Relation of Exercise Induced Bronchospasms by Anaerobic Exercise and Duration of Exercise

This study compared the influence of aerobice xercise with that of continuous anaerobic exercise on exercise-induced bronchospasms (EIB) in asthmatic children. Seven children with bronchial asthma underwent an incremental anaerobic exercise test to determine their maximal anaerobic power (Pmax.) with a high power cycle ergometer. Then, their maximal duration (100%T) was derermined at 80% of each Pmax. EIB by continuous anaerobic exercise were evaluated at duration levels (25%, 50%, 75%and100% of maximam) at 80% of Pmax. They also performed an aerobic EIB test for 6 min by the standard method. The following results were obtained. 1. The average maximal duration was 38.3±6.8 second. 2. Lactate increased remarkably in all tests except 25% of maximal duration. 3. There was no significant difference in VE between aerobic exercise and anaerobic exercise except at 25% of maximal duration. 4. The average max.%fall in FEV1.0 was 21.8±13.1% on aerobic exercise test. The average max.%fall in FEV1.0 on anaerobic exercise test was 9.7±11.3% at 100% of maximal dulation, 4.0±6.7% at 75%, 4.0±5.4% at 50% and 5.0±7.2% at 25%. (%fall in FEV1.0 at all durations of anaerobic exercise were under 10%) Max.%fall in FEV1.0 on 100%T which caused positive EIB was not different from that on aerobic exercise Based on. these results, it was concluded that the longest continuous anaerobic exercise may cause positive EIB. Because there was less rise of lactate, 25% of maximal duration was recommended for interval anaerobic exercise training.