Reading a book or checking a phone during a car journey can trigger nausea, dizziness and sweating in some passengers. Conflicting signals from the eyes and inner ear help explain why, according to Dr Chaithanya Ravikumar, a physician at Koshys Hospital.
Speaking to Hindustan Times, Dr Ravikumar said motion sickness develops when the brain receives mismatched information about movement. The eyes focus on a relatively stationary page or screen, while the inner ear detects the moving vehicle.
“The inner ear contains specialised structures that detect changes in movement, direction and acceleration. When a person is travelling in a car, these structures continuously communicate movement-related information to the brain,” explained Dr Ravikumar.
Reading creates the visual impression that the surroundings are stationary, despite the movement the balance system detects. This mismatch can activate pathways responsible for motion sickness, causing headache and sometimes vomiting alongside nausea and dizziness.
The US Centers for Disease Control and Prevention also describes motion sickness as a disagreement between visual information and inner-ear sensations. Similar symptoms can occur on trains, boats, aircraft and amusement park rides.
Susceptibility varies with age, genetic predisposition, migraine history and sensitivity to sensory conflicts, Dr Ravikumar said. Children aged two to twelve face a greater risk, although people of any age can experience symptoms.
People with migraines may also experience motion-related nausea and dizziness more readily.
Frequent acceleration, braking and turns can intensify symptoms by adding stimulation to the balance system. Reading in the back seat may worsen discomfort because passengers have a limited view of the road ahead.
Poor ventilation, strong odours, anxiety, fatigue and dehydration can aggravate symptoms in susceptible travellers, the doctor added.
“The simplest preventive measure is to avoid reading or looking at a phone while the vehicle is moving. Instead, looking outside at the horizon or at distant, relatively stable objects can help the brain reconcile visual information with the movement detected by the inner ear,” advised Dr Ravikumar.
For adults, sitting in the front passenger seat may help. Children should remain in age-appropriate restraints and seating.
Keeping the head relatively still, improving ventilation and taking breaks during longer journeys may also reduce discomfort. Britain’s NHS recommends fresh air, slow breathing and avoiding heavy meals, spicy foods and alcohol before or during travel.
People with significant symptoms can consult a doctor about medication. Some treatments cause drowsiness and do not suit everyone. The CDC advises checking suitability and dosing with a healthcare professional, particularly for children.
Motion sickness during reading is generally harmless and does not necessarily signal an underlying medical condition. However, symptoms outside travel require attention.
“However, if dizziness or nausea occurs frequently even when the person is not travelling, persists after the journey, or is accompanied by severe headache, hearing changes, difficulty walking or other neurological symptoms, medical evaluation is advisable to rule out other causes,” highlighted Dr Ravikumar.
