The “second wind” in McArdle's disease patients during a second bout of constant work rate submaximal exercise
- 1 May 2014
- journal article
- Published by American Physiological Society in Journal of Applied Physiology
- Vol. 116 (9), 1230-1237
- https://doi.org/10.1152/japplphysiol.01063.2013
Abstract
Patients with McArdle's disease (McA) typically show the “second-wind” phenomenon, a sudden decrease in heart rate (HR) and an improved exercise tolerance occurring after a few minutes of exercise. In the present study, we investigated whether in McA a first bout of exercise determines a second wind during a second bout, separated by the first by a few minutes of recovery. Eight McA (44 ± 4 yr) and a control group of six mitochondrial myopathy patients (51 ± 6 yr) performed two repetitions (CWR1 and CWR2) of 6-min constant work rate exercise (∼50% of peak work rate) separated by 6-min (SHORT) or 18-min (LONG) recovery. Pulmonary O2uptake (V̇o2), HR, cardiac output, rates of perceived exertion, vastus lateralis oxygenation {changes in deoxygenated Hb and myoglobin Mb concentrations, Δ[deoxy(Hb+Mb)], by near-infrared spectroscopy} were determined. In McA, V̇o2(0.86 ± 0.2 vs. 0.95 ± 0.1 l/min), HR (113 ± 10 vs. 150 ± 13 beats/min), cardiac output (11.6 ± 0.6 vs. 15.0 ± 0.8 l/min), and rates of perceived exertion (11 ± 2 vs. 14 ± 3) were lower, whereas Δ[deoxy(Hb+Mb)] was higher (14.7 ± 2.3 vs. −0.1 ± 4.6%) in CWR2-SHORT vs. CWR1; the “overshoot” of Δ[deoxy(Hb+Mb)] and the “slow component” of V̇o2kinetics disappeared in CWR2-SHORT. No differences (vs. CWR1) were observed in McA during CWR2-LONG, or in mitochondrial myopathy patients during both CWR2-SHORT and -LONG. A second-wind phenomenon was observed in McA during the second of two consecutive 6-min constant-work rate submaximal exercises. The second wind was associated with changes of physiological variables, suggesting an enhanced skeletal muscle oxidative metabolism. The second wind was not described after a longer (18-min) recovery period.Keywords
This publication has 48 references indexed in Scilit:
- Muscle oxygen transport and utilization in heart failure: implications for exercise (in)toleranceAmerican Journal of Physiology-Heart and Circulatory Physiology, 2012
- Gas exchange kinetics in obese adolescents. Inferences on exercise tolerance and prescriptionAmerican Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 2010
- Heterogeneous recruitment of quadriceps muscle portions and fibre types during moderate intensity knee‐extensor exercise: effect of thigh occlusionScandinavian Journal of Medicine & Science in Sports, 2009
- Influence of prior sprint exercise on the parameters of the ‘all‐out critical power test’ in menExperimental Physiology, 2009
- Dynamics of noninvasively estimated microvascular O2 extraction during ramp exerciseJournal of Applied Physiology, 2007
- Prior exercise speeds pulmonary O2 uptake kinetics by increases in both local muscle O2 availability and O2 utilizationJournal of Applied Physiology, 2007
- Prior heavy exercise elevates pyruvate dehydrogenase activity and speeds O2 uptake kinetics during subsequent moderate‐intensity exercise in healthy young adultsJournal Of Physiology-London, 2006
- A diagnostic cycle test for McArdle's diseaseAnnals of Neurology, 2003
- Effects of Prior Exercise on Metabolic and Gas Exchange Responses to ExerciseSports Medicine, 2003
- Metabolic MyopathiesMedicine, 1989