Exercise is great, I personally do yoga due to the relaxing nature which can help with my VS (visual snow) because stress can agitate it. As for more intense exercises, I haven't noticed any negative effect, however if you have VS and notice negative effects then it may be a good idea to lower the intensity. Exercise is a great way to improve your mental health, since physical and mental health are heavily linked. However exercise is no cure for any mental illness, and should not be treated as such, more of a healthy way of improving the symptoms.