Abstract
In the present study, we assessed the time course of adaptations in peak oxygen uptake (V̇O2peak) and muscle fractional oxygen (O2) extraction (using near-infrared spectroscopy) following 12 wk of low-volume high-intensity interval training (HIIT) versus moderate-intensity continuous endurance training (MICT) in adults with uncomplicated type 2 diabetes (T2D). Participants with T2D were randomly assigned to MICT (n = 12, 50 min of moderate-intensity cycling) or HIIT (n = 9, 10 × 1 min at ∼90% maximal heart rate) or to a nonexercising control group (n = 9). Exercising groups trained three times per week and measurements were taken every 3 wk. The rate of muscle deoxygenation (i.e., deoxygenated hemoglobin and myoglobin concentration, Δ[HHb + Mb]) profiles of the vastus lateralis muscle were normalized to 100% of the response, plotted against % power output (PO), and fitted with a double linear regression model. V̇O2peak increased (P < 0.05) by week 3 of MICT (+17%) and HIIT (+8%), with no further significant changes thereafter. Total increases in V̇O2peak posttraining (P < 0.05) were 27% and 14%, respectively. The %Δ[HHb + Mb] versus %PO slope of the first linear segment (slope1) was reduced (P < 0.05) beyond 3 wk of HIIT and MICT, with no further significant changes thereafter. No changes in V̇O2peak or slope1 were observed in the control group. Low-volume HIIT and MICT induced improvements in V̇O2peak following a similar time course, and these improvements were likely, at least in part, due to an improved microvascular VO2 delivery.
Original language | English |
---|---|
Pages (from-to) | R683-R696 |
Number of pages | 14 |
Journal | American Journal of Physiology - Regulatory, Integrative and Comparative Physiology (AJP - Regulatory, Integrative and Comparative Physiology) |
Volume | 320 |
Issue number | 5 |
Early online date | 24 Feb 2021 |
DOIs | |
Publication status | Published - 1 May 2021 |
Keywords
- cardiorespiratory fitness
- exercise tolerance
- high-intensity interval training
- muscle deoxygenation
- near infrared spectroscopy