Abstract
Introduction:
Understanding the normal dynamic physiological responses to the incremental shuttle walk test might enhance the interpretation of walking performance in clinical settings.
Objective:
To assess dynamic physiological responses to the incremental shuttle walk test and its predictors in healthy adults.
Methods:
We assessed the simultaneous rates of changes of Δoxygen uptake/Δwalking velocity (ΔVO2 /ΔWV), Δheart rate/Δoxygen uptake (ΔHR/ΔVO2 ), Δventilation/Δcarbon dioxide production (ΔVE/ΔVCO2 ), and Δtidal volume/Δlinearized ventilation (ΔVT/ΔlnVE) during the incremental shuttle walk test in 100 men and women older than 40 years. Fat and lean body masses (bioimpedance) were also evaluated.
Results:
We found that the dynamic relationships were not sex-dependent. Participants aged ≥ 70 presented declines in ΔVO2 /ΔWV slope compared to those aged 40-49 (215 ± 69 vs. 288 ± 84 mL.min-1.km.h-1). Obese participants presented shallower slopes for ΔVO2 /ΔWV (2.94 ± 0.90 vs. 3.84 ± 1.21 mL.min-1.kg-1.km.h-1) and ΔVT/ΔlnVE (0.57 ± 0.20 vs. 0.67 ± 0.26). We found negative influence of fat body mass on ΔVT/ΔlnVE (R2 = 0.20) and positive influence of lean body mass on ΔVO2 /ΔWV (R2 = 0.31), ΔHR/ΔVO2 (R2 = 0.25), and ΔVT/ΔlnVE (R2 = 0.44).
Conclusion:
Dynamic relationships during walking were slightly influenced by age, but not sex-dependent. Body composition played an important role in these indices. Our results may provide better interpretation of walking performance in patients with chronic diseases.
Keywords:
Exercise; Walking; Physical Fitness
