How do you claim athletes dont get acne?
There are many people who have been exercising for their whole lifes and still have acne. I think you are only talking about atheletes in the olympics and such. I think the top athletes don't get acne because they got pretty much the best genes you can get so their hormones are good anyway. There is also millions of dollars involved in sponsors so the athletes do everything to get more famous which is why they use make up and stuff to get a good skin and look good on magazines and such.
Athletes do get acne.
But you are right. Exercise, vitamin D as well as being outdoors in the light do improve acne. The right kind of exercise improves just about all the factors that lead to acne such as hormone balance, glucose metabolism, stress, inflammation, etc. However, athletes tend to do the wrong kind of exercise that promotes inflammation and can stimulate the hormones we acne prone people don't want stimulated. Although they do still get many of the other benefits.
The kind of exercise that is most beneficial without wasted effort and harmful effects is to do what humans are naturally meant to do and have systems designed to fuel and recover from. Move around a lot every day walking and doing chores. And do occasional spurts of intense activity such as lifting heaving things, sprinting, climbing, etc.