Weightlessness... There is no person in the world who does not know the meaning of this word. And yet, only the select few experienced it. If you ask one of them to describe the sense of weightlessness, the ability to move in space almost without effort would be the most likely answer. However, this undoubtedly desirable effect of weightlessness is not the only one to consider.
The first flight into space lasted 108 minutes. Throughout this flight there were no significant adverse manifestations of weightlessness. During the second flight, "when Vostok-2, manned by German Titov, was launched into orbit, the cosmonaut experienced similar sensations as Yuri Gagarin. Titov's body initially was affected by the engine roar, vibration and overload, but then there was a sudden state of weightlessness. In the first moments of weightlessness Titov thought that he was in an inverted position. Some time later the confusion disappeared". (A popular history of astronomy and of space research. Author K. A. Lyakhova)
Only few astronauts are able to avoid nausea, which is one of the major effects caused by weightlessness on the human vestibular system. To compensate for the undesirable effects of weightlessness on the human body, astronauts undergo special training. If you wish, you can become familiar with the special techniques and equipment such as the swivel chair, orthopedic table, optokinetic drum.