[HEART RHYTHM VARIABILITY ANALYSIS AND ASSESSMENT OF THE SPINAL PAIN SYNDROME DURING DRY IMMERSION].

The spinal pain syndrome appears in cosmonauts on both short and long-duration missions. This untoward factor may affect body systems functioning and complicate the successful accomplishment of space mission. Purpose of the investigation was to examine the lumbar spine and to elucidate whether its condition relates to the spinal pain development and changes in heart rate variability (HRV) in the microgravity environment. The experiment was conducted in dry immersion as a method of microgravity effects simulation. It was shown that in dry immersion locomotion reproduces the patterns peculiar for significant gravitational unloading. Spinal pain intensity, angles and heights of the lumbar intervertebral discs and HRV were measured in 19 selected volunteers. During the experiment, all the volunteers developed pains in the back that abated gradually. Pain dependence on the height of intervertebral discs and cardiac regulatory mechanisms were investigated.