What exactly causes motion sickness? A doctor weighs in.

Whether you’re sitting in a car or passing time on a boat, experiencing motion sickness while traveling can be deeply uncomfortable. 
Motion sickness is a common sensation that can lead to nausea and dizziness, and some people are more likely to experience it than others. Around one in three people are highly susceptible to feeling the sensation, according to studies. Experiencing motion sickness is not typically a cause for concern. 
To understand the complexities of motion sickness, USA TODAY spoke with a doctor to break down what exactly causes this unpleasant sensation. 
Motion sickness is a sensory disruption of the body’s balance center, says Dr. Susan Besser, MD, a board certified primary care provider who specializes in family medicine. Motion sickness is often experienced during travel, such as spending time on a rocking boat, a moving car or a plane, she says. 
Common symptoms linked to motion sickness include nausea, fatigue, headache, irritability, dizziness, sweating and salivation, according to Cleveland Clinic. A more serious symptom of motion sickness is vomiting, Besser says.
Generally speaking, there usually aren’t “serious consequences” to experiencing motion sickness, because once the stimulus is gone, your body’s balance center returns to normal, Besser says.  
Your body’s balance center is governed by three peripheral sensory systems: the visual field, the vestibular system, and the proprioceptive (sensory nerves) system, according to The University of Kansas Health system. 
The vestibular system, in particular, is a series of semicircular canals located in your inner ear, Besser says. These canals are filled with fluid, and they have the ability to sense the direction of your head movement.
To stabilize balance, the visual field, vestibular system and sensory nerve system send signals and sensory inputs to the brain. If these signals are not sent in sync, the brain must interpret confusing messages, Besser explains. 
For instance, if you’re sitting in a car looking down at your phone, your vision remains still, but the vestibular system senses motion, per WebMD. This type of action can result in feeling motion sickness. 
There are risk factors that make some people more likely to experience motion sickness.
Pre-existing medical conditions, such as benign paroxysmal positional vertigo (BPPV) and Parkinson’s disease, can make you more susceptible to motion sickness, according to Cleveland Clinic.
Children between the ages of 2-12 are more prone to experiencing motion sickness than adults, per Cleveland Clinic. Adults over the age of 50 are less susceptible to motion sickness, according to the CDC.  
More:What helps with nausea? Medical experts offer tips for feeling better
Menstrual periods, pregnancy, hormone replacement therapy and taking oral contraceptives are additional risk factors for motion sickness, per the CDC.