Autonomic nervous system dysfunction is simply a dysfunction in one or all of these systems. Some symptoms that may indicate the presence of an autonomic nerve disorder include:
- dizziness and fainting upon standing up (orthostatic hypotension)
- inability to alter heart rate with exercise (exercise intolerance)
- sweating abnormalities, which could alternately be too much sweat or insufficient sweat
- digestion difficulties due to slow digestion. Resulting symptoms could include loss of appetite, bloating, diarrhea or constipation, and difficulty swallowing.
- urinary problems. These can include difficulty starting urination, incontinence, and incomplete emptying of the bladder
- sexual problems. In men, this could be difficulty with ejaculation and/or maintaining an erection. In women, this could be vaginal dryness and/or difficulty with orgasm
- vision problems. This could be blurry vision, or the failure of the pupils to react quickly enough to changes in light.
- tremor and muscle weakness, may also result from certain forms of autonomic dysfunction.
Autonomic testing is designed to determine how well your body is regulating your blood pressure and heart rate, and sometimes other functions. During these tests, your heart rate is measured using an electrocardiogram and your blood pressure using a cuff around your arm or finger. The tests include asking you to breathe deeply for two minutes, breathing as fast and as hard as you can for 30 seconds, maintaining a handgrip for 3 minutes, breathing against pressure for 15 seconds and placing your hand in ice water for 1 minute. All these tests are meant to stimulate your autonomic nervous system to produce changes in blood pressure and heart rate of short duration that reflect how well your involuntary nervous system is working.