Priming exercise accelerates oxygen uptake kinetics during high-intensity cycle exercise in middle-aged individuals...

Area of Science:

• Exercise Physiology
• Cardiovascular Health
• Metabolic Disorders

Background:

• Individuals with type 2 diabetes (T2D) exhibit slower pulmonary oxygen uptake kinetics ( $\stackrel{·}{V}{O}_2$ τ _p) during submaximal exercise, attributed partly to impaired oxygen supply to muscles.
• This limitation can hinder exercise performance and adaptation in this population.

Purpose of the Study:

• To investigate if high-intensity priming exercise (PE) can accelerate pulmonary oxygen uptake kinetics ( $\stackrel{·}{V}{O}_2$ τ _p) in middle-aged adults with T2D.
• To determine if PE enhances oxygen delivery and utilization during subsequent high-intensity cycling exercise in T2D.

Main Methods:

• Eleven middle-aged adults with T2D and eleven healthy controls underwent four cycling tests.
• Two tests included a high-intensity priming exercise (PE) before a constant-load exercise bout.
• Pulmonary oxygen uptake ( $\stackrel{·}{V}{O}_2$ ) and vastus lateralis muscle deoxygenation ([HHb + Mb]) were measured.

Main Results:

• Baseline $\stackrel{·}{V}{O}_2$ τ _p was significantly slower in the T2D group (48 ± 6s) compared to controls (34 ± 2s).
• Priming exercise (PE) significantly reduced $\stackrel{·}{V}{O}_2$ τ _p in the T2D group (32 ± 6s), making it comparable to controls.
• PE also reduced the $\stackrel{·}{V}{O}_2$ slow component amplitude in both groups, without altering muscle deoxygenation kinetics.

Conclusions:

• Priming exercise effectively accelerates pulmonary oxygen uptake kinetics in middle-aged adults with T2D.
• This improvement is likely mediated by enhanced oxygen delivery matching oxygen utilization.
• PE also attenuates the $\stackrel{·}{V}{O}_2$ slow component during subsequent high-intensity exercise.