Abstract
Background: Recent studies have shown that physical training improves exercise capacity and health related quality of life (HRQoL) in asthmatics; however the best way to prescribe aerobic exercise intensity in these patients remains poorly known. Objective: To evaluate if predictive heart rate equations can be used to prescribe exercise intensity in subjects with moderate or severe asthma. Methods: Ninety-eight adults with moderate to severe asthma aged 36 (ranging from 24–53) years were submitted to a symptom-limited cardiopulmonary exercise testing (CPET) and anaerobic threshold (AT) was determined by two independent experienced reserchers. The association and agreement between maximum heart rate (HRmax) achieved on CPET and age-predicted Tanaka's maximum HR [208 – (0.7×age)] were evaluated, respectively, by Pearson's correlation and intraclass correlation coefficient. Similar analysis was applied between HR determined by CPET and heart rate reserve [(FCrest + 0.5 (HRmax-HRrest)], widely used to estimate exercise intensity at AT. Results: Maximal HR obtained by CPET was significantly lower than age-predictive equation (177.0 vs. 182.8 bpm, respectively, p<0.05). There was a weak correlation (p<0,001; r=0,46) and a weak agreement (p<0,001; ICC=0,26) between the achieved and estimated HRmax. At anaerobic threshold the HR obtained by CPET was similar to HR predicted equation (128 vs. 131 bpm, respectively, p>0.05), however, no correlation or agreement was observed between the HR (p>0.05). Conclusion: Exercise prescription for adults with moderate or severe asthma should be determined directly by an exercise test instead of using age-predicted equations.
- © 2012 ERS