Exercise is the miracle cure for everything, it would seem.
Though it'd be a moderate help if we could agree on what "counts as exercise" - a 15 minute walk? Resistance training (how many sets/reps)? HIIT? The fads can be tough on the average person who just wants health.
The book (Spark, link above) analyzes a handful of studies comparing the correlation between the type and duration of exercise, and its effects.
In short: you won't see any long lasting benefits from a single 15min. The best results were achieved at 75-85% of your aerobic capacity, at least a couple of hours per week (total).
You can also benefit from mixing simple aerobic exercises with others that require more coordination and fine movement of your body - martial arts, for example.
Swimming is a pretty good exercise for those who are bored by most other exercises. It may take six months or longer to see results from exercise, though, so it's hard to suggest exercise as a be-all-end-all fix.
Though it'd be a moderate help if we could agree on what "counts as exercise" - a 15 minute walk? Resistance training (how many sets/reps)? HIIT? The fads can be tough on the average person who just wants health.