Like a dark shadow, the thought of the possibility of seasickness clouds many people’s enjoyment of cruises or a ship voyage, and the fear of fear of flying or airsickness makes some people forego air travel, preferring to go by train or car, although similar disturbances of well-being are possible here as well, only that they are commonly feared less than precisely seasickness and fear of flying (or airsickness). More and more often nowadays come to their doctor with the question about the nature and prevention of such disorders of well-being.
Common causes of motion sickness
The fear of the fear of flying or airsickness makes some people renounce air travel, preferring to travel by train or car, although similar disorders of well-being are also possible here. All disorders of well-being occurring during travel – whether seasickness, air sickness, rail sickness or car sickness – are due to a particular form of movement impulses imposed on the organism by the vehicle. The means of transport, in its turn, absorbs these movements from the road, rail, water or atmosphere. From this it can be seen that the fight against so-called travel sicknesses also has a technical side, and it is not impossible that the technical perfection of the means of transport could also have a beneficial effect here. Since these travel sicknesses are due to motion stimuli, they have been given the name “kinetoses” – derived from the Greek word “kinein” = to move.
Organic causes
These motion stimuli emanating from the vehicle are manifold in their physical nature and lead to a more or less strong irritation of the organ of equilibrium, also called the vestibular apparatus. This is located in the area of the inner ear and consists of the saccule and the semicircular canals. The first contains the well-known stones (otoliths), which stimulate certain sensory organs by means of pressure or traction and thus indicate changes in position. They thus mediate the perception of the position of the head in space and rectilinear movements, for example upward and downward movements. The function of the arcuates causes the perception of rotational movements. They are right-angled, semicircular channels filled with a fluid, the endolymph. During rapid movements, this fluid, due to its inertia, initially lags behind the wall; thus, there is displacement of the fluid and consequent differential excitation of the nerve endings present there. This excitation of the nervous parts of the organ of equilibrium is then finally transmitted to the brain via the eighth cranial nerve (nervus statoacusticus). The spatial changes that occur in short succession in stormy seas, swaying airplanes, and vibrating trains, which we cannot compensate for, force the nerve endings of the organ of equilibrium to pick up and send to the brain stimuli that far exceed normal levels. This in turn causes an inhibition of the highest sections of the brain, which in this way, so to speak, protect themselves against overload. The excitation impulses supplied to the organ of equilibrium but not absorbed are diverted to regions of the diencephalon. Here, an excitation focus is now created that becomes the vomiting center when it triggers emesis and vomiting, that is, when it discharges its electrical charge to the nerves and organs connected during vomiting.
Symptoms and signs
The first sign of the onset of motion sickness is often the onset of cold sweats or sweats. Soon after, other symptoms begin to appear: fatigue, loss of appetite, dizziness, gastrointestinal discomfort, diarrhea, increased salivation, headache and nausea. Finally, nausea and vomiting occur. The “feeling of annihilation” that often sets in more or less clearly in fully developed seasickness, which is an expression of the overload inhibition of numerous brain nerve cells, is likely to remain in the unpleasant memory of many a sea traveler for a long time to come. Disturbances of the heart and circulatory system are also known. They can be detected with suitable measuring devices, such as blood pressure or ECG apparatus. Breathing behaves differently; occasionally a deepening and acceleration of breathing can be seen (hyperventilation). Likewise, certain changes in the blood have also been described.All these changes characterize the influence of large areas of the central nervous system by the nerve impulses radiating from the organ of equilibrium. The order in which these symptoms occur, as well as their relative frequency and severity, varies from person to person. The most important objective sign of an onset of seasickness, other than pallor of the skin, remains vomiting. In the fully developed state, locomotor insufficiency occurs, making it practically impossible for the affected person to walk around upright.
Course and causes
All disorders of well-being that occur during travel – whether seasickness, airsickness, railroad sickness, or carsickness – are due to a particular form of locomotor impulses imposed on the organism by the vehicle. For example, how quickly air sickness or seasickness can develop depends on various circumstances. The type and duration of aircraft or ship motion play a major role. In the case of the airplane, the critical limit, according to some studies, is said to be a flight duration of about 2 ½ hours, while seasickness can be induced earlier under certain conditions. Of course, purely physical and psychological factors are equally important. The fear of getting seasick alone can promote its occurrence. The sight of seasick fellow travelers or the smell of vomit can trigger seasickness in people who have been spared it up to that point. In no case, however, should motion sickness be regarded as an expression of an abnormal mental disorder.
Seasickness
Seasickness is the best known and also the most common presentation of motion sickness. It has been known for as long as people have ventured out to sea in a ship. Already from the classical antiquity there are quite exact descriptions. Its frequency is sometimes stated quite differently. Some physicians estimate that 95 percent of all people can become seasick, while others speak of only about 40 percent. On large cruises, the frequency is in the range of a few percent, while on smaller, less conveniently designed ships it rises to almost 100 percent. Every seafarer knows that it is possible to get used to the ship’s movements to a large extent without getting seasick. However, this habituation is lost after a longer stay on land. Also, experience has taught that mental occupation and attempts at distraction are unlikely to prevent the onset of seasickness.
Air sickness or flight sickness
Air sickness (not fear of flying) shows a similar range of variation in frequency as seasickness, with influences of atmospheric turbulence, aircraft type, and above all flight duration playing an unmistakable role. Air sickness (not fear of flying) shows a similarly wide range in frequency as sea sickness, with influences of atmospheric turbulence, aircraft type and above all flight duration playing an unmistakable role. Modern aircraft with pressurized cabins generally fly at higher altitudes, where atmospheric turbulence decreases noticeably, so that the likelihood of contracting the disease is lower here than when flying at lower altitudes. The training effect is also evident in airsickness. Studies conducted at a flying school showed that more than 10 percent of all student pilots became airsick during their first flight, but only about 1 to 2 percent after the tenth flight. A longer flight duration favors the onset of airsickness. Here, however, mental occupation and distraction are able to delay or even prevent the onset of airsickness, which is why almost all airlines now offer their passengers movies and music for entertainment and distraction.
Motion sickness during bus travel, train travel and in the car
Other forms of motion sickness, such as those noticed in cars, buses, trains, and even amusement devices such as swings, air bikes, etc., have been described many times. In the case of trains and buses, some researchers estimate that the incidence of illness is about 4 percent. In automobiles, travel sickness symptoms are not infrequently confused with so-called car sickness, which is caused by inhalation of engine combustibles and is undoubtedly more dangerous. The question of how best to protect oneself from motion sickness is a difficult one to answer.A drug that helps safely in all cases has not yet been found, despite lengthy experiments. In quite a few cases, a favorable effect of meclozine and vitamin B6 preparations has been described, so that an attempt with such drugs is quite justified. Nevertheless, some of these agents can also cause unpleasant side effects, so in case of travel, the family doctor should be consulted first in this regard.
Prevent and treat seasickness and motion sickness.
The consumption of coffee, alcohol or cigarettes before and during a trip is evaluated differently. One is unlikely to have a fundamental success with it. We know from research that seasickness either does not occur at all or can be quickly alleviated in the supine position. Military studies have confirmed that seasickness rarely occurs in the supine position. However, if one now hung their head in the supine position, nearly 70 percent of Marines became seasick. With sitting persons it came in 60 per cent to the sea sickness. But as soon as they bent their heads backwards, seasickness did not occur. From this it can be concluded that head posture, but not body posture, is important for the development of motion sickness. As a result of these conditions, seasickness could possibly be reduced or partially prevented by lying on the back. Thus, it is the head posture and not the body posture that is important. The same is true for air sickness, so it is recommended that seats be changed to reclining for long duration flights.
Self-treatment and techniques
Beyond all these measures, it is largely in the hands of the individual – especially during flights – whether he or she survives them well. Following a law of nerve activity that any excitation of one area of the brain is inhibited by the stronger excitation of a neighboring section of the brain, one must strive to build up such a strong field of excitation oneself – that is, actively. Breathing is suitable for this, especially since it uses almost the same organs and nerves as vomiting. By breathing consciously and quickly – if possible involving the diaphragm and abdominal muscles – the excitation of the vomiting center cannot come about, and airsickness is prevented. In the case of seasickness, this method fails because the journey is usually so long that conscious breathing cannot be maintained. But the importance of this prevention of motion sickness, which is related to nervous activity, is shown by the fact that when driving a car the driver himself practically never falls ill, the passenger next to him seldom, but most frequently the rear passengers.
