ORIGINAL ARTICLE

Cardiocirculatory and metabolic responses at different walking intensities

M Schwarz¹, A Urhausen², L Schwarz¹, T Meyer¹ and W Kindermann¹

¹ Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany
² Centre de l’ Appareil Locomoteur, de Medicine du Sport et de Prévention, Luxembourg

Correspondence to:
Correspondence to:
Dr Schwarz
Institute of Sports and Preventive Medicine, University of Saarland, Saarbrücken, Germany; mschwarz{at}mx.uni-saarland.de

Objectives: Although walking is a common physical activity, scientifically based training guidelines using standardised tests have not been established. Therefore this explorative study investigated the cardiovascular and metabolic load resulting from different walking intensities derived from maximal velocity (V_max) during an incremental treadmill walking test.

Methods: Oxygen uptake, heart rate (HR), blood concentrations of lactate and catecholamines, and rating of perceived exertion were recorded in 16 recreational athletes (mean (SD) age 53 (9) years) during three 30 minute walking trials at 70%, 80%, and 90% of V_max (V₇₀, V₈₀, and V₉₀) attained during an incremental treadmill walking test.

Results: Mean (SD) oxygen uptake was 18.2 (2.3), 22.3 (3.1), and 29.3 (5.0) ml/min/kg at V₇₀, V₈₀, and V₉₀ respectively (p<0.001). V₇₀ led to a mean HR of 110 (9) beats/min (66% HR_max), V₈₀ to 124 (9) beats/min (75% HR_max), and V₉₀ to 152 (13) beats/min (93% HR_max) (p<0.001). Mean (SD) lactate concentrations were 1.1 (0.2), 1.8 (0.6), and 3.9 (2.0) mmol/l at V₇₀, V₈₀, and V₉₀ respectively (p<0.001). There were no significant differences between catecholamine concentrations at the different intensities. Rating of perceived exertion was 10 (2) at V₇₀, 12 (2) at V₈₀, and 15 (2) at V₉₀. Twelve subjects reported muscular complaints during exercise at V₉₀ but not at V₇₀ and V₈₀.

Conclusions: Intensity and heart rate prescriptions for walking training can be derived from an incremental treadmill walking test. The cardiovascular and metabolic reactions observed suggest that V₈₀ is the most efficient workload for training in recreational athletes. Further studies are needed to confirm these findings.

Abbreviations: HR, heart rate; IAT, individual anaerobic threshold; ITWT, incremental treadmill walking test; RPE, rating of perceived exertion; V^·O₂, oxygen uptake

Keywords: walking test; velocity; oxygen uptake; heart rate; lactate

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