Characteristics of the V̇O2 Slow Component During Heavy Exercise in Humans Aged 30 to 80 Years
At the onset of moderate intensity exercise oxygen uptake (V̇O2) increases exponentially from baseline to a new steady-state value. The steady-state V̇O2is linearly related to work rate, such that: ΔV̇O2/ΔWR ≈ 10 (ml·min-1·W-1. When the exercise intensity is heavy, inducing a sustained increase in blood lactate concentration, then the attainment of steady-state may be delayed, or even prevented, and a slow component of increasing V̇O2is observed (10). Thus, during heavy exercise the AV?̇O2/ΔWR relationship is increased (ΔV̇O2/ΔWR > 10) and becomes non-linear.
KeywordsWork Rate Slow Component Blood Lactate Concentration Ventilatory Threshold Muscle Fibre Type
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