Post-exercise Reduction Research Articles

Senolytic effects of exercise in human muscles require acute inflammation.

Higher intensity exercise, despite causing more tissue damage, improved aging conditions. We previously observed decreased p16INK4a mRNA in human skeletal muscle after high-intensity interval exercise (HIIE), with no change following equivalent work in moderate-intensity continuous exercise. This raises the question of whether the observed senolytic effect of exercise is mediated by inflammation, an immune response induced by muscle damage. In this study, inflammation was blocked using a multiple dose of ibuprofen (total dose: 1200 mg), a commonly consumed nonsteroidal anti-inflammatory drug (NSAID), in a placebo-controlled, counterbalanced crossover trial. Twelve men aged 20-26 consumed ibuprofen or placebo before and after HIIE at 120% maximum aerobic power. Multiple muscle biopsies were taken for tissue analysis before and after HIIE. p16INK4a+ cells were located surrounding myofibers in muscle tissues. The maximum decrease in p16INK4a mRNA levels within muscle tissues occurred at 3 h post-exercise (-82%, p < 0.01), gradually recovering over the next 3-24 h. A concurrent reduction pattern in CD11b mRNA (-87%, p < 0.01) was also found within the same time frame. Ibuprofen treatment attenuated the post-exercise reduction in both p16INK4a mRNA and CD11b mRNA. The strong correlation (r = 0.88, p < 0.01) between p16INK4a mRNA and CD11b mRNA in muscle tissues suggests a connection between the markers of tissue aging and pro-inflammatory myeloid differentiation. In conclusion, our results suggest that the senolytic effect of high-intensity exercise on human skeletal muscle is mediated by acute inflammation.

Interactive effects of exercise intensity and recovery posture on postexercise hypotension.

Postexercise reduction in blood pressure, termed postexercise hypotension (PEH), is relevant for both acute and chronic health reasons and potentially for peripheral cardiovascular adaptations. We investigated the interactive effects of exercise intensity and recovery postures (seated, supine, and standing) on PEH. Thirteen normotensive men underwent a V̇o2max test on a cycle ergometer and five exhaustive constant load trials to determine critical power (CP) and the gas exchange threshold (GET). Subsequently, work-matched exercise trials were performed at two discrete exercise intensities (10% > CP and 10% < GET), with 1 h of recovery in each of the three postures. For both exercise intensities, standing posture resulted in a more substantial PEH (all P < 0.01). For both standing and seated recovery postures, the higher exercise intensity led to larger reductions in systolic [standing: -33 (11) vs. -21 (8) mmHg; seated: -34 (32) vs. -17 (37) mmHg, P < 0.01], diastolic [standing: -18 (7) vs. -8 (5) mmHg; seated: -10 (10) vs. -1 (4) mmHg, P < 0.01], and mean arterial pressures [-13 (8) vs. -2 (4) mmHg, P < 0.01], whereas in the supine recovery posture, the reduction in diastolic [-9 (9) vs. -4 (3) mmHg, P = 0.08) and mean arterial pressures [-7 (5) vs. -3 (4) mmHg, P = 0.06] was not consistently affected by prior exercise intensity. PEH is more pronounced during recovery from exercise performed above CP versus below GET. However, the effect of exercise intensity on PEH is largely abolished when recovery is performed in the supine posture.NEW & NOTEWORTHY The magnitude of postexercise hypotension is greater following the intensity above the critical power in a standing position.

Efficacy and Safety of Mavacamten in the Treatment of Hypertrophic Cardiomyopathy: A Systematic Review.

Current pharmacological options for hypertrophic cardiomyopathy (HCM) are not disease-specific; while it treats symptoms, mavacamten targets the underlying pathology. We aim to assess the efficacy and safety of mavacamten, a first-in-class cardiac myosin inhibitor, in symptomatic obstructive HCM. This systematic review of the literature followed the PRISMA guidelines. Title/abstract and topics were searched using the following term: "mavacamten". The electronic research literature databases included the Cochrane Library, MedLine, and clinicaltrials.gov from July to August 2022. Primary efficacy endpoint was to assess clinical response at the end of treatment compared with baseline, defined as, at least one New York Heart Association (NYHA) class reduction. Two secondary endpoints from baseline were determined. The first was defined as improvement in mixed venous oxygen pressure (pVO2). The second was defined as reduction of the post-exercise left ventricular outflow tract (LVOT) gradient. We included in our analyses data from four studies that met our review eligibility criteria. There were three randomised placebo-controlled clinical trials and one non-randomised open-label clinical trial. All four studies showed a reduction in NYHA class from mavacamten use. Three out of four studies demonstrated >1 NYHA functional class improvement ranging from 34% to 80%, while only one study showed a smaller percentage of patients remaining at class 3. Three out of four studies measured pVO2 as an outcome, and all three studies noticed an increase in peak oxygen consumption after mavacamten treatment. Additionally, three out of four studies measured post-exercise LVOT gradient reduction as an outcome and all three found significant reduction in the post-exercise LVOT gradient after treatment. The most commonly observed adverse side effects were atrial fibrillation and decreased left ventricular ejection fraction, but all participants recovered without long-term sequelae and only one patient dropped out of the trial. Mavacamten has a greater efficacy than placebo in the treatment of HCM. It also showed promising tolerability and efficacy profiles in the treatment of HCM in adults. The three endpoints used in the evaluation of studies were reduction in NYHA class, increase in pVO2, and post-exercise LVOT gradient reduction. Mavacamten showed greater reduction in NYHA, larger effects on increase of pVO2, and significant reduction of the LVOT gradient. Mavacamten was also found to be well tolerated, like the placebo. The side effect profile was limited for the majority of individuals taking mavacamten. In the future, authors recommended dose-optimisation studies, and studies that evaluate mavacamten both in comparison to, and in conjunction with other current treatments.

Impact of traffic-related air pollution on the blood pressure response to exercise in individuals with hypertension

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): Natural Sciences and Engineering Research Council of Canada and B.C. Sports &amp; Exercise Medicine Research Foundation. Background The epidemiologic evidence suggests that the health benefits of exercise in healthy adults outweigh the adverse effects of air pollution in all but the most extreme concentrations. However, no studies have examined the acute response to exercise in air pollution in individuals with hypertension, a subgroup particularly susceptible to the cardiovascular effects of air population. Purpose The purpose of this study was to determine the impact of traffic-related air pollution on the acute cardiovascular response to exercise in patients with hypertension. We hypothesized that exposure to higher levels of traffic-related air pollution during exercise would attenuate, but not eliminate, acute post-exercise reductions in blood pressure and arterial stiffness. Methods Fourteen patients with hypertension (62.4±6.8 years; 81% male) completed a real-world, randomized, crossover study. Two 30-minute exercise bouts at 40-59% heart rate reserve were performed: once along a commercial street (high traffic) and once in an urban plaza (low traffic). Blood pressure (BP) and arterial stiffness (i.e., carotid-femoral pulse wave velocity [cfPWV]) were examined prior to, 30 minutes after, and 2 hours following exercise. 24-hour ambulatory BP monitoring was immediately completed following each visit. Black carbon, noise, relative humidity, and temperature were measured during each exercise bout (Figure 1). Results No differences were found for baseline cardiovascular measures between high and low traffic visits. At 30 minutes and 2 hours post-exercise, systolic BP was significantly reduced relative to baseline in the low-traffic condition only; diastolic BP was not significantly reduced at any timepoint. Based on linear mixed-effects analyses, exercising at the low traffic site was associated, relative to the high traffic site, with a significant (p = 0.04) reduction in systolic BP (-4.30 mm Hg [95% CI -8.09 to -0.54]) up to 2 hours following exercise after adjusting for exercise intensity, temperature, and noise; no differences were found for diastolic BP (-1.56 mm Hg [95% CI -4.87 to 1.83], p = 0.39). Each interquartile increase in black carbon (1168 ng/m³) was significantly associated with a 2.33 mm Hg (95% CI 0.37 to 4.17) increase in systolic BP up to 2 hours following exercise. No associations were observed between traffic site and BP for any ambulatory periods (i.e., 24-hour average, daytime, nighttime, or evening). The acute cfPWV response to exercise was also similar between traffic sites (p &amp;gt; 0.05). Conclusion Our findings suggest that exposure to traffic-related air pollution during exercise may adversely impact the beneficial short-term BP response to exercise in patients with hypertension. While the long-term implications of these changes to the acute BP response to exercise must be further explored, patients with hypertension can employ the prudent strategy of maximizing their distance from major roadways when exercising.

The effect of a pressure ventilatory support on quadriceps endurance is maintained after exercise training in severe COPD patients. A longitudinal randomized, cross over study.

Purpose: In severe chronic obstructive pulmonary disease (COPD) patients, the application of an inspiratory pressure support (IPS) during exercise increases exercise tolerance and the benefit of exercise training during pulmonary rehabilitation (PR). Moreover, it improves quadriceps endurance after a session of cycling exercise suggesting a reduced muscle fatigue. We looked for the persistence of this effect after PR and sought an association between the improved quadriceps endurance with IPS and the training load during PR. Patients and methods: We studied 20 patients with severe COPD (6 in stage 3and 14 in stage 4 of GOLD) before and after PR. As part of a PR program, patients completed 16 cycling sessions over 6 weeks with the addition of IPS during exercise. As a surrogate of muscular fatigue, quadriceps endurance was measured at 70% of maximal strength in a control condition, after a constant work rate exercise test (CWR) with IPS (TlimQ IPS) or with a sham ventilation (TlimQsham), in a random order. These tests were repeated similarly at the end of PR. Results: PR was associated with a significant increase in maximal power output, cycling endurance, quadriceps strength and endurance. Session training load (power output x duration of the session) increased by 142% during the course of the program. Before PR, CWR duration increases with IPS compared to sham ventilation (Δtime = +244s, p = 0.001). Compared to control condition, post-exercise TlimQ reduction was lower with IPS at isotime than at the end of CWR or than with sham ventilation (-9 ± 21%, -18 ± 16% and -23 ± 18%, respectively, p = 0.09, p < 0.0001 and p < 0.0001). After PR, the post-exercise decrease of TlimQ was reduced after IPS compared to sham (-9 ± 18% vs. -21 ± 17%, respectively, p = 0.004). No relationship was found between the prevention of quadriceps fatigue and the training load. Conclusion: In severe COPD patients, the beneficial effect of a ventilator support on quadriceps endurance persisted after PR with IPS. However, it was not related to the increase in training load, and could not predict the training response to non-invasive ventilation during exercise.

Impact of Exercise Training on Obstructive Sleep Apnea: A Systematic Review and Meta-analysis of Randomized Trials

ABSTRACT Background Randomized controlled trials have highlighted the importance of exercise training on the severity of obstructive sleep apnea (OSA). The primary objective of this meta-analysis was to analyze the data from these studies on the severity of OSA indices as measured by formal polysomnography. The secondary objective was to evaluate the effect of exercise on oxygen desaturation index, body mass index and several metabolic parameters associated with OSA. Methods Two independent reviewers and an experienced librarian searched MEDLINE, EMBASE, COCHRANE, and Scopus and SPORTDiscus databases from January 1, 2000, to October 21, 2021 to identify randomized controlled trials that evaluated the impact of exercise training on OSA severity. Pre-exercise and postexercise training data on the primary and secondary objectives were extracted. Results A total of 11 randomized controlled trials (533 study participants) were identified based on the inclusion criteria. The mean pre-exercise and postexercise reduction in apnea hypopnea index was −6.94 event per hour (95% confidence interval [CI]: −10.74 to −3.13, I2 = 84%). The mean changes in oxygen desaturation index and body mass index were −5.32 events per hour (95% CI: −9.65 to −0.99, I2 = 73%) and −1.21 kg·m−2 (95% CI: −1.80 to −0.62, I2 = 49%) respectively. Conclusion In adult patients with OSA, exercise training was associated with statistically significant reduction in OSA severity.

Influence Of Aerobic Exercise Intensity On Post-exercise Cerebrovascular Function

Peripheral vascular function is acutely improved, in an intensity dependent manner, following a single session of aerobic exercise. While previous studies have examined the effects of acute exercise on cerebrovascular function, the influence of exercise intensity on post-exercise cerebrovascular function remains unclear. PURPOSE: To determine the influence of aerobic exercise intensity on post-exercise cerebrovascular function. METHODS: Eleven participants (age: 27 ± 4 y; VO2max = 51 ± 8 mL/kg/min; men = 4, women = 7) completed 2 study days, in a randomized order, in which they either walked at 30% VO2max for 30 min (WALK) or ran at 70% VO2max for 30 min (RUN). Cerebrovascular reactivity to hypercapnia (CVR) was measured pre and 30 min post-exercise. Middle cerebral artery velocity (MCAv), mean arterial pressure (MAP), and end-tidal CO2 (ETCO2) were continuously monitored during the hypercapnia protocol. Cerebrovascular conductance index (CVCi) was calculated as MCAv/MAP. CVR was calculated as the slope between the percent changes in MCAv or CVCi and ETCO2. RESULTS: During WALK and RUN, there was no difference in MCAv from pre to post-exercise (p ≥ 0.05 for both), despite a significant post-exercise reduction in ETCO2 (WALK: pre = 42 ± 3 mmHg, post = 40 ± 2 mmHg; RUN: pre = 41 ± 3 mmHg, post = 40 ± 3 mmHg; p < 0.05 for both). While WALK had no significant change in MAP and CVCi from pre to post-exercise (p ≥ 0.05 for both), RUN had a significant decrease in MAP and increase in CVCi (MAP: pre = 95 ± 13 mmHg, post = 85 ± 8 mmHg; CVCi: pre = 0.67 ± 0.14 cm/s/mmHg, post = 0.80 ± 0.12 cm/s/mmHg; p < 0.05 for both). There was no significant change in MCAv CVR or CVCi CVR from pre to post-exercise for WALK (p ≥ 0.05 for both); however, there was a decline in both MCAv CVR and CVCi CVR from pre to post-exercise during RUN (MCAv CVR: pre = 1.7 ± 0.5 AU, post = 1.3 ± 0.4 AU; CVCi CVR: pre = 1.3 ± 0.5 AU, post = 0.9 ± 0.4 AU; p < 0.05 for both). Finally, there was no significant difference in the magnitude of change in MCAv CVR and CVCi CVR from pre to post-exercise between the study days (p ≥ 0.05 for both). CONCLUSION: Exercise intensity influences post-exercise cerebrovascular hemodynamics and function as RUN, but not WALK, had a significant increase in CVCi and a reduced MCAv CVR and CVCi CVR from pre to post-exercise. Supported by UW-Madison’s Fall Research Competition, NHLBI 118154

Caffeine ingestion increases endurance performance of trained male cyclists when riding against a virtual opponent without altering muscle fatigue.

Caffeine improves cycling time trial (TT) performance; however, it is unknown whether caffeine is ergogenic when competing against other riders. The aim of this study was to investigate whether caffeine improves performance during a 4-km cycling TT when riding against a virtual opponent, and whether it is associated with increased muscle activation and at the expense of greater end-exercise central and peripheral fatigue. Using a randomized, crossover, and double-blind design, eleven well-trained cyclists completed a 4-km cycling TT alone without supplementation (CON), or against a virtual opponent after ingestion of placebo (OP-PLA) or caffeine (5mg.kg-1, OP-CAF). Central and peripheral fatigue were quantified via the pre- to post-exercise decrease in voluntary activation and potentiated twitch force, respectively. Muscle activation was continually measured during the trial via electromyography activity. Compared to CON, OP-PLA improved 4-km cycling TT performance (P = 0.018), and OP-CAF further improved performance when compared to OP-PLA (P = 0.050). Muscle activation was higher in OP-PLA and OP-CAF than in CON throughout the trial (P = 0.003). The pre- to post-exercise reductions in voluntary activation and potentiated twitch force were, however, similar between experimental conditions (P > 0.05). Compared to CON, OP-PLA increased the rating of perceived exertion during the first 2km, but caffeine blunted this increase with no difference between the OP-CAF and CON conditions. Caffeine is ergogenic when riding against a virtual opponent, but this is not due to greater muscle activation or at the expense of greater end-exercise central or peripheral fatigue.

Influence of Cognitive Challenges During Exercise on Post‐Exercise Cerebrovascular Function

Peripheral vascular function is acutely improved following a single session of aerobic exercise. This improvement is likely due to increased blood flow during aerobic exercise. Cognitive activity and aerobic exercise both acutely increase cerebral blood flow, and while previous studies have examined the influence of acute exercise on post‐exercise cerebrovascular function, the effects of increased cognitive activity during exercise on post‐exercise cerebrovascular function remains unclear. Therefore, the purpose of this study was to examine the influence of increased cognitive activity during aerobic exercise on post‐exercise cerebrovascular function. We hypothesized that performing cognitive challenges during exercise would result in greater post‐exercise cerebrovascular function. METHODS: Ten participants (age: 27 ± 5 y; VO2max = 53 ± 10 mL/kg/min; men = 5, women = 5) completed 2 study days, in a randomized order, in which they either walked at 30% VO2max for 30 min (WALK) or walked at 30% VO2max for 30 min while completing N‐back cognitive tasks (WALK+COG). Cerebrovascular reactivity to hypercapnia (CVR) was measured pre‐ and 90 min post‐exercise as a measure of cerebrovascular function. Middle cerebral artery velocity (MCAv), mean arterial pressure (MAP), and end‐tidal CO2 (ETCO2) were continuously monitored during the hypercapnia protocol. Cerebrovascular conductance index (CVCi) was calculated as MCAv/MAP. CVR was calculated as the slope between the changes in MCAv or CVCi and ETCO2. RESULTS: During WALK and WALK+COG, there was no difference in MCAv from pre‐ to post‐exercise (p ≥ 0.05 for both), despite a significant post‐exercise reduction in ETCO2 (WALK: pre = 43 ± 2 mmHg, post = 41 ± 3 mmHg; WALK+COG: pre = 41 ± 4 mmHg, post = 40 ± 3 mmHg; p &lt; 0.05 for both). While WALK had no significant change in MAP from pre‐ to post‐exercise (p = 0.10), WALK+COG had a significant increase in MAP (pre = 88 ± 18 mmHg, post = 98 ± 14 mmHg; p = 0.01). Both WALK and WALK+COG had a decrease in CVCi from pre‐ to post‐exercise (WALK: pre = 0.70 ± 0.15 cm/s/mmHg, post = 0.65 ± 0.17 cm/s/mmHg; WALK+COG: pre = 0.75 ± 0.15 cm/s/mmHg, post = 0.66 ± 0.14 cm/s/mmHg; p &lt; 0.05 for both). There was no significant change in CVR from pre‐ to post‐exercise during either study days (assessed as MCAv or CVCi; p ≥ 0.05 for both). Finally, there was no significant difference in the magnitude of change in CVR from pre‐ to post‐exercise between the study days (assessed as MCAv or CVCi; p ≥ 0.05 for both). CONCLUSION: Cognitive challenges during exercise did not influence post‐exercise cerebrovascular function. Despite this finding, cognitive challenges during walking may influence resting systemic hemodynamics, as it resulted in an increased post‐exercise MAP compared with walking alone.

The effect of insulin on post-exercise hypoglycemia in adults with type 2 diabetes participating in outpatient exercise-based cardiac rehabilitation.

Few studies have reported on self-monitored blood glucose changes following acute exercise, particularly in patients with type 2 diabetes prescribed oral sulfonylureas and insulin medication. This study sought to determine the magnitude of post-exercise blood glucose changes and incidence of hypoglycemia (blood glucose < 4.0mmol/L) in relation to medication regimen. A retrospective chart review was conducted in adults with type 2 diabetes attending a 6-month rehabilitation program. Demographics, medications, exercise prescription and patient-reported pre/post-BG values were collected at program initiation. It was hypothesized that patients with type 2 diabetes will experience a post-exercise capillary blood glucose reduction (ΔcapBG), and that incidents of hypoglycemia (< 4.0mmol/L) will be strongly associated with insulin or oral secretagogue class of medication. A chart review was conducted (n = 52, 46.2% males, mean age: 62.7 ± 8.3years, A1c: 7.7 ± 1.6%, body mass index, BMI: 34.4 ± 7.8kg/m2) in patients with type 2 diabetes (9.0 ± 7.7years since diagnosis). A greater reduction in BG was related to a greater pre-exercise BG (beta [95% CI]: -0.46 [-0.54, -0.37] mmol, p < 0.0001), independent of BMI and exercise duration. Post-exercise hypoglycemia (< 4.0mmol) was associated with prescribed insulin use (vs. non-users: 14.5% vs. 3.0%, p < 0.05). Among insulin users, pre-mixed insulin had the highest incidence of hypoglycemia (vs. non-users: 50% vs. 3%, p < 0.0001) and insulin (bolus and basal; vs. non-users: 11.1% vs. 3%, p = 0.04). These findings may suggest a low post-exercise hypoglycemia occurrence in patients with type 2 diabetes, except when taking insulin. Self-management strategies should be considered, especially for patients on insulin medications.

Walking-induced endothelial dysfunction predicts ischemic cardiovascular events in patients with intermittent claudication.

Endothelial dysfunction, evaluated by flow-mediated dilatation (FMD), predicts adverse cardiovascular events in patients with intermittent claudication (IC). IC is an example of repeated ischemia/reperfusion injury that may contribute to the progression of vascular disease by worsening endothelial function, a trigger for acute cardiovascular events. The predictive value of effort-induced endothelial dysfunction for cardiovascular events in patients with IC has not been studied previously. The objective of this study was to assess whether exercise-induced endothelial dysfunction is predictive of adverse cardiovascular outcome in IC. In 44 patients with IC, we measured brachial artery FMD by B-mode ultrasonography at rest and 10 minutes after a maximal treadmill exercise. Treadmill exercise halved the FMD (from 3.5 ± 0.6% to 1.45 ± 0.46%, p < 0.05). After a follow-up period of 85 (72-98) months, a total of 20 major cardiovascular events occurred. In a multivariate analysis, a post-exercise reduction of brachial FMD > 1.3% was predictive for cardiovascular events. Maximal exercise-induced endothelial dysfunction is predictive of cardiovascular events in patients with IC.

Does the Nutritional Composition of Dairy Milk Based Recovery Beverages Influence Post-exercise Gastrointestinal and Immune Status, and Subsequent Markers of Recovery Optimisation in Response to High Intensity Interval Exercise?

This study aimed to determine the effects of flavored dairy milk based recovery beverages of different nutrition compositions on markers of gastrointestinal and immune status, and subsequent recovery optimisation markers. After completing 2 h high intensity interval running, participants (n = 9) consumed a whole food dairy milk recovery beverage (CM, 1.2 g/kg body mass (BM) carbohydrate and 0.4 g/kg BM protein) or a dairy milk based supplement beverage (MBSB, 2.2 g/kg BM carbohydrate and 0.8 g/kg BM protein) in a randomized crossover design. Venous blood samples, body mass, body water, and breath samples were collected, and gastrointestinal symptoms (GIS) were measured, pre- and post-exercise, and during recovery. Muscle biopsies were performed at 0 and 2 h of recovery. The following morning, participants returned to the laboratory to assess performance outcomes. In the recovery period, carbohydrate malabsorption (breath H2 peak: 49 vs. 24 ppm) occurred on MBSB compared to CM, with a trend toward greater gut discomfort. No difference in gastrointestinal integrity (i.e., I-FABP and sCD14) or immune response (i.e., circulating leukocyte trafficking, bacterially-stimulated neutrophil degranulation, and systemic inflammatory profile) markers were observed between CM and MBSB. Neither trial achieved a positive rate of muscle glycogen resynthesis [−25.8 (35.5) mmol/kg dw/h]. Both trials increased phosphorylation of intramuscular signaling proteins. Greater fluid retention (total body water: 86.9 vs. 81.9%) occurred on MBSB compared to CM. Performance outcomes did not differ between trials. The greater nutrient composition of MBSB induced greater gastrointestinal functional disturbance, did not prevent the post-exercise reduction in neutrophil function, and did not support greater overall acute recovery.

Comparison Of Glycemic Behavior Between Strength Training, HighIntensity Resistance Training (Hirt), High Intensity Interval Training (Hiit):A Case Study

Type 2 Diabetes Mellitus (DM 2) is generally a defect in insulin action and secretion and in the regulation of hepatic glucose production. Exercise to treat type 2 diabetes has had positive impacts on the lives of diabetics. The aim of this study is to analyze the effects of the glycemic curve in three different types of training: Strength Training (TF), High Intensity Resistance Training (HIRT) and Interval High Intensity Training (HIIT). The participantis a 57yearold, sedentary type 2 diabetic who under went the training method - Strength Training (ST) 60% of repetition maximum (RM), 8 to 12 repetitions, cadence 2010, the 2-minute restinterval. High Intensity Resistance Training (HIRT)protocol consisted of three sets with six repetitions at 80% of 1RM followed by rest for 20 seconds, the individual performs another series with the same load until reaching the point of failure again. The rest of one exercises and another is 2’30” , and High IntensityInterval Training (HIIT) a 5-minute warm-upmoderateload – 4 shots of 30 secondsof high intensity duration separated by 4 minutes of rest, once a week at night. Pre-study anamnesis, pre- and post-exercise glycemia were performed.The overall results were satisfactory presenting HIIT as the most effective method for acute post-exercise blood glucose reduction (reducing 29.62%, 34.25%, 38.89 and 36.11% immediatelyat 10, 20, 30 minutes afterexertionrespectively).It was concluded that physical training positively influenced the reduction of blood glucose as an acute effect, but HIIT was the most effective method.

Effects of Eccentric Cycling Performed at Long vs. Short Muscle Lengths on Heart Rate, Rate Perceived Effort, and Muscle Damage Markers.

Peñailillo, L, Aedo, C, Cartagena, M, Contreras, A, Reyes, A, Ramirez-Campillo, R, Earp, JE, and Zbinden-Foncea, H. Effects of eccentric cycling performed at long vs. short muscle lengths on heart rate, rate perceived effort, and muscle damage markers. J Strength Cond Res 34(10): 2895-2902, 2020-It is possible that the magnitude of muscle damage in eccentric cycling is dependent on seat position that could affect the muscle length changes during eccentric contractions. However, no previous study has investigated the effect of seat position on muscle damage and metabolic demand in eccentric exercise. Thus, this study compared 2 seating positions; seat forward in which knee extensor muscles were stretched longer (LONG) and seat back in which the muscles were stretched shorter (SHORT). Young men performed 30 minutes of eccentric cycling at 80% of maximal concentric power output at either LONG (n = 10) or SHORT (n = 10) condition. Heart rate and rate perceived effort (RPE) during exercise, changes in maximal voluntary isometric contraction (MVC) strength of the knee extensors, muscle soreness assessed by a visual analog scale (VAS), and pressure-pain threshold (PPT) before, immediately after, and 24-72 hours after exercise were compared between conditions. Heart rate and RPE were significantly greater in LONG than SHORT group (9.5 and 19.0%, respectively). Post-exercise reduction in MVC was 8.4-14.0% greater in LONG than SHORT group from immediately after to 48 hours after exercise. In addition, VAS was greater in LONG than SHORT group from 48 to 72 hours after exercise, and vastus medialis PPT was greater in SHORT than LONG group from 24 to 72 hours after exercise (p < 0.05). These results suggest that muscle damage and metabolic demand are greater when seat is set back than forward. Thus, when prescribing eccentric cycling to individuals who are unaccustomed to eccentric cycling, it is better to set the seat far from the pedals.

Neuromuscular responses to fatiguing locomotor exercise.

Over the last two decades, an abundance of research has explored the impact of fatiguing locomotor exercise on the neuromuscular system. Neurostimulation techniques have been implemented prior to and following locomotor exercise tasks of a wide variety of intensities, durations, and modes. These techniques have allowed for the assessment of alterations occurring within the central nervous system and the muscle, while techniques such as transcranial magnetic stimulation and spinal electrical stimulation have permitted further segmentalization of locomotor exercise-induced changes along the motor pathway. To this end, the present review provides a comprehensive synopsis of the literature pertaining to neuromuscular responses to locomotor exercise. Sections of the review were divided to discuss neuromuscular responses to maximal, severe, heavy and moderate intensity, high-intensity intermittent exercise, and differences in neuromuscular responses between exercise modalities. During maximal and severe intensity exercise, alterations in neuromuscular function reside primarily within the muscle. Although post-exercise reductions in voluntary activation following maximal and severe intensity exercise are generally modest, several studies have observed alterations occurring at the cortical and/or spinal level. During prolonged heavy and moderate intensity exercise, impairments in contractile function are attenuated with respect to severe intensity exercise, but are still widely observed. While reductions in voluntary activation are greater during heavy and moderate intensity exercise, the specific alterations occurring within the central nervous system remain unclear. Further work utilizing stimulation techniques during exercise and integrating new and emerging techniques such as high-density electromyography is warranted to provide further insight into neuromuscular responses to locomotor exercise.

The Effect Of Exercise Intensity On The Development Of Diaphragm And Expiratory Abdominal Muscle Fatigue

Exhaustive high-intensity exercise (85-95% of V̇O2peak) elicits respiratory muscle fatigue, likely due to a high work of breathing (WoB) combined with a competition for available cardiac output (Q̇). However, the WoB associated with submaximal heavy-intensity exercise (≤75% V̇O2peak) makes insufficient demands for V̇O2 and Q̇ to engender a substantial competition for available blood flow. Whether the respiratory muscles fatigue in response to exhaustive heavy-intensity exercise remains unclear. PURPOSE: To investigate the effect of exercise intensity on the presence and severity of exercise-induced diaphragm and expiratory muscle fatigue in healthy humans. METHODS: Ten healthy adults (25 ± 3 y, 3 females) performed a ‘ramp sprint’ test to determine critical power (CP), peak ramp power (Ppeak) and V̇O2peak (54 ± 9 ml/kg/min). The subjects then performed two constant-power cycling tests to exhaustion: 1) 5% < CP (173 ± 50 W, heavy intensity); 2) ~25% of the difference between CP and Ppeak (215 ± 53 W, severe intensity). Diaphragm and expiratory muscle fatigue were quantified as the pre- to post-exercise reduction in the transdiaphragmatic (Pditw) and gastric (Pgatw) twitch pressure response to magnetic stimulation of the cervical and thoracic nerves, respectively. RESULTS: Exercise time was longer for heavy vs. severe exercise (36 ± 6 vs. 10 ± 3 min, P < 0.05). Final min V̇O2 was lower during heavy (3.12 ± 0.74 L/min; 82 ± 5% of V̇O2peak) vs. severe exercise (3.60 ± 0.83 L/min; 95 ± 4% of V̇O2peak) (P < 0.05). Both heavy and severe exercise elicited a significant reduction in Pditw (−13 ± 11% and -19 ± 13%) and Pgatw (−23 ± 20% vs. -24 ± 17%) (both P < 0.05); however, the magnitude of exercise-induced respiratory muscle fatigue was not different between trials (P > 0.05). The cumulative diaphragm and gastric pressure-time products were greater for heavy vs. severe exercise (PTPdi: 16790 ± 6727 vs. 5945 ± 1956 cmH2O/s; PTPga: 7818 ± 3368 vs. 2595 ± 1233 cmH2O/s; both P < 0.05). CONCLUSION: The diaphragm and expiratory muscles fatigue in response to exhaustive heavy- and severe-intensity exercise in healthy humans. The magnitude of exercise-induced respiratory muscle fatigue between trials was not different despite a substantially greater cumulative PTPdi and PTPga for heavy- vs. severe-intensity exercise.

Blueberry and Banana Consumption Mitigate Arachidonic, Cytochrome P450 Oxylipin Generation During Recovery from 75-Km Cycling

Abstract Objectives Oxylipins are bioactive lipid oxidation products that have vital regulatory roles in numerous physiological processes including inflammation. This study determined if 2-weeks blueberry and/or acute banana ingestion influenced generation of in n-6 and n-3 PUFA-derived oxylipins during recovery from a 75-km cycling time trial. Methods Cyclists (n = 59, 38.6 ± 1.5 years of age) were randomized to freeze-dried blueberry or placebo groups, and ingested 26 grams/d (1 cup/d fresh blueberries equivalent) for 2 weeks. Cyclists reported to the lab in an overnight fasted state and engaged in a 75-km cycling time trial (185.5 ± 5.2 min). Cyclists from each group (blueberry, placebo) were further randomized to ingestion of water-only or water with Cavendish bananas (carbohydrate intake, 0.2 g/kg every 15 min) during exercise. Blood samples were collected pre- and post-2- weeks supplementation, and then 0 h-, 1.5 h-, 3 h-, 5 h-, 24 h-, 48 h-post-exercise. Plasma oxylipins and phenolic blueberry and banana metabolites were measured with ultra-performance liquid chromatography-tandem mass spectrometer (UPLC–MS/MS) using reference standards. Results Significant time × treatment effects (8 time points, 4 groups) were found for 24 blueberry-related and seven banana-related gut-derived metabolites in plasma (fdr P-value &amp;lt; 0.05). Significant and substantial post-exercise increases were measured for 64 of 67 identified plasma oxylipins. Oxylipins were grouped according to relevant fatty acid substrates [arachidonic acid (ARA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), α-linolenic acid (ALA), linoleic acid (LA), and enzyme systems [cytochrome P450 (CYP), lipoxygenase (LOX)]. Banana and blueberry ingestion were independently associated with significant post-exercise reductions in pro-inflammatory ARA-CYP HETEs and DiHETrEs (treatment effect, fdr P-value = 0.003). These trial differences were especially apparent within the first three hours of recovery from the 75-km cycling bout. Conclusions Prolonged and intensive exercise evoked a transient but robust increase in plasma levels of oxylipins, with a strong attenuation effect of ARA-CYP oxylipins linked to acute carbohydrate intake from bananas and 2-weeks ingestion of blueberries. Funding Sources Dole Foods, Westlake Village, CA.

Caffeine increases peripheral fatigue in low- but not in high-performing cyclists.

The influence of cyclists' performance levels on caffeine-induced increases in neuromuscular fatigue after a 4-km cycling time trial (TT) was investigated. Nineteen cyclists performed a 4-km cycling TT 1 h after ingesting caffeine (5 mg·kg-1) or placebo (cellulose). Changes from baseline to after exercise in voluntary activation (VA) and potentiated 1 Hz force twitch (Qtw,pot) were used as markers of central and peripheral fatigue, respectively. Participants were classified as "high performing" (HP, n = 8) or "low performing" (LP, n = 8) in accordance with their performance in a placebo trial. Compared with placebo, caffeine increased the power, anaerobic mechanical power, and anaerobic work, reducing the time to complete the trial in both groups (p < 0.05). There was a group versus supplement and a group versus supplement versus trial interaction for Qtw,pot, in which the postexercise reduction was greater after caffeine compared with placebo in the LP group (Qtw,pot = -34% ± 17% vs. -21% ± 11%, p = 0.02) but not in the HP group (Qtw,pot = -22% ± 8% vs. -23% ± 10%, p = 0.64). There was no effect of caffeine on VA, but there was a group versus trial interaction with lower postexercise values in the LP group than in the HP group (p = 0.03). Caffeine-induced improvement in 4-km cycling TT performance seems to come at the expense of greater locomotor muscle fatigue in LP but not in HP cyclists. Novelty Caffeine improves exercise performance at the expense of a greater end-exercise peripheral fatigue in low-performing athletes. Caffeine-induced improvement in exercise performance does not affect end-exercise peripheral fatigue in high-performing athletes. High-performing athletes seem to have augmented tolerance to central fatigue during a high-intensity time trial.

RELACIÓN ENTRE VFC POST-EJERCICIO Y LA CARGA INTERNA DE ENTRENAMIENTO EN TRIATLETAS

The aim of the study was to stablish relationships between post-exercise heart rate variability (HRV) values and internal training load (TL) components measured by three Training Impulse (TRIMP) methods in youth triathletes. TRIMP methods were related with each other (r = 0,970 to 0,983, R2 = 0,940 to 0,967) but showed significant differences in mean values (p 90% HRres, and TRIMP values (r = -0,302 to -0,495, p < 0,01) and a positive relationship with volume at <50% HRres (r = 0.488, p < 0,01). Immediate post-exercise HRV reduction can provide valuable information for evaluation of physiological effects at intervallic or continuous training in youth triathletes.

Exercise heat acclimation causes post-exercise hypotension and favorable improvements in lipid and immune profiles: A crossover randomized controlled trial

Passive hyperthermic exposure causes an acute hypotensive response following the cessation of heat stress. Chronic heat stress is well documented in animal studies to instigate metabolic and lipid alterations. However, it is unknown if exercise-heat acclimation also causes favorable chronic blood pressure, lipid, and immune responses in humans. This project tested the hypothesis that 10-day exercise-heat acclimation (HA) would cause greater post-exercise reductions in arterial blood pressure and favorable metabolic, lipid, and immune responses compared to 10-day exercise under neutral conditions (CON). Thirteen healthy sedentary participants (8M/5F, 28 ± 6y, 78 ± 17 kg), completed a 10-day (90 min/day exercise bout) clamped hyperthermia HA (increase internal temperature 1.5 °C, in 42 °C, 28% Rh) and control (CON: 23 °C, 42% Rh) protocols in a counterbalanced design with a 2 month washout. Pre- and post-exercise HA/CON blood pressures were taken 1-h post-exercise on exercise days 1 and 10. Metabolic, lipid and immune panels were taken pre-post HA/CON. Exercise under heat stress had greater post-exercise hypotension (systolic; -6 mmHg, diastolic; -8 mmHg; and mean arterial pressure; -7 mmHg) on both days 1 and 10 compared to exercise under neutral conditions (main effect for condition, P ≤ 0.004). Only from pre-to-post HA, total cholesterol (168 ± 19 to 157 ± 15; P < 0.03) and triglycerides (137 ± 45 to 111 ± 30; P < 0.03) were reduced, while absolute lymphocytes (-26%), monocytes (-22%), and basophils (-49%) significantly decreased (each P ≤ 0.04). Relative values of neutrophils increased (18%) and lymphocytes decreased (-20%) only after HA (P ≤ 0.04). These data indicate that exercise in the heat (regardless of acclimation status) causes a profound post-exercise hypotensive response, while HA causes favorable lipid, and immune profile changes. Further examination of exercise-heat acclimation on vascular, metabolic, and immune responses will offer insight for benefits in other clinical populations with vascular, metabolic and immune dysfunction.