To some extent, fitness and sports can be regarded as synonyms, because they both refer to improving physical health and physical quality through physical exercise. However, from another perspective, they also have some differences.

Generally speaking, "sports" are more extensive, including various sports activities, such as running, swimming, basketball, football and so on. And "fitness" focuses more on shaping the body and improving the physical quality through exercise. So "fitness" is usually related to strength training, aerobic exercise, stretching and so on.

In addition, "fitness" has some specific meanings, such as equipment training in the gym or taking group courses. And "sports" are more extensive, including outdoor activities, leisure and entertainment.

In a word, the difference between "fitness" and "exercise" is not obvious, and they can be used interchangeably in some cases. However, in the specific context, we need to choose according to the actual situation.