THE EFFECT OF EXPOSURE TO NEGATIVE AIR IONS ON THE RECOVERY OF PHYSIOLOGICAL-RESPONSES AFTER MODERATE ENDURANCE EXERCISE

This study examined the effects of negative air ion exposure on the hu man cardiovascular and endocrine systems during rest and during the re covery period following moderate endurance exercise. Ten healthy adult men were studied in the presence (8,000-10,000 cm(-3)) or absence (20 0-400 cm(-3)) of negative air ions (25 degrees C, 50% humidity) after 1 h of exercise. The level of exercise was adjusted to represent a 50- 60% load compared with the subjects' maximal oxygen uptake, which was determined using a bicycle ergometer in an unmodified environment (22- 23 degrees C, 30-35% humidity, 200-400 negative air ions.cm(-3)). The diastolic blood pressure (DBP) values during the recovery period were significantly lower in the presence of negative ions than in their abs ence. The plasma levels of serotonin (5-HT) and dopamine (DA) were sig nificantly lower in the presence of negative ions than in their absenc e. These results demonstrated that exposure to negative air ions produ ced a slow recovery of DBP and decreases in the levels of 5-HT and DA in the recovery period after moderate endurance exercise. 5-HT is thou ght to have contributed to the slow recovery of DBP.