Topic
Second wind
About: Second wind is a research topic. Over the lifetime, 12 publications have been published within this topic receiving 310 citations.
Papers
TL;DR: In this article, the authors evaluated the oxidative implications of the spontaneous second wind and variables that influence the development of this typical feature of McArdle disease, and showed that the increased muscle oxidative capacity is due to substrate-dependent increases in muscle oxygenated capacity.
Abstract: Background Blocked glycogen breakdown in McArdle disease impairs oxidative as well as anaerobic metabolism, but the contribution of impaired oxidative phosphorylation to everyday symptoms of McArdle disease remains poorly defined. Objective To evaluate the oxidative implications of the spontaneous second wind and variables that influence the development of this typical feature of McArdle disease. Design Assessment of exercise and oxidative capacity (VO 2 ) before and after the spontaneous "second wind" and with a glucose infusion after a spontaneous second wind. Patients Eight patients with complete myophosphorylase deficiency and 1 unique patient with 3% of normal myophosphorylase activity. Main Outcome Measures Work capacity, VO 2 , heart rate, cardiac output. Results All patients with complete myophosphorylase deficiency (1) had low peak VO 2 (mean ± SD, 13.0 ± 2.0 mL · kg −1 · min −1 ) in the first 6 to 8 minutes of exercise; (2) achieved a spontaneous second wind with increased exercise capacity between 8 and 12 minutes of exercise due to a more than 25% increase in peak VO 2 (16.5 ± 3.1 mL · kg −1 · min −1 ); and (3) with glucose infusion after a spontaneous second wind, experienced a further more than 20% increase in oxidative capacity (VO 2 , 19.9 ± 3.9 mL · kg −1 · min −1 ). In the patient with residual myophosphorylase, VO 2 (22.2 mL · kg −1 · min −1 ) in the first 6 to 8 minutes of exercise was approximately 2-fold higher than the mean of patients lacking myophosphorylase, and no significant improvement in exercise and oxidative capacity accompanied prolonged exercise or glucose infusion. Conclusions First, the spontaneous second wind and the glucose-induced second second wind in McArdle disease are due to substrate-dependent increases in muscle oxidative capacity. Second, by providing glycogen-derived pyruvate, a small amount of residual myophosphorylase activity normalizes the oxidative deficit of complete myophosphorylase deficiency and virtually eliminates the spontaneous second wind and glucose-induced second second wind.
153 citations
TL;DR: Patients with muscle phosphofructokinase deficiency are unable to achieve a spontaneous second wind under conditions that consistently produce one in patients with McArdle’s disease, and the ability to metabolize blood glucose is critical to the development of a typical spontaneoussecond wind.
Abstract: Objective: The spontaneous second wind in myophosphorylase deficiency (MD, McArdle’s disease) represents a transition from low to a higher exercise capacity attributable to increased oxidation of blood-borne fuels, principally glucose and free fatty acids. Muscle phosphofructokinase deficiency (PFKD) blocks the metabolism of muscle glycogen and blood glucose. The authors inquired whether the additional restriction in glucose metabolism in PFKD prevents a spontaneous second wind. Methods: The authors compared the ability of 29 patients with MD and 5 patients with muscle PFKD to achieve a spontaneous second wind during continuous cycle exercise after an overnight fast. Patients cycled at a constant workload for 15 to 20 minutes (3 MD patients, 3 PFKD patients) and at variable workloads in which peak exercise capacity was determined at 6 to 8 minutes of exercise and again at 25 to 30 minutes of exercise (29 MD patients, 4 PFKD patients). Heart rate was monitored continuously, and perceived exertion (Borg scale) was recorded during each minute of exercise. Oxygen utilization and blood levels of lactate and ammonia were determined at rest and during peak workloads. Results: All variables in both patient groups were similar at 6 to 8 minutes of exercise. Thereafter exercise responses diverged. Each MD patient developed a second wind with a decrease in heart rate and perceived exertion and an increase in work and oxidative capacity. In contrast, no PFKD patient developed a spontaneous second wind. Conclusions: Patients with muscle phosphofructokinase deficiency are unable to achieve a spontaneous second wind under conditions that consistently produce one in patients with McArdle’s disease. The authors conclude that the ability to metabolize blood glucose is critical to the development of a typical spontaneous second wind.
73 citations
TL;DR: During the 'second wind' phase there are no important differences between the metabolism of exercising muscle of patients with McArdle's disease and that of control subjects, and metabolic stress occurs during the adaptation phase.
Abstract: Three patients with McArdle's disease exercised for 2 h at 30% VO2max. During exercise two phases occurred. During the first 15 min they experienced progressive fatigue and weakness of exercised muscles, with a rapid and complete recovery (adaptation phase). Following this, all 3 patients were able to continue exercise without difficulty ('second wind' phase). During the adaptation phase, patients have to cope with their inability to use muscle glycogen as a fuel. Processes occurring during this phase are as follows. An increase in cardiac output. This might be expected to increase muscle blood flow in order to supply exercising muscle with substrates that can substitute for muscle glycogen (free fatty acids (FFA), bloodborne glucose). Changes in the metabolic pathways. These cause a sufficient amount of hexose phosphates to be present to overcome the first 2.5 min of exercise, and FFA and bloodborne glucose to play a major role in energy supply at an earlier stage in exercise than in control subjects. An increase in EMG activity. This is most probably caused by the recruitment of more motor units to compensate for a failure of force generation in the muscle fibres. Central command seems to play an important role in the regulation of cardiovascular processes during the adaptation phase. Despite these compensatory mechanisms, metabolic stress occurs during the adaptation phase. During the 'second wind' phase there are no important differences between the metabolism of exercising muscle of patients with McArdle's disease and that of control subjects.
73 citations
TL;DR: A second-wind phenomenon was observed in McArdle's disease during the second of two consecutive 6-min constant-work rate submaximal exercises, suggesting an enhanced skeletal muscle oxidative metabolism.
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....
26 citations
TL;DR: Carbon dioxide appeared to be the chief factor in the adjustment of the respiratory and circulatory systems to the demands of the muscles for an adequate supply of blood.
Abstract: Introduction .—It has long been known that the dyspnœa produced by strenuous exercise, such as running or rowing, disappears if the work is continued and is replaced by a sense of great relief, the so-called “second wind.” A certain time is necessary for the adjustment or accommodation which produces this sensation; short-distance runners do not experience it, but those who are accustomed to long runs over the same course can predict at which lap or point they will obtain the relief of second wind. There are also individual differences; in some men the sensation is very definite, in others so indefinite that it is unrecognised. The observations of Cook and Pembrey showed that during dyspnœa the percentage of carbon dioxide in the alveolar air was raised above the resting value and the respiratory quotient was unity or above unity, but daring the hyperpnœa following the onset of second wind the percentage of carbon dioxide and the respiratory quotient fell; the amount of air breathed per minute was less during hyperpnœa than during dyspnœa; the rectal temperature showed a rise of about 1° F. during second wind, and as a rule there was a close association between the onset of sweating and second wind. Carbon dioxide appeared to be the chief factor in the adjustment of the respiratory and circulatory systems to the demands of the muscles for an adequate supply of blood.
24 citations
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2018 | 1 |
| 2017 | 1 |
| 2015 | 1 |
| 2014 | 1 |
| 2011 | 1 |