TY - JOUR
T1 - Influence of type 2 diabetes on muscle deoxygenation during ramp incremental cycle exercise
AU - Gildea, Norita
AU - Rocha, Joel
AU - McDermott, Adam
AU - O'Shea, Donal
AU - Green, Simon
AU - Egaña, Mikel
PY - 2019
Y1 - 2019
N2 - We tested the hypothesis that type 2 diabetes (T2D) alters the profile of muscle fractional oxygen (O2) extraction (near-infrared spectroscopy) during incremental cycle exercise. Seventeen middle-aged individuals with uncomplicated T2D and 17 controls performed an upright ramp test to exhaustion. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. Peak oxygen uptake was significantly (P < 0.05) reduced in individuals with T2D. The %Δ[HHb+Mb]/%PO slope of the first linear segment of the double linear regression function was significantly (P < 0.05) steeper in T2D than controls (1.81±0.61 vs 1.35±0.43). Both groups displayed a near-plateau in Δ[HHb+Mb] at an exercise intensity (%PO) not different amongst them. Such findings suggest that a reduced O2 delivery to active muscles is an important underlying cause of exercise intolerance during a maximum graded test in middle-aged individuals with T2D.
AB - We tested the hypothesis that type 2 diabetes (T2D) alters the profile of muscle fractional oxygen (O2) extraction (near-infrared spectroscopy) during incremental cycle exercise. Seventeen middle-aged individuals with uncomplicated T2D and 17 controls performed an upright ramp test to exhaustion. The rate of muscle deoxygenation (i.e. deoxygenated haemoglobin and myoglobin concentration, Δ[HHb+Mb]) profiles of the vastus lateralis muscle were normalised to 100% of the response, plotted against % power output (PO) and fitted with a double linear regression model. Peak oxygen uptake was significantly (P < 0.05) reduced in individuals with T2D. The %Δ[HHb+Mb]/%PO slope of the first linear segment of the double linear regression function was significantly (P < 0.05) steeper in T2D than controls (1.81±0.61 vs 1.35±0.43). Both groups displayed a near-plateau in Δ[HHb+Mb] at an exercise intensity (%PO) not different amongst them. Such findings suggest that a reduced O2 delivery to active muscles is an important underlying cause of exercise intolerance during a maximum graded test in middle-aged individuals with T2D.
KW - cycling
KW - muscles
KW - near infrared spectroscopy
KW - non-insulin-dependent diabetes
UR - http://hdl.handle.net/1959.7/uws:52757
U2 - 10.1016/j.resp.2019.103258
DO - 10.1016/j.resp.2019.103258
M3 - Article
SN - 1569-9048
VL - 269
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
M1 - 103258
ER -
