A common problem in triathlons is the dizziness you feel when you exit after a long swim and are running or walking into transition. This is caused by the rush of blood away from the head, when standing after being horizontal in the swim for a long period. Sometimes called benign positional vertigo (BPV). It is short term and will go away, but it never helps you with a fast transition time.
So here are some simple steps that you can try, which may help you reduce the occurrence
Take some time to try out the ideas above until you find the one’s that work for you