do a “walking safari”. Moderate walking would be Spain’s Camino de Santiago; moderate hiking would be the Inca Trail in Peru. Want a hiking challenge? Mont Blanc in France or Mount Fuji in Japan. Not tough enough? Mount Kilimanjaro or Nepal Base Camp is for you.