Comparison of exercise capacity in adult asthmatic incremental shuttle walk test and incrementalcardiopulmonary exercise test

Background: the maximum tests are considered standard for assessment of exercise capacity, however; clinical trials as the Incremental Shuttle Walk Test (ISWT) are valid, reproducible and safe. Although, ISWT has been used to assess exercise capacity of patients with Chronic Obstructive Pulmonary Disease (COPD), there are few studies on metabolic and cardiovascular responses during ISWT in adult asthmatics. Aims: To compare the oxygen consumption (VO2 ml/min) and heart rate (HR%) obtained at peak ISWT and at incremental cardiopulmonary exercise test (ICPET) of asthmatics. Methods : 16 adult asthmatics (28 ± 8 years; FEV1 96±20% predictiveand FEV1/FVC 77±17% were evaluated. In two non-consecutive days, it was accomplished: ISWT and ICEPT on a treadmill (modified Balke) with VO2 uptake (Oxycon) and HR during the tests. Results: The distance traveled in ISWT was 538±86 meters, reaching 71±8% pred. The peak speed achieved in ICPET was 6 ± 0.6 km/h, the slope of 12 ± 2% and of 10 ± 1 minutes test. The values found in peak ISWT and ICPET, respectively were: VO2= 1955±499 vs. 1990±578 ml/min and VO2 provided corresponding to 103±17 vs. 104±21% of VO2 expected, no significant difference was found, however; in the case of percentage of predicted maximum heart rate (HRmax) = 85±10 vs. 91±9%, was found in ISWT lower value when compared to ICPET (p=0.008). Conclusion: We conclude the metabolic response in asthmatic patients was similar between the ISWT and ICPET, with lower cardiovascular demand at peak ISWT compared to ICPET. Financial support: no2011/23771-7 Sao Paulo Research Foundation (FAPESP) .