If dizziness and nausea occur after swimming, the following reasons need to be considered: First, swimming for a long time, the body is more tired, which may cause the brain function to decline, resulting in dizziness symptoms, this time should pay attention to rest, and generally will be significantly improved. Second, if dizziness occurs in the elderly and is serious, the possibility of cerebral insufficiency should be considered. You can go to the neurology department of a regular hospital to check and measure blood pressure, see if there is hypertension or hypotension, and do carotid ultrasound and transcranial Doppler. If you are unstable or have severe vertigo, you should also have a brain CT test, and according to the test results, you can take oral medications to improve brain circulation, such as Cipro. When swimming, you must do the preparation activities before swimming to avoid dizziness after a long time swimming.