High-intensity Exercise Protocol Research Articles

Acute Inflammatory Response to Eccentric Exercise in Young and Master Resistance-trained Athletes.

This study aimed to compare the acute inflammatory response following high-intensity eccentric exercise between resistance-trained young and master athletes with similar performance levels. Resistance-trained young (n=8; 22±2 years) and master (n=8; 52±4 years) male athletes of a similar performance level performed a standardized high-intensity eccentric squat exercise protocol (10 sets of half-squats at 70% of 1-repetition maximum). The serum concentration of 20 biomarkers related to tissue damage, inflammation, remodeling, and repair was measured at baseline, immediately after exercise, and over a 72 h recovery period. Both groups experienced similar muscle damage as evidenced by a comparable increase in creatine kinase activity 24 h after exercise (p<0.001). Interleukin-6 (p=0.009) and growth hormone (p<0.001) increased immediately post-exercise in both groups. Monocyte chemoattractant protein-1 increased immediately post-exercise only in young athletes (p=0.003) and then decreased 24 h later. There were no significant differences for the remaining variables, including cell markers related to neutrophil/macrophage activation or pro/anti-inflammatory cytokines. Resistance-trained young and master athletes, matched for performance level, showed an overall similar inflammatory response to eccentric exercise, possibly reflecting regulatory mechanisms or immunological adaptations to chronic stimulation in master athletes.

Cycle-based high-intensity sprint exercise elicits acute cognitive dysfunction in psychomotor and memory task performance

PurposeTo examine the impact of an acute high-intensity sprint exercise protocol (HISEP) for eliciting post-exercise cognitive dysfunction in psychomotor, attentional, executive, and memory tasks.MethodsTwenty-four recreationally active adults (22 ± 4 yrs, 169.39 ± 10.07 cm, 75.80 ± 14.73 kg, 27.03 ± 9.55 BF%) performed a HISEP on a cycle ergometer. Average psychomotor reaction time (avgRT; Dynavision D2 Mode A &amp;amp; Mode B), mood (Profile of Mood States Questionnaire; POMS), and cognition (Automated Neuropsychological Assessment Metrics; ANAM) were assessed pre- (PRE), post- (POST) and 60-min post (60POST) HISEP. One-way repeated measures ANOVAs were used to assess changes across time.ResultsFatigue (main effect: p &amp;lt; 0.001, ηp2 = 0.309) was significantly higher at POST compared to PRE (p = 0.007). Tension (main effect: p = 0.021, ηp2 = 0.154) was significantly lower at 60POST compared to PRE (p = 0.029). Mode A avgRT (main effect: p = 0.022, ηp2 = 0.153) was significantly slower at POST compared to PRE (p = 0.026). Throughput (TP) scores for ANAM code substitution-delayed (CSD) task (main effect: p &amp;lt; 0.001, ηp2 = 0.284) and matching to sample (M2S) tasks (main effect: p = 0.014, ηp2 = 0.169) were significantly lower at POST compared to PRE (p = 0.001 and p = 0.025, respectively), while mathematical processing (main effect: p = 0.002, ηp2 = 0.232) was significantly higher at 60POST compared to both PRE (p = 0.019) and POST (p = 0.005). No other significant changes in cognitive task performance were observed (p's &amp;gt; 0.05).ConclusionsThe HISEP is a feasible and time-effective fatiguing exercise stimulus capable of eliciting acute cognitive dysfunction in psychomotor and memory task performance. NCT05100589.

Exercise, mTOR Activation, and Potential Impacts on the Liver in Rodents.

The literature offers a consensus on the association between exercise training (ET) protocols based on the adequate parameters of intensity and frequency, and several adaptive alterations in the liver. Indeed, regular ET can reverse glucose and lipid metabolism disorders, especially from aerobic modalities, which can decrease intrahepatic fat formation. In terms of molecular mechanisms, the regulation of hepatic fat formation would be directly related to the modulation of the mechanistic target of rapamycin (mTOR), which would be stimulated by insulin signaling and Akt activation, from the following three different primary signaling pathways: (I) growth factor, (II) energy/ATP-sensitive, and (III) amino acid-sensitive signaling pathways, respectively. Hyperactivation of the Akt/mTORC1 pathway induces lipogenesis by regulating the action of sterol regulatory element binding protein-1 (SREBP-1). Exercise training interventions have been associated with multiple metabolic and tissue benefits. However, it is worth highlighting that the mTOR signaling in the liver in response to exercise interventions remains unclear. Hepatic adaptive alterations seem to be most outstanding when sustained by chronic interventions or high-intensity exercise protocols.

If You Give a Mouse a Cookie: Quantification of Metabolic and Neurologic Changes in Murine Model for Charcot Arthropathy

Category: Basic Sciences/Biologics; Diabetes Introduction/Purpose: Charcot arthropathy (Charcot) is a significant complication of diabetes mellitus thought to occur as a result of repetitive microtrauma to the insensate foot. We previously developed a murine model of diet-induced obese mice with peripheral neuropathy which underwent a high-intensity treadmill protocol designed to induce metabolic, neurologic, radiographic, and histopathologic features similar to Charcot in humans. Using this model, we aimed to further characterize the metabolic and sensory changes that occur in these diet-induced obese mice subjected to various high-intensity exercise protocols designed to induce repetitive microtrauma to the hind paws similar to Charcot. Methods: Forty-nine wild-type C57BL/6J mice were randomized to receive either a standard or high-fat diet and exposed to a high-intensity treadmill running protocol for various lengths of time as described in Figure 1A. Group 1 received a standard low-fat (10% kcal from fat) mouse diet and did not participate in the treadmill protocol. Groups 2, 3, 4, and 5 were fed a high-fat (60% kcal from fat) diet ad libidum to facilitate diet-induced obesity (DIO) and completed the treadmill protocol for various lengths of time. Initial body weights, DEXA scans, hind-paw Von-Frey filament sensory testing, and hot plate sensory testing following the previously published murine model were performed prior to the start of the running protocol and repeated at weeks 4, 8, 12, and 16. Plantar temperatures were measured initially and at 16 weeks. Paired-t-Test and one-way ANOVA were utilized to determine the significance of observed results. Results: Bodyweights are represented in Figure 1B. Plantar temperature was not significantly different between treadmill running groups at week 0 or 16 (Figure 1C). Hot plate testing demonstrated no significant difference in the number of responses between groups at week 0. By week 16, groups 3 and 5 demonstrated decreased hind-paw sensitivity to hot plate testing, suggestive of decreased sensation. Von Frey sensory testing also showed more force was required to induce a positive response, indicating decreased hind-paw sensation in high-fat diet groups (Figure 1D). By weeks 12 and 16, high-fat diet groups had significantly higher fasting blood glucose levels than group 1(Figure 1E). Additionally, high-fat diet groups demonstrated a significantly higher body fat percentage and lower bone mineral density (BMD) at weeks 0 and 16. Conclusion: Decreased sensitivity to hot plate and Von Frey testing demonstrate decreased sensation in the hind paws of DIO mice fed a high-fat diet. DIO mice also have significantly higher fasting blood glucose levels than mice fed a regular diet indicating impaired glucose tolerance. These metabolic and sensory changes suggest this is a reliable murine model of diabetic neuropathy. This model of diabetic neuropathy provides an avenue to study the radiographic and histologic changes that occur in these mice when exposed to repetitive exercise-induced microtrauma similar to Charcot arthropathy in humans.

Landing Posture in Elite Female Athletes During a Drop Vertical Jump Before and After a High-Intensity Ergometer Fatigue Protocol: A Study of 20 Japanese Women’s Soccer League Players

Background: Even elite athletes, who usually show stable postural control, sometimes cannot control their posture after high-load training. This instability may contribute to anterior cruciate ligament injury. Purpose/Hypothesis: The purpose of this study was to evaluate the landing posture of elite female soccer players before and after a novel high-intensity fatigue-inducing exercise protocol. We hypothesized that the landing posture will change before versus after the fatigue protocol. Study Design: Descriptive laboratory study. Method: The study participants were 20 female elite soccer players. All athletes performed 3 drop vertical jumps (DVJs), pedaled an ergometer 8 times with full force for 10 seconds each (fatigue protocol), and then repeated the 3 DVJs. We measured and compared the athletes’ blood lactate levels before and after the fatigue protocol, as well as the hip flexion, knee flexion, and ankle dorsiflexion angles and final landing posture during the DJVs. Results: Blood lactate levels increased significantly pre- to postprotocol (from 2.7 ± 1.9 to 15.0 ± 3.6 mmol/L; P &lt; .001), while there were decreases in hip flexion angle (from 35.0° ± 11.2° to 22.4° ± 8.8°; P &lt; .001) and ankle dorsiflexion angle (from 26.4° ± 3.9° to 20.0° ± 3.7°; P &lt; .001). The number of athletes who could not maintain a stable DVJ final landing posture increased from 10% before the fatigue protocol to 70% after. Conclusion: The elite female athletes in our study showed significant decreases in hip flexion and ankle dorsiflexion angles in the DVJ landing after a fatigue-inducing protocol. Most elite athletes were unable to maintain a stable posture on the DVJ landing after the fatigue protocol. Clinical Relevance: This study advances our understanding of how elite athletes land in a fatigued state.

Acute effect of moderate and high-intensity interval exercises on asprosin and BDNF levels in inactive normal weight and obese individuals

This study aimed to examine the acute effects of moderate-intensity aerobic and high-intensity interval exercise protocols on Asprosin and Brain-Derived Neurotrophic Factor (BDNF) levels in inactive normal weight and obese individuals. A total of 20 male individuals aged 18–65 years, ten normal weight (NW) (Body Mass Index (BMI): 18.5–24.99 kg/m2) and 10 obese (Ob) (BMI: 24.99–35.00 kg/m2) participated in this study, voluntarily. Moderate aerobic exercise (AE) (main circuit 30 min, between 40 and 59% of Heart Rate Reserve: HRR) and High-Intensity Interval exercise (HIIE) running protocols (main circuit 20 min, between 75 and 90% of the HRR for 1 min*10 times, and 1-min active rest at 30% of the HRR) was applied to the volunteer participants in the morning hours (08.00–10.00 a.m.), following the night fasting (at least 8–10 h) for at least 3 days between each other. Blood samples were collected from the participants before and immediately after each exercise protocol, and serum asprosin and BDNF hormone levels were determined by Enzyme-Linked Immunosorbent Assay” method. Basal serum asprosin was found to be significantly higher in the Ob group compared to the NW group (p < .001), while the basal serum BDNF hormone was found to be lower (p < 0.05). It was observed that the serum asprosin level of both groups decreased significantly after both AE and HIIE protocols (p < 0.05). In addition, there was a significantly higher decrease in serum asprosin level in the Ob group compared to the NW group after HIIE protocol. For the Ob group, serum BDNF level increased considerably after HIIE protocol compared to AE protocol (p < 0.05). Serum asprosin was found to be higher in the Ob group, while the serum BDNF was found to be lower. In addition, the acute exercises of different intensity significantly affected hormones that regulate appetite metabolism. In particular, it was observed that the HIIE protocol had a greater effect on the regulation of appetite (hunger-satiety) in the Ob group. This result can be taken into account when planning training programs for these individuals.

Impact of 3 months of detraining after high intensity exercise on menopause-related symptoms in early postmenopausal women - results of the randomized controlled actlife project.

ClinicalTrials.gov: NCT03959995.

High intensity exercise performance and muscle damage. A role for free radicals

The purpose of this paper is to outline muscle damage and oxidative stress responses to high intensity exercise protocols. The information provided will be important for athletes, coaches, and the general population to provide information related to mechanisms and consequences of high intensity exercise performance

Recommending exercise to boost mental sharpness in your aging patients? What clinicians need to know to prescribe right, measure better, and increase buy‐in

AbstractBackgroundAs our population ages, many individuals are at risk of developing age‐related cognitive decline. A wealth of scientific evidence supports that being physically active may prevent or delay the onset of cognitive impairment and dementia and related functional impairments. However, key barriers remain: 1) optimal exercise parameters for cognitive brain health have not been fully elucidated; 2) while most clinicians recommend physical activity, and older adults recognize its health benefits, the overwhelming majority of older adults fail to regularly participate in regular physical activity. Key preliminary results from two studies will be presented and discussed.MethodFifty‐one sedentary aging participants at risk for cognitive decline (age 62.9±6.8, 76.9% female) participated in Study 1. All participants completed an eight‐week moderate to high intensity exercise protocol and underwent assessments of neurocognitive and cardiorespiratory performance. In Study 2, a separate sample of fifteen individuals (68.1±6.5 years, 76.8% female) participated in a focus group to discuss factors influencing their exercise engagement.ResultStudy 1: All participants combined demonstrated significant improvements in cognition (measured by the Repeatable Battery for the Assessment of Neuropsychological Status [RBANS]) and cardiorespiratory fitness assessed by pre‐to‐post improvements in heart rate recovery (HRR) after eight weeks of exercise (p&lt;0.05). Additionally, multiple regressions revealed a relationship between cognition (RBANS list learning [ß = .22] and RBANS list recognition [ß = 1.86] and fitness (p&lt;0.05). Study 2: The focus group revealed that participants felt providers’ physical activity recommendations were too general, and did not consider their physical and contextual limitations, leading them to feel less likely to follow through with them.ConclusionOur data suggests that committing to a regular exercise regimen, even for a brief two‐month period, can promote improvements in cardiorespiratory fitness and cognition. We discuss the potential utility of heart rate recovery, an easy clinical measure that takes just a few minutes, to estimate cardiorespiratory fitness that appears to be relevant for exercise‐induced improvements in cognition. We discuss simple strategies to effectively translate current guidelines into the needs of the individual, considering the challenges and demands of the clinical setting.

Acute physiological responses to high-intensity interval exercise in patients with coronary artery disease.

Time spent closer to maximal effort during exercise is a potent stimulus for cardiorespiratory adaptations. The primary purpose was to determine which high-intensity interval exercise (HIIE) protocol provided the greatest physiological stimulus by comparing time spent ≥ 90% peak oxygen consumption (V̇O2peak) and heart rate reserve (HRR) in patients with coronary artery disease (CAD) in response to 3 HIIE protocols and the exercise standard of care, moderate-intensity continuous exercise (MICE). A secondary purpose was to assess protocol preference. Fifteen patients with CAD (6 females, 67 ± 6years) underwent measurements of V̇O2 and heart rate during MICE and three HIIE protocols all performed on a treadmill. The HIIE protocols included one with long intervals (4 × 4-min), short intervals (10 × 1-min), and an adapted version of the 4 × 4 [Toronto Rehabilitation Institute Protocol, (TRIP)]. Time spent ≥ 90% V̇O2peak and HRR were compared. Time spent ≥ 90% V̇O2peak was higher during 4 × 4 (6.3 ± 8.4min) vs. MICE (1.7 ± 3.9min; P = 0.001), while time spent ≥ 90% HRR was higher during 4 × 4 (6.0 ± 5.3min) vs. MICE (0.1 ± 0.2min; P < 0.001) and 10 × 1 (0.7 ± 0.8min; P = 0.016). TRIP had similar responses as 10 × 1 and MICE. The 10 × 1 was the most preferred protocol and the 4 × 4 was the least preferred protocol. Longer intervals (4 × 4) provided the greatest physiological stimulus compared to the exercise standard of care and shorter intervals. However, this protocol was least preferred which may impact exercise adherence. Although the physiological stimulus is important to maximize training adaptations, exercise preferences and attitudes should be considered.

Abstract 13181: Accurate, Non-Invasive Monitoring of VO2 Max Using Wearable ECG Technology

Introduction: Maximal aerobic capacity (VO2 max) corresponds to the maximum volume of oxygen the body can utilize during high-intensity exercise and is widely regarded as the criterion measurement for cardiorespiratory fitness (CRF). In addition to its use as a metric to evaluate aerobic endurance, VO2 max has been identified as a significant and independent risk factor for all-cause and disease-specific mortality. The integration of VO2 max functionality into wearable devices allows CRF to be unobtrusively monitored, providing an important insight into clinical health. Methods: ECG data acquired on the non-invasive HeartKey ® Chest Module throughout a multi-stage, high-intensity exercise protocol was used by the HeartKey VO2 Max algorithm to generate a VO2 max rate. The algorithm’s performance was evaluated against data simultaneously collected on gold standard CRF equipment using indirect calorimetry (Korr ® CardioCoach). Participants (N=45) of varying ages and physical fitness were recruited to ensure a wide range of CRF levels were represented. Results: A strong correlational relationship ( R= 0.9) was observed between the HeartKey VO2 max values and those generated on the criterion device. HeartKey VO2 Max algorithm demonstrated high accuracy, with a mean absolute percentage error of ~6% over the 45 subjects. The mean absolute error for the HeartKey algorithm was 3.1 ml/min/kg, with a root mean square error value of 3.9 ml/min/kg. Conclusions: HeartKey generated highly accurate and reliable VO2 max metrics from ECG data collected on a non-obstructive, non-invasive, dry electrode wearable device, with a performance comparable to that of a gold standard indirect calorimetry device. This study highlights the opportunity to make CRF monitoring accessible in everyday scenarios by using wearable ECG devices functionalized with accurate VO2 max capability, which is convenient, cost-effective, and highly scalable.

Effect of high-intensity interval exercise on renal artery hemodynamics in healthy young adults.

High-intensity interval exercise is useful for sustained exercise; however, its effect on renal artery hemodynamics is unclear. This study aimed to evaluate changes in renal artery blood flow velocity due to high-intensity interval exercise. Ten healthy adults (age, 23.5±1.2 years) completed high-intensity interval exercise and moderate-intensity continuous exercise protocols on separate days. The high-intensity interval exercise protocol (total duration, 26 min) comprised eight sets of high-intensity exercise sessions at 85% maximum oxygen uptake for 1 min, with intervals of 40% maximum oxygen uptake for 2 min between sets. The moderate-intensity continuous exercise protocol comprised 40 min of exercise at 40% maximum oxygen uptake. Renal artery blood flow velocity and natural log-transformed high frequency spectral power (an index of cardiac parasympathetic nervous system activity) were measured before and after exercise. Additionally, exercise enjoyment was measured using a questionnaire. Renal artery blood flow velocity did not significantly differ between protocols or timepoints for either protocol. However, the natural log-transformed high frequency spectral power was significantly lower with high-intensity interval exercise than with moderate-intensity continuous exercise (P<0.001, F=25.97) during exercise and at 10 min after exercise, and it did not return to pre-exercise levels with high-intensity interval exercise. Moreover, there was no significant difference in exercise enjoyment between the two protocols. In healthy young adults, high-intensity interval exercise reduces parasympathetic activity; however, it does not produce any significant changes in renal artery hemodynamics after exercise.

Acute Floatation-REST Improves Perceived Recovery After a High-Intensity Resistance Exercise Stress in Trained Men.

The aim of the present investigation was to determine whether a 1-h floatation-restricted environmental stimulation therapy (floatation-REST) session could augment recovery from high-intensity resistance exercise (6 × 10 back squats, 2-min rest) known to induce significant metabolic, adrenergic, and mechanical stress. Eleven healthy resistance-trained males (age, 22.5 ± 2.3 yr; height, 176.4 ± 6.0 cm; weight, 85.7 ± 6.2 kg; back squat one-repetition maximum, 153.1 ± 20.1 kg; strength-to-weight ratio, 1.8 ± 0.2) completed the within-subject, crossover controlled study design. Participants completed two exercise testing blocks separated by a 2-wk washout. In one block, the high-intensity resistance exercise protocol was followed by a 1-h floatation-REST session, whereas recovery in the alternate block consisted of a passive sensory-stimulating control. Markers of metabolic stress, neuroendocrine signaling, structural damage, inflammation, and perceptions of soreness, mood state, and fatigue were assessed over a 48-h recovery window. Floatation-REST significantly attenuated muscle soreness across recovery ( P = 0.035) with greatest treatment difference immediately after the intervention ( P = 0.002, effect size (ES) = 1.3). Significant differences in norepinephrine ( P = 0.028, ES = 0.81) and testosterone ( P = 0.028, ES = 0.81) immediately after treatment revealed the modification of neuroendocrine signaling pathways, which were accompanied by greater improvements in mood disturbance ( P = 0.029, ES = 0.81) and fatigue ( P = 0.001, ES = 1.04). Because no adverse effects and significant and meaningful benefits were observed, floatation-REST may prove a valuable intervention for managing soreness and enhancing performance readiness after exercise.

Attenuated Metabolic and Cardiorespiratory Responses to Isoenergetic High-Intensity Interval Exercise of Short Versus Long Bouts.

To compare the metabolic, cardiorespiratory and perceptual responses to three isoenergetic high-intensity interval exercise (HIIE) protocols of different bout duration and an isoenergetic continuous exercise protocol. Eleven healthy males (age, 28 ± 6 yr) performed four 20-min cycling trials of equal mean power output 1 wk apart. Participants cycled either continuously (CON) or intermittently with 10 s (HIIE10), 30 s (HIIE30), or 60 s (HIIE60) bouts at intensities corresponding to 49% (CON) or 100% of power at peak oxygen uptake (V̇O2peak). Recovery intervals during the HIIE trials were 15, 45, and 90 s, respectively. Average V̇O2 was similar in the HIIE trials (2.29 ± 0.42, 2.20 ± 0.43, and 2.12 ± 0.45 L·min-1, for HIIE10, HIIE30, and HIIE60, respectively), whereas in CON (2.02 ± 0.38 L·min-1), it was lower than HIIE10 (P = 0.002) and HIIE30 (P = 0.043). Average pulmonary ventilation (VE) was higher in HIIE60 compared with HIIE10, HIIE30, and CON (75.8 ± 21.8 L·min-1 vs 64.1 ± 14.5 L·min-1, 64.1 ± 16.2 L·min-1, and 54.0 ± 12.5 L·min-1, respectively, P < 0.001). The peak values and oscillations of V̇O2 and VE in HIIE60 were higher compared with all other trials (P < 0.001). Blood lactate concentration was higher in HIIE60 compared with HIIE10, HIIE30, and CON from the fifth minute onward, reaching 12.5 ± 3.5, 7.2 ± 2.1, 7.9 ± 2.9, and 4.9 ± 1.6 mmol·L-1, respectively, at the end of exercise (P < 0.001). RPE was higher and affective responses were lower in HIIE60 compared with all other trials toward the end of exercise (P < 0.001). These findings highlight the importance of bout duration in HIIE, since shorter bouts resulted in attenuated metabolic and cardiorespiratory responses, lower RPE and feelings of displeasure compared with a longer bout, despite equal total work, duration, and work-to-recovery ratio. These results may have implications for the prescription of HIIE in various populations.

HIIE Protocols Promote Better Acute Effects on Blood Glucose and Pressure Control in People with Type 2 Diabetes than Continuous Exercise.

This study compared the acute effects of a session of different high-intensity interval exercise (HIIE) protocols and a session of moderate-intensity continuous exercise (MICE) on blood glucose, blood pressure (BP), and heart rate (HR) in people with Type 2 Diabetes Mellitus (DM2). The trial included 44 participants (age: 55.91 ± 1.25 years; BMI: 28.95 ± 0.67 kg/m2; Hb1Ac: 9.1 ± 2.3%; 76 mmol/mol) randomized into three exercise protocols based on the velocity at which maximum oxygen consumption was obtained (vVO2 max): long HIIE (2 min at 100% vV̇o2peak + 2 min of passive rest); short HIIE (30 s at 100% vV̇o2peak + 30 s of passive rest); or MICE (14 min at 70% vV̇o2peak) on a treadmill. Capillary blood glucose, BP, and HR measurements were taken at rest, during peak exercise, immediately after the end of exercise, and 10 min after exercise. Long and short HIIE protocols reduced capillary blood glucose by 32.14 mg/dL and 31.40 mg/dL, respectively, and reduced systolic BP by 12.43 mmHg and 8.73 mmHg, respectively. No significant changes were observed for MICE. HIIE was found to promote more acute effects than MICE on glycemia and BP in people with DM2.

Effects of curtailed sleep on cardiac stress biomarkers following high-intensity exercise

ObjectivePhysical exercise—especially at high intensity—is known to impose cardiac stress, as mirrored by, e.g., increased blood levels of cardiac stress biomarkers such as cardiac Troponin T (cTnT) and NT-proBNP. We examined healthy young participants to determine whether a few nights of short sleep duration alter the effects of acute exercise on these blood biomarkers. MethodsSixteen men participated in a randomized order in a crossover design, comprising three consecutive nights of a) normal sleep duration (NS, 8.5 h of sleep/night) and b) sleep restriction (SR, 4.25 h of sleep/night). Blood was repeatedly sampled for determination of NT-proBNP and cTnT serum levels before and after a high-intensity exercise protocol (i.e., 75% VO2maxReserve cycling on an ergometer). ResultsUnder pre-exercise sedentary conditions, blood levels of cTnT and NT-proBNP did not significantly differ between the sleep conditions (P > 0.10). However, in response to exercise, the surge of circulating cTnT was significantly greater following SR than NS (+37–38% at 120–240 min post-exercise, P ≤ 0.05). While blood levels of NT-proBNP rose significantly in response to exercise, they did not differ between the sleep conditions. ConclusionRecurrent sleep restriction may increase the cardiac stress response to acute high-intensity exercise in healthy young individuals. However, our findings must be further confirmed in women, older subjects and in patients with a history of heart disease.

Acute Physiological Responses to Moderate-Intensity Continuous, High-Intensity Interval, and Variable-Intensity Intermittent Exercise

ABSTRACT Purpose: This study examined acute physiological responses to moderate-intensity continuous exercise (MICE), variable-intensity intermittent exercise (VIIE), and high-intensity interval exercise (HIIE) protocol, matched for total work output in healthy adults (n = 8, age = 25.1 ± 6.0 yrs). Methods: Three experimental trials were completed in a random order. MICE was continuous exercise at 40% of peak work rate (WRpeak). VIIE consisted of sixteen 10-sec bursts at 120% WRpeak, sixteen 20-sec bursts at 60% WRpeak and recovery at 20% WRpeak interspersed throughout the protocol. HIIE consisted of eight intervals of 2 minutes at 70% WRpeak and 1 minute at 20% WRpeak. Oxygen consumption during work-intervals and time within moderate and vigorous-intensity zones determined the magnitude and duration of physiological stresses. Perceptual responses were measured by affective response and post-exercise enjoyment (PACES). Repeated-measure ANOVAs analyzed differences between trials. Statistical significance was established if p ≤ 0.05. Results: Oxygen consumption during work-intervals in VIIE was greater than MICE, but less than HIIE. VIIE and HIIE had similar duration within vigorous-intensity zone (11.1 ± 3.5 min vs. 13.5 ± 1.3 min); both were greater than MICE (4.9 ± 1.1 min). The time spent in the moderate-intensity zone was different between all trials (VIIE = 11.1 ± 2.0 min; MICE = 17.4 ± 5.2 min; HIIE = 4.9 ± 0.4 min). Affective responses were similar among all trials. Post-exercise enjoyment was greater in VIIE than HIIE; both were not different from MICE. Conclusion: These results suggests the VIIE paradigm could be a viable alternative to HIIE and MICE protocols.

Neuromuscular impairment after high-intensity running and vertical jump exercise protocols

BACKGROUND: Repetitive stretch-shortening cycle exercises generate high rates of mechanical work and consequently induce substantial muscular fatigue related to delayed neuromuscular functions. OBJECTIVE: To investigate the neuromuscular impairment after high-intensity exercise protocols involving different gravity loads in stretch-shortening cycle – running (RUN) and vertical jumps (VJ). METHODS: Twenty-two healthy men, divided into two groups, VJ and RUN participated in this study. The individuals performed a training session involving six bouts of 30 s of VJ or RUN. The isokinetic PM (PM) of the knee extensors and flexor muscles, rate of perceived exertion and delayed onset muscle soreness (DOMS) were evaluated at pre, post, 24 h and 48 h post-training. RESULTS: The concentric and eccentric PM of the extensor in the RUN group was reduced until 24 h, while in the VJ a decrement was observed until 48 h. Following running, the PM of the flexors decreased until 48 h, while for VJ there was an eccentric PM decrement at 48 h. The DOMS increased at the anterior thigh and only after VJ training for 48 h. CONCLUSION: Acute and delayed neuromuscular impairment may be observed after both exercise regimens, but high-intensity training using vertical jumps seems to induce a more pronounced impairment than running.

High Intensity Physical Exercise before the Brain Ischemia Promotes Increase in Brain Injury

Studies have demonstrated the beneficial effects of light- and moderate-intensity physical exercise on the nervous system of animals with cerebral ischemia. To investigate the effects of two high-intensity physical exercise protocols, standardized for resistance and strength gain, in rats trained before cerebral ischemia induced by Bilateral Common Carotid Artery Occlusion (BCCAO). Forty-eight male Wistar rats were divided into two groups: with ischemia and without ischemia (sham). Both groups were subdivided into animals that performed high-intensity exercises in the muscle strength modality (I+Ex2; Sham+Ex2; n=16); animals submitted to high-intensity exercises in the aerobic modality (I+Ex1; Sham+Ex1; n=16), and animals that did not practice physical exercises - sedentary (I+Sed; Sham+Sed, n=16). Cerebral ischemia was induced using the BCCAO model. The physical training program used before the procedure was of high intensity, in the aerobic and muscular strength modalities, and was performed using a vertical ladder, for 4 weeks, 5 days per week. In order to process and stain the brain tissue, the Nissl method was used for neuron labeling and quantification in the cortex, striatum, and hippocampus. As for the animals’ body weight and the heart weight differences were found between the groups I+Ex2 and Sham+Ex2 (p<0.05). Data on neuron quantification in the cerebral cortex, dentate gyrus, and right and left striatum revealed significant differences between groups. High-intensity physical training in the strength gain modality promotes significant damage to the animal's brain when performed prior to BCCAO-induced cerebral ischemia.

Energy matching of a high-intensity exercise protocol with a low-intensity exercise protocol in young people

© 2021 Springer Nature Switzerland AG. This is the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1007/s11332-021-00774-3