I've heard about the endorphin thing; I think it's happened to me exactly once, after climbing a mountain, and it was really creepy and I don't want it to happen again. The only thing I feel when finishing exercise is 'oh thank god that's over'.
What I've found is that the more I train, the fitter I get, and so the longer I can prolong the discomfort, stress and boredom. Maybe you're not one of those people --- but if you are, I'm sorry.
(In fact, the most annoying thing are that the people who do enjoy exercise simply don't believe any of this, and produce unhelpful platitudes like 'you just haven't found something you like yet' or 'but if you keep doing it you'll find you're enjoying it'...)
Yes, I can walk reasonably long distances at the drop of a hat and without difficulty, and I can exercise in the gym, but every time I've done that, I never felt the high. I don't think I ever will.
I guess I'll just have to be glad when it's over.
I don't really follow my own advice, but I used to boulder regularly when I lived in Berlin, and I liked it.
Competitive sports --- flat no. They just don't keep my attention.
What I do is run, because I can build that into my commute, so it doesn't feel like it's a complete waste of time. Right now I'm capable of making myself run to work twice a week, 7km each time, which is okay. Hopefully when summer comes round again I'll start running back again as well.
One, do it gradually -- if you're feeling sick, maybe you should be ramping up more slowly. While muscle can grow quickly, tendons and ligaments take much longer to handle the new workload.
Two, form makes all the difference -- running can either feel heavy and difficult, or lightweight and joyous. But unfortunately, it can take a lot of learning and effort to get to the latter -- good relaxed form is not easy to learn, landing the right way on your foot is incredibly important, for some people things like Vibram shoes help, you might have severe muscle tension preventing good form (see a massage therapist, get a Theracane and use it religiously, etc.), you might have horribly tight hamstrings and need specific stretches for those, the list goes on and on. Me personally, I also had to lose a bunch of weight (getting down to my ideal BMI) for running to feel light and easy rather than painful and pounding.
And third, being in the right mood for enjoying running makes a huge difference too. When I'm not in the mood for it, but I run anyways (because I'm feeling guilty about not running, etc.), I generally stay miserable. But sometimes I really am in the mood for it -- I got enough sleep the night before, I ate a couple hours ago so I have energy, but not so long ago I'm hungry, it's not too early in the day (I'm not a morning person), but not too late either that I'm tired -- finding the right time is huge, and makes all the difference.
Honestly, I love running, but it took a lot of time and effort to figure out everything above that made it work for me -- in my case, years. (And pretty much everything about the programmer lifestyle works against you.) But when you manage to make everything align, it feels great, like you're tapping some kind of primal happiness where you're back on the African savannah tracking down antelope... I'm not even joking.
I guess every person has it's own rhythm.
This sounds counter-intuitive, but you should be going slow enough to hold a conversation.
If you're going much faster, especially when you're just starting out, it's no wonder you're not enjoying it.
Running really feels meditative at this pace. And it builds a strong aerobic base for more intensive work later on.
Here's a cheap book that lays out the research on why this is so often the advice that works: https://www.amazon.com/80-20-Running-Stronger-Training-ebook...
I have since picked up (slowly) running without shoes on and it has made a real difference. It is difficult to acclimate, but it can be done. I now feel no knee pain and I have realized that I indeed enjoy running. Not only am I discovering that it's easier to run without shoes, but it's a lot more fun too.
Indeed I haven't seen most of the changes in my feet that others say they have seen in theirs. My feet are mostly the same, but with soles that are just a little less sensitive to pebbles and sticks than they used to be.
Maybe I'm lucky, but even in a big city that practically glitters with broken beer bottles and I don't find glass to be a problem. Injuries from broken glass are easy to avoid, and are much more often talked about than realized. Once a season I may get a splinter in my foot, or stub my toe on a root, but that's about the worst of it.
There are no real experts on barefoot living yet and if there are I would not be one. But since you asked, in my experience it took a month or so of being consistently barefoot for my soles to begin to feel like they were changing. They're still changing, slowly, a year later.
You get used to the feeling of the concrete on your soles, just like you get used to anything. Then, like anything you get used to, you notice it less and less.
The only real drawback to being barefoot outside is that a lot of people will look at you like you're crazy. They'll tell you you're going to get injured. That there's glass on the ground. Many of these people will be in pumps or wedges. You just learn to let it humor you on the inside.
For one, getting zoning out within no time, and second, being fit enough to comfortably run 45-60min.
I've been training for about three months now and I spent about 6 weeks of that feeling sick the entire time, and the more recent 6 weeks just not enjoying it.