Bout Of Cycling Exercise Research Articles

Vascular limitations in blood pressure regulation with age in women: Insights from exercise and acute cardioselective β-blockade.

Younger women rely on altering cardiac output ( ) to regulate blood pressure (BP). In contrast, older women rely more on altering vascular tone. However, evidence suggests that the ability to alter systemic vascular conductance (SVC) is diminished in older women. In the present study, cardioselective β-blockade was utilized to diminish the relative contribution of to BP regulation and thereby evaluate age-related vascular limitations in women at rest and during large muscle dynamic exercise. Younger (n=13, mean age 26.0 years) and older (n=14, mean age 61.8 years) healthy women performed submaximal bouts of semi-recumbent cycling exercise at varying intensities while receiving an intravenous infusion of esmolol, a β1-antagonist, or saline control in a repeated-measures crossover design. was attenuated during esmolol infusion, with greater reductions during exercise (moderate, -1.0 (95% CI, -1.6 to -0.5)L/min, P<0.001; heavy, -2.0 (95% CI, -2.6 to -1.5)L/min, P<0.001) than seated rest (-0.5 (95% CI, -1.1 to 0.0)L/min, P=0.048), and this reduction was not significantly different between age groups (P=0.122). Older women exhibited a greater attenuation in mean arterial pressure (MAP) during esmolol (-7 (95% CI, -9 to -4) mmHg, P<0.001) relative to younger women (-2 (95% CI, -5 to 0) mmHg, P=0.071). These changes coincided with a greater reduction of SVC in the younger women during esmolol (-15 (95% CI, -20 to -10)mL/min/mmHg, P<0.001) compared to older women (-3 (95% CI, -9 to 2)mL/min/mmHg, P=0.242). Together, these findings provide evidence that older, postmenopausal women have a diminished ability to adjust SVC in order to regulate MAP.

The Impact of Exercise Intensity and Sex on Endogenous Ghrelin Levels and Appetite in Healthy Humans.

Ghrelin circulates in acylated (AG) and deacylated (DAG) forms, which are known to affect appetite. Although acute exercise has been shown to modulate ghrelin levels, data on the impact of exercise intensity on AG and DAG levels and their effects on appetite are sparse and primarily limited to males. To investigate the effect of exercise intensity and sex on ghrelin levels and appetite in untrained humans. Eight males (age: 43.1 ± 10.9 years; body mass index [BMI]: 22.2 ± 1.7 kg/m2; peak oxygen consumption [VO2peak]: 36.3 ± 6.4 mL/kg/min) and 6 females (age: 32.2 ± 11.1 years; BMI: 22.7 ± 1.0 kg/m2; VO2peak: 29.2 ± 4.0 mL/kg/min) completed a maximal graded cycle ergometer lactate threshold (LT)/VO2peak test. These data were used to determine the exercise intensity on 3 subsequent randomized control or calorically matched cycle exercise bouts: (1) CON, no exercise; (2) MOD, the power output at LT; (3) HIGH, the power output associated with 75% of the difference between LT and VO2peak. Perception of appetite was analyzed using visual analog scales. Females had higher levels of total ghrelin (TG) (P = .03) and DAG (P = .01) at baseline than males. Both groups exhibited reduced DAG levels in HIGH compared with MOD and CON (P < .0001-.004); however, only females had significantly reduced AG in HIGH (P < .0001). Hunger scores were higher in MOD than in CON (P < .01). High-intensity may be superior to moderate-intensity exercise for reducing ghrelin levels and modifying hunger, and sex may impact this response.

Effects of Sports Bras and Breast Volume on Pulmonary System and Respiratory Symptom Responses to Exercise in Healthy Females.

This study assessed the individual and combined effects of sports bras and breast volume on pulmonary system and respiratory symptom responses to exercise in recreationally-active females. Twenty-three healthy females (18-27 y; bra sizes 32B-36DDD) were divided into small and large breast volume groups (SBV and LBV, respectively) around median volume (324 ml; mean ± SD SBV: 284 ± 38 ml vs. LBV: 560 ± 97 ml; p < 0.001, g = 3.84). Participants completed three 5-minute bouts of constant-load cycle exercise at 30, 60, and 90% of their peak power output while wearing a high-support sports bra, low-support sports bralette, or their own (self-selected) sports bra in randomized order. Measurements included ventilation, breathing pattern, respiratory pressures, diaphragm electromyogram (EMGdi), and ratings of perceived exertion (RPE), breathlessness (intensity and unpleasantness) and chest tightness due to bra. Compared to low-support and personal sports bras, the high-support sports bra evoked stronger sensations of restricted breathing and chest tightness ('slight' to 'moderate' restriction in n = 7 [30%] vs. n = 1 [4%] in low-support and personal bras; p = 0.014). There was, however, no evidence of greater concomitant inspiratory constraints, EMGdi, or inspiratory muscle pressure generation in either bra (all p > 0.05). Notably, LBV compared to SBV participants reported greater RPE (p = 0.037, ηp2 = 0.20), breathlessness intensity (p = 0.039, ηp2 = 0.20) and unpleasantness (p = 0.041; ηp2 = 0.19), which, in the setting of comparable pulmonary system responses to exercise, was likely driven by stronger perceived chest tightness and/or bra awareness in LBV participants. Despite evoking mild-to-moderately severe chest tightness due to bra during exercise - correctly fitted sports bras, whether low- or high-support, do not impose a physiological burden to the respiratory system and its response to mild-to-heavy intensity exercise in otherwise healthy females.

Exercise transiently increases the density of incipient blood clots in antiplatelet-treated lacunar stroke patients

IntroductionOlder individuals and, in particular, individuals at risk of recurrent stroke, may be susceptible to thrombosis when participating in exercise, however, this aspect has not been well investigated.MethodsClot microstructure and conventional markers of thrombotic risk were determined in twenty lacunar stroke patients and fifteen healthy age-matched controls before, immediately after and 1 h after a bout of moderate intensity cycling exercise. Data were analyzed using a linear mixed model approach.ResultsAt rest, clot microstructure (1.69 ± 0.07 vs. 1.64 ± 0.05, corresponding to a difference of ~ 50% in normalized clot mass; p = 0.009) and thrombocyte count (73%; p < 0.0001) were higher, and activated partial thromboplastin time was lower (18%; p = 0.0001) in stroke patients compared to age-matched controls. Acute exercise increased thrombogenic markers similarly in the two groups: incipient clot microstructure (1.69 ± 0.07 vs. 1.74 ± 0.05; p = 0.0004 and 1.64 ± 0.05 vs. 1.71 ± 0.04; p < 0.0001, for stroke and controls respectively), plasma fibrinogen (12%; p < 0.0001 and 18%; p < 0.0001, for stroke and controls respectively) and the combined coagulation factors II, VII and X (p = 0.0001 and p < 0.0001, for stroke and controls respectively).ConclusionThe results show that exercise transiently increases the risk of blood clot formation in both stroke patients and controls, however, due to the higher baseline thrombogenicity in stroke patients, the post exercise risk of forming blood clots may be higher in this group.Trial registrationRegistered at ClinicalTrials.gov (NCT03635177).

Acute exercise-induced release of innate immune proteins via small extracellular vesicles changes with aerobic fitness and age.

Physical exercise triggers the secretion of small extracellular vesicles (sEVs) into the circulation in humans, enabling signalling crosstalk between tissues. Exercise-derived EVs and their cargo have been proposed to mediate adaptations to exercise; however, our understanding of how exercise-derived EV protein cargo is modulated by factors such as aerobic fitness and age of an individual is currently unknown. Here, we examined the circulating sEV proteome following aerobic exercise in healthy males of different ages and aerobic fitness to understand exercise-induced EV response during the aging process. Twenty-eight healthy men completed a bout of 20-min cycling exercise at 70% estimated VO2peak . Small EVs were isolated from blood samples collected before and immediately after exercise, and then quantified using particle analysis and Western blotting. Small EV proteome was examined using quantitative proteomic analysis. We identified a significant increase in 13 proteins in small plasma EVs following moderate-to-vigorous intensity exercise. We observed distinct changes in sEV proteome after exercise in young, mature, unfit, and fit individuals, highlighting the impact of aerobic fitness and age on sEV protein secretion. Functional enrichment and pathway analysis identified that the majority of the significantly altered sEV proteins are associated with the innate immune system, including proteins known to be damage-associated molecular patterns (DAMPs). Together, our findings suggest that exercise-evoked acute stress can positively challenge the innate immune system through the release of signalling molecules such as DAMPs in sEVs, proposing a novel EV-based mechanism for moderate-to-vigorous intensity exercise in immune surveillance pathways.

Pedaling to Performance: Exploring the Effects of Pre-Tournament Cycling on Rocket League Esports Performance

ABSTRACT Purpose Exercise has been well documented to elicit cognitive benefits; therefore, we aimed to examine the effect on performance of a single bout of cycling exercise before an esports tournament. Methods Twenty healthy males (age, 24 ± 6 yr; height, 177.3 ± 7.3 cm; body mass, 80.7 ± 20.9 kg; ranked between Gold 1 and Champion 3) participated in a randomized, counterbalanced crossover study involving 1) a 20-min cycling exercise bout at 60%–70% heart rate reserve or 2) 20 min of rest before competing in an esports tournament. Tournaments consisted of 10 paired, rank-matched Rocket League 1 vs. 1 matches played in three series. Participants were assessed before and after the tournament for hemodynamics, cognition, and gameplay mechanics. Heart rate was monitored throughout the tournament, with gameplay performance and post-match surveys completed after each match. Results Exercising before the tournament led to higher initial fatigue (P = 0.002), higher average heart rates throughout the tournament (P &lt; 0.001), lower perceived individual performance in series 1 (P = 0.03), lower overall perceived opponent performance (P = 0.03), and improved goal percentage in series 3 (P = 0.04) compared with rest. Participant save percentage decreased over time in both conditions (P = 0.04). No differences were observed in cognition measures, gameplay mechanics, or hemodynamics. Conclusions A single bout of cycling exercise completed before a Rocket League 1 vs. 1 tournament had no negative effects on performance or wins. It did, however, lower perceived match performance and fatigue at the beginning of the tournament while improving goal percentage during the last series.

Exploratory assessment of right ventricular structure and function during prolonged endurance cycling exercise

BackgroundA reduction in right ventricular (RV) function during recovery from prolonged endurance exercise has been documented alongside RV dilatation. A relative elevation in pulmonary artery pressure and therefore RV afterload during exercise has been implicated in this post-exercise dysfunction but has not yet been demonstrated. The current study aimed to assess RV structure and function and pulmonary artery pressure before, during and after a 6-h cycling exercise bout.MethodsEight ultra-endurance athletes were recruited for this study. Participants were assessed prior to exercise supine and seated, during exercise at 2, 4 and 6 h whilst cycling seated at 75% maximum heart rate, and post-exercise in the supine position. Standard 2D, Doppler and speckle tracking echocardiography were used to determine indices of RV size, systolic and diastolic function.ResultsHeart rate and RV functional parameters increased from baseline during exercise, however RV structural parameters and indices of RV systolic and diastolic function were unchanged between in-exercise assessment points. Neither pulmonary artery pressures (26 ± 9 mmHg vs 17 ± 10 mmHg, P > 0.05) nor RV wall stress (7.1 ± 3.0 vs 6.2 ± 2.4, P > 0.05) were significantly elevated during exercise. Despite this, post-exercise measurements revealed RV dilation (increased RVD1 and 3), and reduced RV global strain (− 21.2 ± 3.5 vs − 23.8 ± 2.3, P = 0.0168) and diastolic tissue velocity (13.8 ± 2.5 vs 17.1 ± 3.4, P = 0.019) vs pre-exercise values.ConclusionA 6 h cycling exercise bout at 75% maximum heart rate did not alter RV structure, systolic or diastolic function assessments during exercise. Pulmonary artery pressures are not elevated beyond normal limits and therefore RV afterload is unchanged throughout exercise. Despite this, there is some evidence of RV dilation and altered function in post-exercise measurements.

The human skeletal muscle metaboreflex contribution to cardiorespiratory control in males and females in dynamic exercise.

There is a significant effect of sex and muscle mass on the cardiorespiratory response to the skeletal muscle metaboreflex during isometric exercise. We therefore tested the hypothesis that sex differences would be present when isolated following dynamic exercise. We also tested the hypothesis that single and double leg post-exercise circulatory occlusion (PECO) following heavy exercise would elicit a cardiorespiratory response proportional to the absolute muscle mass. Healthy (24±4 years) males (n=10) and females (n=10) completed pulmonary function and an incremental cycle test to exhaustion. Participants completed two randomized, 6 min bouts of intense cycle exercise (84±7% V̇O2peak). One exercise bout was immediately followed by 3 min PECO (220mmHg) of the legs while the other exercise bout was followed by passive recovery. Males completed an additional session of testing with single leg PECO. The mean arterial pressure during PECO and control was greater in males compared to females (p=0.004). The was a significant time by condition by sex interaction in the heart rate response to PECO (p=0.027). There was also a significant condition by sex interaction in the ventilatory response to PECO (p=0.026). In males, we observed a dose-dependent cardiovascular, but not ventilatory, response to muscle mass occluded (all p<0.05). Our findings suggest the metaboreflex contribution to cardiorespiratory control during dynamic exercise is greater in males compared to females. The ventilatory response induced by double-leg occlusion but not single-leg occlusion, suggests that the ventilatory influence of the metaboreflex is less sensitive than the cardiovascular response and may be linked to the greater afferent activation induced by double-leg occlusion.

Ageing attenuates exercise-enhanced motor cortical plasticity.

Cardiorespiratory exercise is known to modulate motor cortical plasticity in young adults, but the influence of ageing on this relationship is unknown. Here, we compared the effects of a single session of cardiorespiratory exercise on motor cortical plasticity in young and older adults. We acquired measures of cortical excitatory and inhibitory activity of the primary motor cortex using transcranial magnetic stimulation (TMS) from 20 young (mean±SD = 25.30 ± 4.00 years, 14 females) and 20 older (mean±SD = 64.10 ± 6.50 years, 11 females) healthy adults. Single- and paired-pulse TMS measurements were collected before and after a 20min bout of high-intensity interval cycling exercise or an equivalent period of rest, and again after intermittent theta burst stimulation (iTBS). In both young (P = 0.027, Cohen's d = 0.87) and older adults (P = 0.006, Cohen's d = 0.85), there was an increase in glutamatergic excitation and a reduction in GABAergic inhibition from pre- to postexercise. However, in contrast to younger adults, older adults showed an attenuated plasticity response to iTBS following exercise (P = 0.011, Cohen's d = 0.85). These results demonstrate an age-dependent decline in cortical plasticity and indicate that a preceding bout of high-intensity interval exercise might be less effective for enhancing primary motor cortex plasticity in older adults. Our findings align with the hypothesis that the capacity for cortical plasticity is altered in older age. KEY POINTS: Exercise enhances motor cortical plasticity in young adults, but how ageing influences this effect is unknown. Here, we compared primary motor cortical plasticity responses in young and older adults before and after a bout of high-intensity interval exercise and again after a plasticity-inducing protocol, intermittent theta burst stimulation. In both young and older adults, exercise led to an increase in glutamatergic excitation and a reduction in GABAergic inhibition. Our key result was that older adults showed an attenuated plasticity response to theta burst stimulation following exercise, relative to younger adults. Our findings demonstrate an age-dependent decline in exercise-enhanced cortical plasticity and indicate that a preceding bout of high-intensity interval exercise might be less effective for enhancing primary motor cortex plasticity in older adults.

Consequences of sarcolemma fatigue on maximal muscle strength production in patients with myalgic encephalomyelitis/chronic fatigue syndrome

BackgroundMyalgic encephalomyelitis is an invalidating chronic disease often associated with exercise-induced alterations of muscle membrane excitability (M wave). No simultaneous measurements of maximal isometric force production and sarcolemma fatigue in the same muscle group have been previously reported. We hypothesized that M wave alterations could be partly responsible for the reduced muscle force present in this invalidating disease. MethodsThis retrospective study compared two groups of patients who presented (n = 30) or not (n = 28) alterations of M waves evoked by direct muscle stimulation during and after a cycling exercise bout. The maximal handgrip strength was measured before and after exercise, concomitantly with electromyogram recordings from flexor digitorum longus muscle. The patients also answered a questionnaire to identify eventual exacerbation of their clinical symptoms following the exercise test. FindingsThe M wave amplitude significantly decreased in muscles and the M wave duration significantly increased in the group of patients with M wave alterations after exercise. Resting values of handgrip were significantly lower in patients with exercise-induced M-wave alterations than in patients without M-wave abnormalities. In patients with exercise-induced M-wave alterations, handgrip significantly decreased after exercise and the changes in handgrip and M wave were positively correlated. The frequency of post-exertion malaise, increased fatigue, myalgia, headache and cognitive dysfunction was significantly higher in patients with M-wave alterations and variations in handgrip after exercise. InterpretationThese data suggest that post-exercise sarcolemma fatigue often measured in patients with myalgic encephalomyelitis could be the cause of muscle failure.

The impact of natural menstrual cycle and oral contraceptive pill phase on substrate oxidation during rest and acute submaximal aerobic exercise.

Previous research has identified sex differences in substrate oxidation during submaximal aerobic exercise including a lower respiratory exchange ratio (RER) in females compared with males. These differences may be related to differences in sex hormones. Our purpose was to examine the impact of the natural menstrual cycle (NAT) and second- and third-generation oral contraceptive pill (OCP2 and OCP3) cycle phases on substrate oxidation during rest and submaximal aerobic exercise. Fifty female participants (18 NAT, 17 OCP2, and 15 OCP3) performed two experimental trials that coincided with the low (i.e., nonactive pill/early follicular) and the high hormone (i.e., active pill/midluteal) phase of their cycle. RER and carbohydrate and lipid oxidation rates were determined from gas exchange measurements performed during 10 min of supine rest, 5 min of seated rest, and two 8-min bouts of submaximal cycling exercise at ∼40% and ∼65% of peak oxygen uptake (V̇o2peak). For all groups, there were no differences in RER between the low and high hormone phases during supine rest (0.73 ± 0.05 vs. 0.74 ± 0.05), seated rest (0.72 ± 0.04 vs. 0.72 ± 0.04), exercise at 40% (0.77 ± 0.04 vs. 0.78 ± 0.04), and 65% V̇o2peak (0.85 ± 0.04 vs. 0.86 ± 0.03; P > 0.19 for all). Similarly, carbohydrate and lipid oxidation rates remained largely unchanged across phases during both rest and exercise, apart from higher carbohydrate oxidation in NAT vs. OCP2 at 40% V̇o2peak (P = 0.019) and 65% V̇o2peak (P = 0.001). NAT and OCPs do not appear to largely influence substrate oxidation at rest and during acute submaximal aerobic exercise.NEW & NOTEWORTHY This study was the first to examine the influence of NAT and two generations of OCPs on substrate oxidation during rest and acute submaximal aerobic exercise. We reported no differences across cycle phases or groups on RER, and minimal impact on carbohydrate or lipid oxidation apart from an increase in carbohydrate oxidation in NAT compared with OCP2 during exercise. Based on these findings, NAT/OCP phase controls may not be necessary in studies investigating substrate oxidation.

Carbohydrate, but not fat, oxidation is reduced during moderate-intensity exercise performed in 33 vs. 18°C at matched heart rates.

Exposure to environmental heat stress increases carbohydrate oxidation and extracellular heat shock protein 70 (HSP70) concentrations during endurance exercise at matched absolute, external work rates. However, a reduction in absolute work rate typically occurs when unacclimated enduranceathletes train and/or compete in hot environments. We sought to determine the effect of environmental heat stress on carbohydrate oxidation rates and plasma HSP70 expression during exercise at matched heart rates (HR). Ten endurance-trained, male cyclists performed two experimental trials in an acute, randomised, counterbalanced cross-over design. Each trial involved a 90-min bout of cycling exercise at 95% of the HR associated with the first ventilatory threshold in either 18 (TEMP) or 33°C (HEAT), with ~ 60% relative humidity. Mean power output (17 ± 11%, P < 0.001) and whole-body energy expenditure (14 ± 8%, P < 0.001) were significantly lower in HEAT. Whole-body carbohydrate oxidation rates were significantly lower in HEAT (19 ± 11%, P = 0.002), while fat oxidation rates were not different between-trials. The heat stress-induced reduction in carbohydrate oxidation was associated with the observed reduction in power output (r = 0.64, 95% CI, 0.01, 0.91, P = 0.05) and augmented sweat rates (r = 0.85, 95% CI, 0.49, 0.96, P = 0.002). Plasma HSP70 and adrenaline concentrations were not increased with exercise in either environment. These data contribute to our understanding of how moderate environmental heat stress is likely to influence substrate oxidation and plasma HSP70 expression in an ecologically-valid model of endurance exercise.

D2 receptor blockade eliminates exercise-induced changes in cortical inhibition and excitation

BackgroundAlthough cardiorespiratory exercise is known to affect cortical excitatory and inhibitory activity, the neurochemical mechanisms driving this effect are poorly understood. Animal models of Parkinson's disease identify dopamine D2 receptor expression as a candidate mechanism, but the link between the D2 receptor and exercise-induced changes in cortical activity in humans is unknown. ObjectiveHere, we examined the effect of a selective dopamine D2 receptor antagonist, sulpiride, on exercise-induced changes in cortical activity. MethodsWe acquired measures of excitatory and inhibitory activity of the primary motor cortex using transcranial magnetic stimulation (TMS) from 23 healthy adults, both before and after a 20-min bout of high-intensity interval cycling exercise. We examined the effect of D2 receptor blockade (800 mg sulpiride) on these measures within a randomised, double-blind, placebo-controlled crossover design. ResultsSulpiride abolished exercise-induced modulation of the cortical excitation:inhibition balance relative to placebo (P < 0.001, Cohen's d = 1.76). Sulpiride blocked both the increase in glutamatergic excitation and reduction in gamma-aminobutyric acid (GABA) inhibition that was observed following exercise in the placebo condition. ConclusionOur results provide causal evidence that D2 receptor blockade eliminates exercise-induced changes in excitatory and inhibitory cortical networks, and have implications for how exercise should be prescribed in diseases of dopaminergic dysfunction.

Human lymphocytes mobilized with exercise have an anti-tumor transcriptomic profile and exert enhanced graft-versus-leukemia effects in xenogeneic mice.

Every bout of exercise mobilizes and redistributes large numbers of effector lymphocytes with a cytotoxic and tissue migration phenotype. The frequent redistribution of these cells is purported to increase immune surveillance and play a mechanistic role in reducing cancer risk and slowing tumor progression in physically active cancer survivors. Our aim was to provide the first detailed single cell transcriptomic analysis of exercise-mobilized lymphocytes and test their effectiveness as a donor lymphocyte infusion (DLI) in xenogeneic mice engrafted with human leukemia. Peripheral blood mononuclear cells (PBMCs) were collected from healthy volunteers at rest and at the end of an acute bout of cycling exercise. Flow cytometry and single-cell RNA sequencing was performed to identify phenotypic and transcriptomic differences between resting and exercise-mobilized cells using a targeted gene expression panel curated for human immunology. PBMCs were injected into the tail vein of xenogeneic NSG-IL-15 mice and subsequently challenged with a luciferase tagged chronic myelogenous leukemia cell line (K562). Tumor growth (bioluminescence) and xenogeneic graft-versus-host disease (GvHD) were monitored bi-weekly for 40-days. Exercise preferentially mobilized NK-cell, CD8+ T-cell and monocyte subtypes with a differentiated and effector phenotype, without significantly mobilizing CD4+ regulatory T-cells. Mobilized effector lymphocytes, particularly effector-memory CD8+ T-cells and NK-cells, displayed differentially expressed genes and enriched gene sets associated with anti-tumor activity, including cytotoxicity, migration/chemotaxis, antigen binding, cytokine responsiveness and alloreactivity (e.g. graft-versus-host/leukemia). Mice receiving exercise-mobilized PBMCs had lower tumor burden and higher overall survival (4.14E+08 photons/s and 47%, respectively) at day 40 compared to mice receiving resting PBMCs (12.1E+08 photons/s and 22%, respectively) from the same donors (p<0.05). Human immune cell engraftment was similar for resting and exercise-mobilized DLI. However, when compared to non-tumor bearing mice, K562 increased the expansion of NK-cell and CD3+/CD4-/CD8- T-cells in mice receiving exercise-mobilized but not resting lymphocytes, 1-2 weeks after DLI. No differences in GvHD or GvHD-free survival was observed between groups either with or without K562 challenge. Exercise in humans mobilizes effector lymphocytes with an anti-tumor transcriptomic profile and their use as DLI extends survival and enhances the graft-versus-leukemia (GvL) effect without exacerbating GvHD in human leukemia bearing xenogeneic mice. Exercise may serve as an effective and economical adjuvant to increase the GvL effects of allogeneic cell therapies without intensifying GvHD.

Clonal Kinetics and Single-Cell Transcriptional Profiles of T Cells Mobilized to Blood by Acute Exercise.

Acute exercise redistributes large numbers of memory T cells, which may contribute to enhanced immune surveillance in regular exercisers. It is not known, however, if acute exercise promotes a broad or oligoclonal T-cell receptor (TCR) repertoire or evokes transcriptomic changes in "exercise-responsive" T-cell clones. Healthy volunteers completed a graded bout of cycling exercise up to 80% V̇O 2max . DNA was extracted from peripheral blood mononuclear cells collected at rest, during exercise (EX), and 1 h after (+1H) exercise, and processed for deep TCR-β chain sequencing and tandem single-cell RNA sequencing. The number of unique clones and unique rearrangements was decreased at EX compared with rest ( P < 0.01) and +1H ( P < 0.01). Productive clonality was increased compared with rest ( P < 0.05) and +1H ( P < 0.05), whereas Shannon's Index was decreased compared with rest ( P < 0.05) and +1H ( P < 0.05). The top 10 rearrangements in the repertoire were increased at EX compared with rest ( P < 0.05) and +1H ( P < 0.05). Cross-referencing TCR-β sequences with a public database (VDJdb) revealed that exercise increased the number of clones specific for the most prevalent motifs, including Epstein-Barr virus, cytomegalovirus, and influenza A. We identified 633 unique exercise-responsive T-cell clones that were mobilized and/or egressed in response to exercise. Among these clones, there was an upregulation in genes related to cell death, cytotoxicity, and activation ( P < 0.05). Acute exercise promotes an oligoclonal T-cell repertoire by preferentially mobilizing the most dominant clones, several of which are specific to known viral antigens and display differentially expressed genes indicative of cytotoxicity, activation, and apoptosis.

Intramuscular lipid utilization during exercise: a systematic review, meta-analysis, and meta-regression.

Intramuscular lipid (IMCL) utilization during exercise was controversial as numerous studies did not observe a decline in IMCL content post-exercise when assessed in muscle biopsies using biochemical techniques. Contemporary techniques including immunofluorescence microscopy and 1H-magnetic resonance spectroscopy (1H-MRS) offer advantages over biochemical techniques. The primary aim of this systematic review, meta-analysis, and meta-regression was to examine the net degradation of IMCL in response to an acute bout of cycling exercise in humans, as assessed with different analytical approaches. A secondary aim was to explore the factors influencing IMCL degradation including feeding status, exercise variables, and participant characteristics. A total of 44 studies met the inclusion criteria using biochemical, immunofluorescence, and 1H-MRS techniques. A meta-analysis was completed using a random effects model and percentage change in IMCL content calculated from the standardized mean difference. Cycling exercise resulted in a net degradation of IMCL regardless of technique (total effect -23.7%, 95% CI = -28.7 to -18.7%) and there was no difference when comparing fasted versus fed-state exercise (P > 0.05). IMCL degradation using immunofluorescence techniques detected larger effects in type I fibers compared with whole muscle using biochemical techniques (P = 0.003) and in type I fibers compared with type II fibers (P < 0.001). Although IMCL degradation was associated with exercise duration, V̇o2max, and BMI, none of these factors independently related to the change in IMCL content. These findings provide strong evidence that the analytical approach can influence the assessment of IMCL degradation in human skeletal muscle in response to exercise.

Short-Term Oral Quercetin Supplementation Improves Post-exercise Insulin Sensitivity, Antioxidant Capacity and Enhances Subsequent Cycling Time to Exhaustion in Healthy Adults: A Pilot Study.

AimQuercetin has been reported to have antioxidant and anti-inflammatory properties on health promotion in human studies. The main purpose of this study was to investigate the effect of short-term oral quercetin supplementation on post-exercise whole-body energy metabolism. This study also aimed to determine the effects of supplementation on oxygen stress, inflammation, muscle damage, and high-intensity cycling exercise performance.MethodTwelve healthy participants, physically active students, were recruited to perform a randomized, single-blind crossover study. All subjects completed 7-days of quercetin (quercetin:1,000 mg per day for 7-days) and placebo supplementation in a randomized order. Supplement/placebo was combined with exercise consisting of 70% V̇O2max cycling for 60-min, followed by 3-h of recovery, then a subsequent single bout of cycling exercise with 75% V̇O2max to exhaustion. Time to exhaustion, indicators of muscle damage, as well as blood and gaseous parameters relating to energy metabolism, oxidative stress, inflammatory response, respectively, were determined.ResultsThe results showed that 7-day quercetin supplementation significantly attenuated the post-exercise glucose-induced insulin response, increased total antioxidant capacity (TAC) and superoxidase dismutase (SOD) activities, and mitigated malondialdehyde (MDA) levels during the recovery period (p < 0.05). While subsequent 75% V̇O2max cycling performance was significantly improved after quercetin treatment and accompanied by lower responses of interleukin 6 and creatine kinase at 24-h. However, it’s noted that there were no significant responses in glucose, respiratory exchange rate, tumor necrosis factor-α (TNF-α), myoglobin, and high sensitivity C-reactive protein between quercetin and placebo trials.ConclusionOur findings concluded that 7-day oral quercetin supplementation enhances high-intensity cycling time to exhaustion, which may be due in part to the increase in whole-body insulin-stimulated glucose uptake and attenuation of exercise-induced oxygen stress and pro-inflammation. Therefore, quercetin may be considered an effective ergogenic aid for enhancing high-intensity cycling performance among young adults.

The effects of exercise intensity and duration on the relationship between the slow component of V̇O2 and peripheral fatigue.

If the development of the oxygen uptake slow component (V̇O2SC ) and muscle fatigue are related, these variables should remain coupled in a time- and intensity-dependent manner. 16 participants (7 females) visited the laboratory on 7 separate occasions: (1) three 6-minutes moderate-intensity cycling exercise bouts proceeded by a ramp incremental test; (2-3) 30-minutes constant power output (PO) exercise bout to determine the maximal lactate steady state (MLSS); (4-7) constant-PO exercise bouts to task failure (TTF), pseudorandomized order, at (i) 15% below the PO at MLSS; (ii) 10W below MLSS; (iii) MLSS; (iv) 10W above MLSS (first intensity and randomized order thereafter). Neuromuscular fatigue was characterized by isometric maximal voluntary contractions and femoral nerve electrical stimulation of knee extensors to measure peripheral fatigue at baseline, at min 5, 10, 20, 30 and TTF. Pulmonary oxygen uptake (V̇O2 ) was continuously recorded during the constant-PO bouts and V̇O2SC was characterized based on each individual V̇O2 kinetics during moderate transitions. The development of V̇O2SC and peripheral fatigue were correlated across time (r2 adj range of 0.64-0.80) and amongst each exercise intensity (r2 adj range of 0.26-0.30) (all P<.001). Also, TTF was correlated with V̇O2SC and neuromuscular fatigue parameters (r2 adj range of 0.52-0.82, all P<.001). The V̇O2SC and peripheral fatigue development are correlated throughout the exercise in a time- and intensity-dependent manner, suggesting that the V̇O2SC may depend on muscle fatigue even if the mechanisms of reduced contractile function are different amongst intensities.

Pedaling cadence variability increases by worsening the bike fitting across most but not all workloads

Cyclic motion variability reflects the movement error correction. Since movement motor control generally worsens with impaired biomechanical setups, we assessed whether the pedaling cadence variability (PCV) increases by worsening the bike fitting across multiple workloads. Sixteen cyclists performed multiple 5-min bouts of constant load cycling exercise at 0, 20, 40, 55, 70, 85% of their maximum workload (MWL) capacity at 60 rpm with proper (PROPER) and worsened (WORSENED; 15 cm saddle height drop) bike fittings. Cycle-by-cycle duration series were collected. PCV was calculated as the standard deviation of each series. In both PROPER and WORSENED, PCV showed a U-shaped feature by increasing workload (minimum PCV values at 55% MWL). PCV was higher in WORSENED than PROPER, except at 55% MWL (0% MWL: 36.69 ± 10.06 vs. 42.21 ± 11.3, p &lt; 0.01; 55% MWL: 18.87 ± 3.51 vs. 19.74 ± 4.73, p = 0.3; 85% MWL: 34.93 ± 10.51 vs. 39.52 ± 11.84, p &lt; 0.01; ms; PROPER vs. WORSENED, respectively). PCV seems to be a workload-dependent variable, being greater at low and high workloads. At intermediate workloads, the moderate force expression to continue the movement, along with the effect of the workload itself in counteracting the natural extension of the leg, might explain a lower need for continuous motion adjustments and, consequently, a lower PCV in both bike setups.

Acute Response of Blood Lipids and Lipoproteins to Different Intensities of Exercise in Obese Males

This study aimed to examine the response of lipid and lipoprotein levels following different intensities of exercise in obese males. Fifteen obese (body mass index &gt; 30 kg/m2), sedentary (less than 2 days per week of physical activity) males, aged 18–30 years, participated in this randomized, cross-over study. The participants performed a single bout of cycling exercise (average energy expenditure: ~300 kcal) at two different intensities [lower-intensity: 50% of maximal heart rate and higher-intensity: 80% of maximal heart rate] in a random order. Overnight fasting blood samples were collected at baseline, immediately post-exercise (IPE), 1-hr PE, and 24-hr PE for each intensity of exercise to determine the profile of blood lipids and lipoproteins [total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)]. A 2(intensity) × 4(time) analysis of variance with repeated measures was used to examine the main and interaction differences in intensity and time on the profile of blood lipids and lipoproteins. The blood lipids and lipoproteins were not significantly altered following either lower or higher intensity exercise. There was no significant interaction between intensity and time. The results suggest that regardless of exercise intensity, an acute bout of aerobic exercise requiring 300 kcal energy expenditure may not be enough to significantly alter blood lipids and lipoproteins in physically healthy obese males. Therefore, it is recommended that future research determine whether different intensities of chronic exercise requiring the same or higher volume of energy expenditure can positively alter the blood lipid profiles in obese males.