A Wii Fit report:
It's good! I'm not saying it's fun, because it only kind of is. It does a good job of giving you incentive to work out, and once I got enough stuff unlocked, it actually gave me a pretty good workout. It's funny, but once you accumulate 30 minutes of exercise on it, it makes a tinkly noise and the pig dances (there's a pig that counts up your minutes, why not?) for about 2 seconds. That tiny little nothing is enough to make it so that I always do my full 30 minutes no matter what. I can imagine there's something even more spectacular (assuming such a thing is possible) at 60 minutes, but I have no intention of ever finding out.
Other than having a lot of assorted back problems, I've always felt like I am in functional shape. Not good shape - very flabby, need work. But I feel like I can bend to pick things up, don't have to grunt getting out of a chair, run around as needed, and all that. Perfectly healthy and fine. Doing Wii Fit Yoga proved I was completely wrong. The exercises in the yoga section are all (at least up until the end few) extremely easy to actually do. They basically say "stand in this slightly awkward position for 20 seconds". But doing that, I'd feel like shards of glass were jabbing into my shoulders, and my arms would go numb. That is happening less and less, and things are getting better. I'm gaining little bits of flexibility I never knew I was missing. Sitting at a computer for 20 years will do that. So I am really glad to be working those kinks out again after so long.
I've tried various exercise tidbits throughout my decades of otherwise slothlike computer usage, and never has it been like this. I've even done serious stuff like six months of kickboxing, and a year or so of a full-fledged gym membership (where I actually went!). And those things would lower my weight (a teeny bit) and build some little muscles and all that, but running around and doing muscle-building is not the same as doing serious intensive stretching. As someone who has pretty severe back problems, I issue this as a challenge to you: get moving around! Not just aerobics, not just weight lifting, but get to stretching out your muscles. My hamstrings have for years been wound up tighter than a rubber-band airplane set for a transatlantic flight (I worked a long time coming up with that metaphor, so don't mock it), and I just ignore it because it doesn't limit me... but it's bad for the back! I thought I was getting in shape when I was doing the gym, and I was losing fat and gaining muscle, but there's a whole other side to things you just don't think about usually. And if you do too good of a job building up muscle, you're just making the flexibility problem even worse.
And Wii Fit will show it to you! Enjoy the pain.