It is proved that acclimatization takes place in a period of five to seven days. If you are traveling on the ticket in a hot country just seven days, your body during the desired rest on the contrary, gets a lot of stress. It turns out that the man still not having to get used to the climate and undergo acclimatization in a new place, forced to go back - and his body shakes reacclimatization already, and he gets a double negative load.
With this in mind, the best is the rest period of 21 or 24 days. In this case, it would be great if the return home you will have left a few days of adaptation.
If you have recently had the disease (from the common cold to gastritis) or an operation, do not expose your body stress of climate change. In changing climatic zone your condition may worsen.
In that case, if you are expecting a baby, and should not abruptly change the climate.
There are age limits for children under 3 years of age and adults over 45 years is not recommended because of the winter rapidly move in the summer. Especially need to heed this advice to women during menopause.
If you have a chronic illness, do not rush to rest in tropical countries. This applies especially to people suffering from cardiovascular, broncho-pulmonary and allergic diseases, as well as with the pathology of the musculoskeletal system and psycho-emotional disorders. Given that the age of these diseases is significantly "younger", then perhaps the advice to consult a doctor can relate to all the tourists from 20 years. In addition, your doctor may advise you to holiday house or boarding house, working in particular, it is useful to you, climates.
When planning a vacation, think about how and how many steps you change time zones. Doctors believe that the body begins to experience stress already crossing one time zone, and the intersection of two time zones, especially at a fast pace - it is a real danger to health. If you still need to move from one time zone to another, possibly do it by train rather than plane.