No! I want to know whether "cosmetic reasons" used in my context has any negative implications? By the way, in my context by saying "cosmetic reasons" I want to say doing exercise for having a better appearance, shape and...
I would use what you have suggested above: People need to exercise not only for their appearance but for their health. The problem with "cosmetic reasons" is that "cosmetic" is too often associated with the face.
Edit: To finally answer your question, "cosmetic reasons" is only negative in the sense that there are more important reasons to exercise, but we do things for cosmetic reasons all the time (which, speaking as a subway commuter, is appreciated in my fellow travelers).
Incidentally, I tend to understand and accept your "cosmetic reasons" not least of all because the word "cosmetic" is used in a similar way in my language. Not that it matters, but in my language we talk about "cosmetic repairs", "cosmetic defects", etc. Then, just to make sure, I looked it up in our dictionary, which said, among other things:cosmetic:...2. affecting only the appearance of something: the reform package was merely a cosmetic exercise.On the other hand, our American friends have a good point that "cosmetics", for instance, is associated with substances people apply on their faces (as opposed to their bodies).In a nutshell, I find it hard to decide whether "cosmetic reasons" is very appropriate. All I can say is that I personally understand it and accept it. And I don't see it as negative.
I wouldn't say that "cosmetic reasons" have a negative association, but it has a bit of a shallow feeling, that how the surface looks is more important than what's inside, in this case a person's health.
To expand on my post 4, "cosmetic reasons" by itself is neutral. How it is perceived will depend on the circumstance and the people involved.
In the context of "People need to exercise not only for cosmetic reasons but also for their health" it is somewhat negative because it is being compared to a better reason for exercising.
In the context of "After his car accident, he had plastic surgery for cosmetic reasons" is neutral or positive, in the sense that his plastic surgery was to repair damage rather than put a dimple in his chin.
And in the context of "She had a rhinoplasty for cosmetic reasons" could be negative, positive or neutral depending on the speaker, the audience, and their attitudes about having plastic surgery for other than medical reasons.