THE INFLUENCE OF EXERCISE AND DEHYDRATION ON POSTURAL STABILITY

The aim of this study was to investigate the effects of exercise-induc ed and thermal dehydration on postural balance. Eight male subjects cy cled for 2 h at a power output equal to 57-63% VO2max on two different occasions: once without drinking (NF) and once with intake of 1.91 of a carbohydrate-electrolyte solution (FR). Before and after the exerci se test, the velocity of the centre of pressure (COP) excursion was me asured on a force platform during 30-s bipedal standing in normal posi tion, feet side by side, and tandem position, feet heel to toe. On ano ther occasion, eight subjects underwent seven consecutive sauna sessio ns (85 degrees C, 50% rh) of 15 min duration with no fluid replacement (S) to induce thermal dehydration. Mean fluid loss was 2.7 (+/-0.4)%, 0.5 (+/-0.5)% and 3.0 (+/-0.6)% of body mass after NF, FR and S, resp ectively. Mean velocity of COP excursion after the exercise test was s ignificantly higher in the NF than in the FR trial (p<0.05). Postural stability was not influenced by S. In conclusion, prolonged exercise w ithout fluid ingestion seems to negatively affect postural stability, whereas no effect is observed after exercise with fluid replacement or after thermal dehydration.