Although travel can be fun, according to the Madrid College of Psychologists, it can also expose the traveller to obvious and hidden dangers, which can lead to illness or aggravate existing health problems. Lack of sleep, combined with stress, dehydration, increased levels of exertion, musculoskeletal strains and changing health care delivery systems can affect the traveller.However, some disorders are caused by the process of moving from one part of the world to another. Thus, the four most common conditions caused by travel are:
- Jet Lag: Long-distance travel where several time zones are crossed in a short period of time can cause what is known as jet lag, also called rapid time zone shift syndrome or desynchronisation. This disorder is caused by the circadian rhythm - the internal clock, which is attuned to the day-night cycle at the place of departure - being out of sync with the day-night cycle at the destination, with little or no time to adjust.jet lag affects air travellers in particular because of the greater distances and time zones covered in a relatively short time. Boaters may have some difficulty with this condition if they do not regularly settle in while travelling the world.
- Motion sickness: Motion sickness - commonly known as motion sickness - is any disorder caused by motion, such as seasickness, airsickness or car sickness, as defined by Taber's Cyclopean Medical Dictionary. It is a common ailment of travellers on ships or planes, in motor vehicles and even when riding animals such as horses.Most people, including experienced sailors and frequent air travellers, have experienced motion sickness at one time or another. All that is needed is a sufficiently strong stimulus, which can vary greatly from person to person. Most people acclimatise - or "get their sea legs back" - over time, but the process can take up to two or three days.
- Deep vein thrombosis: Deep vein thrombosis (DVT) is an acute condition in which a blood clot (also known as a thrombus) forms in one or more deep veins in the body, usually in the legs. These blood clots can break loose, travel through the bloodstream and cause life-threatening conditions such as a pulmonary embolism, a blood clot that lodges in the lungs. The blockage can be large enough to reduce the heart's ability to circulate blood to the lungs, impairing vital functions such as carbon dioxide removal and oxygen supply.
- Altitude sickness: Travelling to high altitudes exposes people to increasingly rarefied air and a decreasing amount of oxygen, resulting in a decrease in blood oxygen levels, which can lead to impaired physical and mental performance. The response to altitude varies, but most people can function normally at altitudes up to 2,438 metres above sea level. At higher altitudes, oxygen deficiency can begin to cause a condition known as acute mountain sickness (AMS). At altitudes above 3,048 metres, 75% of people experience at least mild symptoms of AMS.