Motion sickness, or kinetosis, affects some individuals when they are subjected to motion or movement. This can occur when they are travelling by air, road or on water.

The most common cause of motion sickness is a mismatch between the visual cues of motion and sensations of motion and position of the body by the vestibular apparatus deep within the ear.

As the brain struggles to make sense of the conflicting signals from these organs the symptoms of motion sickness are seen.

Symptoms of motion sickness include discomfort in the upper abdomen, nausea and so forth. 1-4

Upper abdomen discomfort

The symptom starts with a discomfort in the upper abdomen. This is usually a queasy feeling that may be unpleasant or may feel like fluttering within the abdomen. This is called stomach awareness.

This may not be unpleasant and if the provocative motion continues the other unpleasant symptoms begin.

Feelings of nausea

The mismatch between visual signals and those from the inner ear lead to stimulation of the vomiting center of the brain. This leads to feeling nauseous. This is usually preceded by a feeling of warmth and a desire to seek cool air

Other early symptoms

Other early symptoms include:-

• There may be early belching and flatulence as markers of onset of motion sickness.

• Dizziness

• Feelings of being unwell

• Getting pale. Pallor is seen common in the face and is accompanied with nausea.

Cold sweats

As the condition progresses the symptoms worse. This leads to a cold sweat. Patient is usually covered with a thin layer of sweat all over his or her body. Sweating bouts precede each bout of vomiting and severe nausea.

Other more progressive symptoms of motion sickness

Other symptoms that occur as the condition progresses include:-

• Feelings of weakness, fatigue and tiredness

• There may be mood swings, irritability lack of initiative and apathy

• Increased production of saliva and drooling

Vomiting in severe cases of motion sickness

Vomiting may occur in severe cases. Vomiting may relieve the symptoms temporarily. However, the motion sickness symptoms are not alleviated even after vomiting and retching may continue if the stomach is empty of contents.

The cycles of nausea up to vomiting with waxing and waning symptoms may continue till the travel is completed.

More severe symptoms

More severe symptoms include:-

• In more severe cases there may be a rapid, shallow breathing. Affliction of the respiratory system includes sighing and yawning that precede vomiting. Those who are anxious may also hyperventilate.

• There may be headaches. Those with migraine headaches may experience an attack of migraine while they experience motion sickness

• Drowsiness and sleepiness is common

• There may be increased excretion of anterior and posterior pituitary hormones during motion sickness. This may lead to elevation of the antidiuretic hormone (ADH) leading to reduced urination.

Mal de debarquement syndrome symptoms

Mal de debarquement syndrome (illness of disembarkation) is a more severe and rare form of motion sickness. The condition is triggered by travel usually by sea or by air.

The symptoms last long after the journey has finished. Those with this symptom after they have finished travel feel as though they are rocking or bobbing or moving even when they are not.

Many people normally feel this after a particularly long sea or air journey. However, those with this syndrome may experience these symptoms for months or even years after completion of their travel.