scholarly journals Moderate exercise may prevent the development of severe forms of COVID-19, whereas high-intensity exercise may result in the opposite

2021 ◽  
pp. 110705
Author(s):  
BA. Hagiu
Keyword(s):  
High Intensity ◽  
High Intensity Exercise ◽  
Moderate Exercise

scholarly journals Effect of Acute and Chronic Oral l-Carnitine Supplementation on Exercise Performance Based on the Exercise Intensity: A Systematic Review

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4359
Author(s):  
Juan Mielgo-Ayuso ◽  
Laura Pietrantonio ◽  
Aitor Viribay ◽  
Julio Calleja-González ◽  
Jerónimo González-Bernal ◽  
...  
Keyword(s):  
Systematic Review ◽  
Exercise Performance ◽  
High Intensity ◽  
Perceived Exertion ◽  
Cycle Ergometer ◽  
High Intensity Exercise ◽  
Rating Of Perceived Exertion ◽  
Acute Administration ◽  
Moderate Exercise ◽  
Performance Variables

l-Carnitine (l-C) and any of its forms (glycine-propionyl l-Carnitine (GPL-C) or l-Carnitine l-tartrate (l-CLT)) has been frequently recommended as a supplement to improve sports performance due to, among others, its role in fat metabolism and in maintaining the mitochondrial acetyl-CoA/CoA ratio. The main aim of the present systematic review was to determine the effects of oral l-C supplementation on moderate- (50–79% V˙O2 max) and high-intensity (≥80% V˙O2 max) exercise performance and to show the effective doses and ideal timing of its intake. A structured search was performed according to the PRISMA® statement and the PICOS guidelines in the Web of Science (WOS) and Scopus databases, including selected data obtained up to 24 October 2021. The search included studies where l-C or glycine-propionyl l-Carnitine (GPL-C) supplementation was compared with a placebo in an identical situation and tested its effects on high and/or low–moderate performance. The trials that used the supplementation of l-C together with additional supplements were eliminated. There were no applied filters on physical fitness level, race, or age of the participants. The methodological quality of studies was evaluated by the McMaster Critical Review Form. Of the 220 articles obtained, 11 were finally included in this systematic review. Six studies used l-C, while three studies used l-CLT, and two others combined the molecule propionyl l-Carnitine (PL-C) with GPL-C. Five studies analyzed chronic supplementation (4–24 weeks) and six studies used an acute administration (<7 days). The administration doses in this chronic supplementation varied from 1 to 3 g/day; in acute supplementation, oral l-C supplementation doses ranged from 3 to 4 g. On the one hand, the effects of oral l-C supplementation on high-intensity exercise performance variables were analyzed in nine studies. Four of them measured the effects of chronic supplementation (lower rating of perceived exertion (RPE) after 30 min at 80% V˙O2 max on cycle ergometer and higher work capacity in “all-out” tests, peak power in a Wingate test, and the number of repetitions and volume lifted in leg press exercises), and five studies analyzed the effects of acute supplementation (lower RPE after graded exercise test on the treadmill until exhaustion and higher peak and average power in the Wingate cycle ergometer test). On the other hand, the effects of l-C supplementation on moderate exercise performance variables were observed in six studies. Out of those, three measured the effect of an acute supplementation, and three described the effect of a chronic supplementation, but no significant improvements on performance were found. In summary, l-C supplementation with 3 to 4 g ingested between 60 and 90 min before testing or 2 to 2.72 g/day for 9 to 24 weeks improved high-intensity exercise performance. However, chronic or acute l-C or GPL-C supplementation did not present improvements on moderate exercise performance.

Peripheral and Central Chemoreceptor Control of Ventilation During Exercise in Humans

1994 ◽  
Vol 19 (3) ◽  
pp. 305-333 ◽  
Author(s):  
Susan A. Ward
Keyword(s):  
Steady State ◽  
High Intensity ◽  
High Intensity Exercise ◽  
Moderate Exercise ◽  
Arterial Blood Gas ◽  
Respiratory Compensation ◽  
Arterial Blood ◽  
The Stability ◽  
Exercise In Humans ◽  
Humoral Control

The stability of arterial blood gas tensions and pH during steady-state moderate exercise has suggested an important humoral element of ventilatory control in humans. However, the involvement of central and peripheral chemoreflexes in this humoral control remains controversial. This reflects, in large part, technical and interpretational limitations inherent in currently used estimators of chemoreflexes "sensitivity." Evidence suggests that the central chemoreceptors (a) contribute little during moderate exercise, given the relative stability of cerebrospinal pH, (b) constrain the hyperpnea of high-intensity exercise, consequent to the respiratory compensation for the metabolic acidemia, and (c) may play a role in the respiratory compensation during chronic metabolic acidemia. In contrast, the peripheral chemoreceptors appear to (a) exert considerable influence on ventilatory kinetics in moderate exercise, but are less important in the steady state, and (b) induce much of the respiratory compensation of high-intensity exercise. Key words: medullary chemoreceptors, carotid chemoreceptors, hyperoxia, ventilatory dynamics, metabolic acidemia

Dietary nitrate supplementation reduces the O2cost of low-intensity exercise and enhances tolerance to high-intensity exercise in humans

2009 ◽  
Vol 107 (4) ◽  
pp. 1144-1155 ◽  
Author(s):  
Stephen J. Bailey ◽  
Paul Winyard ◽  
Anni Vanhatalo ◽  
Jamie R. Blackwell ◽  
Fred J. DiMenna ◽  
...  
Keyword(s):  
High Intensity ◽  
Submaximal Exercise ◽  
High Intensity Exercise ◽  
Moderate Intensity ◽  
Nitrate Content ◽  
Time To Exhaustion ◽  
Moderate Exercise ◽  
Dietary Nitrate ◽  
Nitrate Supplementation ◽  
Exercise In Humans

Pharmacological sodium nitrate supplementation has been reported to reduce the O2cost of submaximal exercise in humans. In this study, we hypothesized that dietary supplementation with inorganic nitrate in the form of beetroot juice (BR) would reduce the O2cost of submaximal exercise and enhance the tolerance to high-intensity exercise. In a double-blind, placebo (PL)-controlled, crossover study, eight men (aged 19–38 yr) consumed 500 ml/day of either BR (containing 11.2 ± 0.6 mM of nitrate) or blackcurrant cordial (as a PL, with negligible nitrate content) for 6 consecutive days and completed a series of “step” moderate-intensity and severe-intensity exercise tests on the last 3 days. On days 4–6, plasma nitrite concentration was significantly greater following dietary nitrate supplementation compared with PL (BR: 273 ± 44 vs. PL: 140 ± 50 nM; P < 0.05), and systolic blood pressure was significantly reduced (BR: 124 ± 2 vs. PL: 132 ± 5 mmHg; P < 0.01). During moderate exercise, nitrate supplementation reduced muscle fractional O2extraction (as estimated using near-infrared spectroscopy). The gain of the increase in pulmonary O2uptake following the onset of moderate exercise was reduced by 19% in the BR condition (BR: 8.6 ± 0.7 vs. PL: 10.8 ± 1.6 ml·min−1·W−1; P < 0.05). During severe exercise, the O2uptake slow component was reduced (BR: 0.57 ± 0.20 vs. PL: 0.74 ± 0.24 l/min; P < 0.05), and the time-to-exhaustion was extended (BR: 675 ± 203 vs. PL: 583 ± 145 s; P < 0.05). The reduced O2cost of exercise following increased dietary nitrate intake has important implications for our understanding of the factors that regulate mitochondrial respiration and muscle contractile energetics in humans.

scholarly journals Intensity-Dependent Effects of Acute Exercise on Executive Function

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Aylin Mehren ◽  
Cecilia Diaz Luque ◽  
Mirko Brandes ◽  
Alexandra P. Lam ◽  
Christiane M. Thiel ◽  
...  
Keyword(s):  
Executive Function ◽  
Cardiorespiratory Fitness ◽  
High Intensity ◽  
Acute Exercise ◽  
Brain Activation ◽  
High Intensity Exercise ◽  
Moderate Intensity ◽  
Behavioral Performance ◽  
Moderate Exercise ◽  
Beneficial Effects

Numerous studies suggest beneficial effects of aerobic exercise at moderate intensity on cognition, while the effects of high-intensity exercise are less clear. This study investigated the acute effects of exercise at moderate and high intensities on executive functions in healthy adults, including functional MRI to examine the underlying neural mechanisms. Furthermore, the association between exercise effects and cardiorespiratory fitness was examined. 64 participants performed in two executive function tasks (flanker and Go/No-go tasks), while functional MR images were collected, following two conditions: in the exercise condition, they cycled on an ergometer at either moderate or high intensity (each n=32); in the control condition, they watched a movie. Differences in behavioral performance and brain activation between the two conditions were compared between groups. Further, correlations between cardiorespiratory fitness and exercise effects on neural and behavioral correlates of executive performance were calculated. Moderate exercise compared to high-intensity exercise was associated with a tendency towards improved behavioral performance (sensitivity index d′) in the Go/No-go task and increased brain activation during hit trials in areas related to executive function, attention, and motor processes (insula, superior frontal gyrus, precentral gyrus, and supplementary motor area). Exercise at high intensity was associated with decreased brain activation in those areas and no changes in behavioral performance. Exercise had no effect on brain activation in the flanker task, but an explorative analysis revealed that reaction times improved after high-intensity exercise. Higher cardiorespiratory fitness was correlated with increased brain activation after moderate exercise and decreased brain activation after high-intensity exercise. These data show that exercise at moderate vs. high intensity has different effects on executive task performance and related brain activation changes as measured by fMRI and that cardiorespiratory fitness might be a moderating factor of acute exercise effects. Thus, our results may contribute to further clarify the neurophysiological mechanisms underlying the beneficial effects of exercise on cognition.

Noninvasive ventilation can modulate heart rate variability during high-intensity exercise in COPD-CHF patients

Heart & Lung ◽  
2021 ◽  
Vol 50 (5) ◽  
pp. 609-614
Author(s):  
Giovana Salgado Baffa ◽  
Cássia da Luz Goulart ◽  
Flávia Rossi Caruso ◽  
Adriana S. Garcia de Araújo ◽  
Polliana Batista dos Santos ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Noninvasive Ventilation ◽  
High Intensity ◽  
High Intensity Exercise

scholarly journals Sudden Cardiac Death Risk in Downhill Skiers and Mountain Hikers and Specific Prevention Strategies

2021 ◽  
Vol 18 (4) ◽  
pp. 1621
Author(s):  
Josef Niebauer ◽  
Martin Burtscher
Keyword(s):  
Risk Factors ◽  
Risk Factor ◽  
Sudden Cardiac Death ◽  
High Intensity ◽  
Cardiac Death ◽  
High Intensity Exercise ◽  
Systemic Hypertension ◽  
Physical Strain ◽  
Mountainous Regions ◽  
Downhill Skiing

Sudden cardiac death (SCD) still represents an unanticipated and catastrophic event eliciting from cardiac causes. SCD is the leading cause of non-traumatic deaths during downhill skiing and mountain hiking, related to the fact that these sports are very popular among elderly people. Annually, more than 40 million downhill skiers and mountain hikers/climbers visit mountainous regions of the Alps, including an increasing number of individuals with pre-existing chronic diseases. Data sets from two previously published case-control studies have been used to draw comparisons between the SCD risk of skiers and hikers. Data of interest included demographic variables, cardiovascular risk factors, medical history, physical activity, and additional symptoms and circumstances of sudden death for cases. To establish a potential connection between the SCD risk and sport-specific physical strain, data on cardiorespiratory responses to downhill skiing and mountain hiking, assessed in middle-aged men and women, have been included. It was demonstrated that previous myocardial infarction (MI) (odds ratio; 95% CI: 92.8; 22.8–379.1; p < 0.001) and systemic hypertension (9.0; 4.0–20.6; p < 0.001) were predominant risk factors for SCD in skiers, but previous MI (10.9; 3.8–30.9; p < 0.001) and metabolic disorders like hypercholesterolemia (3.4; 2.2–5.2; p < 0.001) and diabetes (7.4; 1.6–34.3; p < 0.001) in hikers. More weekly high-intensity exercise was protective in skiers (0.17; 0.04–0.74; p = 0.02), while larger amounts of mountain sports activities per year were protective in hikers (0.23; 0.1–0.4; <0.001). In conclusion, previous MI history represents the most important risk factor for SCD in recreational skiers and hikers as well, and adaptation to high-intensity exercise is especially important to prevent SCD in skiers. Moreover, the presented differences in risk factor patterns for SCDs and discussed requirements for physical fitness in skiers and hikers will help physicians to provide specifically targeted advice.

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