Acute High-intensity Interval Research Articles

An acute bout of 4 × 4-min or 10 × 1-min HIIT improves β cell glucose sensitivity in postmenopausal females with type 2 diabetes: a secondary analysis.

Improvements in glycemic control following acute exercise are typically attributed to improved postexercise insulin sensitivity (IS) with comparatively little known about how acute exercise impacts β cell function, especially in postmenopausal females. We determined how two high-intensity interval training (HIIT) protocols, matched for total estimated energy expenditure, impact β cell function in postmenopausal females with type 2 diabetes. Thirteen postmenopausal females (70 ± 5 yr; 12 ± 7 yr since diagnosis, 80.9 ± 13.8 kg, 32.4 ± 5.6 kg·m2; HbA1c-49.8 ± 10.3 mmol/mol [6.7 ± 1.0]) living with type 2 diabetes were included in this semirandomized crossover trial. The trial involved an initial resting control condition followed by two HIIT conditions [4 × 4-min HIIT (HIIT4) and 10 × 1-min HIIT (HIIT10)] completed in a randomized order 2-4 days apart. β cell function (glucose sensitivity) and insulin sensitivity were determined from a 2-h mixed-meal tolerance test performed 2 h after rest or HIIT. Both HIIT4 and HIIT10 significantly improved β cell glucose sensitivity compared with control (15 pmol/min/m2/[mmol/L], [95% confidence interval (CI) 6, 23]; P = 0.002 and 16 pmol/min/m2/[mmol/L], [95% CI 7, 25]; P = 0.002, respectively), with no difference between HIIT protocols (1 [-8, 10], P = 0.79). There were no significant differences in IS metrics (Matsuda index, OGIS, Stumvoli, and QUICKI) between the conditions. An acute bout of 4 × 4-min or 10 × 1-min HIIT improves β cell glucose sensitivity in postmenopausal females living with type 2 diabetes. ClinicalTrials.gov: NCT04986345.NEW & NOTEWORTHY This is the first study to explore the effects of acute high-intensity interval training (HIIT) on β cell function in postmenopausal women with type 2 diabetes. Our crossover trial compares two HIIT protocols, matched for total estimated energy expenditure, examining their impacts on β cell function and insulin sensitivity. Despite the absence of an insulin-sensitizing effect, we show robust effects of HIIT on β-cell function, including an improvement in β-cell glucose sensitivity.

A085: Effects of High-Intensity Interval Training Combined with Meditation on Cognitive Function in Sedentary College Students

Background/Purpose: Prolonged sedentary behavior is prevalent in the daily lives of Chinese college students. Given that college students, as representatives of the younger demographic, confront increased academic, social, and other challenges, it is imperative to explore strategies for enhancing their cognitive function. The principal aim of this investigation was to assess the impact of acute high-intensity interval training combined with meditation on the cognitive function of sedentary college students. Methods: A total of 51 sedentary college students (20.24±2.19) were included in this study. The subjects were randomly divided into high-intensity interval training combined with meditation group, high-intensity interval training group, and control group. Stroop task was used to record the accuracy and reaction times, and a near-infrared spectral brain imaging system was used to monitor the brain's oxy-hemoglobin concentration responses. Results: (1) Stroop task reaction times exhibited a significant main effect for the test phase (F=30.142, p < 0.001, η2=0.386) and a significant interaction between test phase and group (F=7.627, p = 0.001, η2=0.241). Simple effect analysis revealed faster post-test reaction times for both the Combination (F=7.783, p = 0.008, η2=0.140) and HIIT group (F=37.231, p < 0.001, η2=0.437) compared to pre-test. (2) The fNIRS data showed that the activation of channel 7 (F=12.527, p = 0.001, η2=0.207), channel 15 (F=13.742, p = 0.001, η2=0.223) and channel 16 (F=10.529, p = 0.002, η2=0.180) in the acute high-intensity training group was significantly higher than that in the pre-test, and the activation of channel 15 (F=14.832, p < 0.001, η2=0.236) and channel 16 (F=8.605, p = 0.005, η2=0.152) in the combined group was higher than that in the pre-test. Conclusion: Both acute high-intensity interval training combined with meditation and acute high-intensity interval training independently exhibited positive effects on cognitive performance in sedentary college students. Additionally, the combined intervention significantly enhanced the activation levels of factor L-DLPFC, while acute high-intensity interval training significantly increased the activation levels of both factors L-DLPFC and R-FPA. This study found a new intervention method to improve the cognitive performance of sedentary college students.

Long-Term High-Intensity Interval Training Intervention Improves Emotional Conflict Control in Association With Right Ventrolateral Prefrontal Activation in Males With Methamphetamine Use Disorder: A Randomized Controlled Trial.

Acute high-intensity interval training (HIIT) has cognitive benefits in individuals with methamphetamine use disorder (MUD), yet it remains largely unknown the benefits of long-term HIIT on emotional conflict control and its neural mechanism in individuals with MUD. The current study conducted a 36-week low-volume HIIT intervention to investigate the effects of HIIT on emotional conflict control in males with MUD and their prefrontal cortex (PFC) activation. This study was a sub-study of the Study for Rehabilitation Training Model Construction and Training Effect of High Intensity Compound Exercise Prescription. Forty males with MUD (31.50 ± 4.33 years) were randomly assigned to the HIIT group and control group. The HIIT group received a 36-week low-volume HIIT intervention, while the control group maintained daily physical exercise. The emotional conflict task (emotional face-word Stroop task) with functional near-infrared spectroscopy (fNIRS) recording and subjective craving test were performed before and after the intervention. The results showed that the HIIT intervention reduced the emotional conflict and increased cortical activations of right dorsolateral PFC (dlPFC) and right ventrolateral PFC (vlPFC). More importantly, the HIIT-induced decreased emotional conflict was associated significantly with increased right vlPFC activation. In addition, subjective craving was also reduced after HIIT intervention. While the control group showed significant changes in neither brain activation nor the craving. These findings suggest that long-term low-volume HIIT can improve PFC activation, promote emotional conflict control, and reduce subjective craving in males with MUD. HIIT seems to be an effective method of withdrawal rehabilitation for males with MUD.

Effects of acute rope skipping exercises of different exercise modes on cognitive function in 9–10-year-old children

To explore the effects of acute high-intensity interval rope skipping exercise and acute moderate-intensity continuous rope skipping exercise on cognitive function in 9–10-year-old children, this study aims to inform the selection of appropriate jump rope methods for cognitive training in physical activities. A total of 60 students from two classes of fourth grade in a primary school were selected as research subjects. After matching according to gender, they were randomly divided into HIIT group, MICT group and control group. The Digit Span Test (DST), Attention Network Test (ANT) and Stroop Color Word Test were conducted three days before the intervention and 5 min after the intervention. During the intervention, the HIIT group performed a high-intensity intermittent rope skipping exercise (required fast jumping with feet together, practice for 1 min and rest for 1 min, jump continuously for 5 groups, and the exercise intensity is ≥ 85% of the maximum heart rate), while the MICT group performed a moderate-intensity continuous rope skipping exercise (required to medium jumping with feet together, jump continuously for 5 min, and the exercise intensity is 60–80% of the maximum heart rate), and the control group rests in place. After the intervention, both HIIT and MICT groups showed increased DST total scores, improved executive control network efficiency, and faster inhibitory control response speeds, with no significant changes in accuracy. The HIIT group also exhibited increased orienting network efficiency and no significant changes in accuracy. Acute rope skipping exercises using HIIT and MICT methods can improve the working memory, executive control network efficiency and inhibitory control ability of children aged 9–10 years old. Additionally, conducting acute rope skipping exercises using HIIT method can also enhance their orienting network efficiency.

Impact of exercise and fasting on mitochondrial regulators in human muscle.

To investigate the impact of acute energetic stress (acute HIIE and fasting) on ERRγ, PPARβ, NR1D1, NR4A1, and TFEB in human skeletal muscle. The current study performed secondary analyses using muscle biopsy samples from two previously published studies: study 1) leg muscle biopsies from nine men and eight women were obtained pre and 3 h following acute high-intensity interval cycling exercise (HIIE); study 2) leg muscle biopsies were obtained from nine men pre-, during, and post-an 8 h fast with or without 2 h of arm ergometer exercise. RT-PCR was performed on samples from each study to determine the mRNA expression of ERRγ, PPARβ, NR1D1, NR4A1, and TFEB. Additionally, we retrieved data from meta-analyzed human muscle gene expression using the publicly available database MetaMex. PGC-1α (p<0.01, d=1.98) and NR4A1 (p<0.01, d=1.36) mRNA expression significantly increased while TFEB (p≤0.05, d=0.70) decreased following HIIE. Significant decreases in NR4A1 and NR1D1 mRNA expression were observed following an 8 h fast. Our MetaMex analyses revealed significant increases (p<0.05) in PGC-1α andNR4A1 expression following aerobic and resistance exercise, and in PPARβ expression following resistance exercise. Our data indicate that acute HIIE stimulates increases in NR4A1 and PGC-1α and decreases in TFEB mRNA expression in human skeletal muscle. Additionally, a short term (8 h) fast reduced the mRNA expression of the transcriptional regulators NR4A1 and NR1D1- potentially as a mechanism ofdecreasing mitochondrial biogenesis to reduce energy expenditure during a period of restricted energy availability.

Impact of Acute High-intensity Interval Training on Cortical Excitability, M1-related Cognitive Functions, and Myokines: A Randomized Crossover Study

High-intensity interval training (HIIT) is a time-efficient, safe, and feasible exercise type that can be utilized across different ages and health status. This randomized cross-over study aimed to investigate the effect of acute HIIT on cortical excitability, M1-related cognitive functions, cognition-related myokines, brain-derived neurotrophic factor (BDNF), and Cathepsin B (CTSB). Twenty-three sedentary young adults (mean age: 22.78 years ± 2.87; 14 female) participated in a cross-over design involving two sessions: either 23 min of HIIT or seated rest. Before and after the sessions, cortical excitability was measured using transcranial magnetic stimulation, and M1-related cognitive functions were assessed by the n-back test and mental rotation test. Serum levels of BDNF and CTSB were assessed using the ELISA method before and after the HIIT intervention. We demonstrated that HIIT improved mental rotation and working memory, and increased serum levels of BDNF and CTSB, whereas cortical excitability did not change. Our findings provide evidence that one session of HIIT is effective on M1-related cognitive functions and cognition-related myokines. Future research is warranted to determine whether such findings are transferable to different populations, such as cognitively at-risk children, adults, and older adults, and to prescribe effective exercise programs.

Arterial stiffness and wave reflection responses to acute and chronic high intensity interval training in healthy older adults

Aging leads to large elastic artery stiffness which is associated with early return of wave reflection. These age-related alterations increase left ventricular afterload, predisposing older adults to cardiovascular disease. Endurance training is an effective strategy to reduce cardiovascular disease risk. We have developed a supervised home-based exercise intervention using high intensity interval training on an all-extremity non-weight-bearing ergometer (HIIT-ANE). This study aimed to test the following hypotheses in healthy older adults: 1) arterial stiffness and wave reflection would decrease in response to chronic HIIT-ANE, 2) arterial stiffness and wave reflection responses to acute HIIT-ANE would differ in the untrained compared to the trained states, and 3) arterial stiffness and aortic wave reflection responses to acute and chronic HIIT-ANE would be related. Twenty older adults (66±1 years, mean ± SE; 11 postmenopausal women and 9 men) participated in this study. Carotid-femoral pulse wave velocity (cfPWV) and augmentation index at heart rate 75 bpm (AIx@75)—indices of arterial stiffness and wave reflection, respectively—were assessed by SphygmoCor XCEL at baseline (T0), following 8 weeks of normal lifestyle (T1; control condition), and following 8 weeks of supervised home-based HIIT-ANE (T2). Acute cfPWV and AIx@75 responses to HIIT-ANE were assessed at pre-, end-of-, 1-hr post- and 24-hrs post-exercise, in the untrained and trained states. cfPWV increased after 8 weeks of normal lifestyle (T0 vs. T1: 7.9±0.3 vs. 8.2±0.3 m/s, P=0.03), but it decreased following 8 weeks of HIIT-ANE (T1 vs. T2: 8.2±0.3 vs. 7.7±0.3 m/s, P&lt;0.001). AIx@75 decreased after 8 weeks of HIIT-ANE compared to baseline and following 8 weeks of normal lifestyle (T0 vs. T2: 23.7±1.8 vs. 17.8±1.9 %, P&lt;0.001; T1 vs. T2: 24.9±2.2 vs. 17.8±1.9 %, P&lt;0.001). Acute cfPWV and AIx@75 responses to HIIT-ANE were similar in the untrained and trained states ( P for condition×time interaction; cfPWV: P=0.8; AIx@75: P=0.9). cfPWV and AIx@75 responses to chronic HIIT-ANE were not significantly related with acute responses to HIIT-ANE in the untrained (cfPWV: r=0.07, P=0.8; AIx@75: r=-0.32, P=0.2) and trained states (cfPWV: r=0.10, P=0.7; AIx@75: r=-0.32, P=0.2). In conclusion, we have demonstrated that supervised home-based HIIT-ANE has beneficial vascular effects in healthy older adults. We also showed that acute vascular responses to HIIT-ANE do not change from the untrained to trained state and are not predictive of chronic vascular responses to HIIT-ANE. This work was supported by the National Institute of Aging grant AG063143. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of acute high-intensity interval exercise on a mouse model of doxorubicin-induced cardiotoxicity: a pilot study

BackgroundIt is unknown whether high-intensity interval exercise (HIIE) may potentiate or attenuate the cardiotoxic effect of chemotherapy agents such as doxorubicin (DOX) when performed shortly after treatment. The study aimed to investigate the effect of acute HIIE on cardiac function and structure performed either 1, 2 or 3 days after DOX injection in an animal model.MethodsFemale C57bl/6 mice (n = 28), 70 days old, received a bolus 20 mg/kg intravenous tail vein DOX injection. Three exercise groups performed 1 HIIE session (16 sets of 1 min at 85–90% of peak running speed) at 1 (n = 7), 2 (n = 7), and 3 days (n = 8) following the DOX injection. A sedentary (SED) group of mice (n = 6) did not exercise. Animals underwent echocardiography under light anesthesia (isoflurane 0.5-1%) before and 7 days after the DOX injection. Animals were sacrificed on day 9 and hearts were collected for morphometric and histological analysis.ResultsAnimals exercising on day 3 had the smallest pre-post reduction in left ventricular fractional shortening (LVFS) (MΔ= -1.7 ± 3.3; p = 0.406) and the SED group had the largest reduction (MΔ=-6.8 ± 7.5; p = 0.009). After reclassification of animals according to their exercise compliance (performing > 8/16 of high-intensity bouts), LVFS in compliant mice was unchanged over time (LVFS MΔ= -1.3 ± 5.6; p = 0.396) while non-compliant animals had a LVFS reduction similar to sedentary animals. There were no significant differences in myocardial histology between groups.ConclusionsIn this pilot murine study, one single HIIE session did not exacerbate acute doxorubicin-induced cardiotoxicity. The timing of the HIIE session following DOX injection and the level of compliance to exercise could influence the negative impact of DOX on cardiac function.

Effects of acute and chronic high-intensity interval training on serum irisin, BDNF and apelin levels in male soccer referees

This study was aimed to investigate the effects of acute and chronic High Intensity Interval Training (HIIT) on Irisin, BDNF (brain-derived neurotrophic factor), and Apelin levels. The study included twenty-one male soccer referees. Blood from the participants was collected at the beginning of study (1. first measurement: baseline value). HIIT was conducted and blood was immediately collected (2. second measurement: acute effect). Next, HIIT was carried out for 20 minutes of 4 days a week in bouts of running (75 meters in 20 seconds) and walking (25 meters in 20 seconds). Blood was collected at the end of 12 weeks (3. third measurement: chronic effect). HIIT was performed and blood was again collected (4. fourth measurement: acute effect after the chronic effect). There was a gradual increase in irisin, BDNF, and apelin levels (p &lt; 0.001). The increase for irisin was 2% in the second measurement, 106% in the third, and 111% in the fourth compared to the first measurement. The increase for BDNF was 39% in the second measurement, 116% in the third, and 133% in the fourth. Apelin levels were increased by 11%, 19%and 28%, respectively. These results demonstrated that irisin and BDNF might increase only in response to chronic HIIT (4 times a week) while apelin levels might change with both acute and chronic HIIT in healthy trained referees.

Acute High-Intensity Interval Training Improves Esport Performance in Super Smash Brothers Ultimate Competitors

Acute exercise has been shown to improve scores on tests of cognitive function. The cognitive variables that improve with acute exercise are also associated with esport performance. This randomized control trial examined whether performing a high-intensity interval training (HIIT) exercise bout prior to esport competitions produced improvement in Super Smash Brothers Ultimate performance compared with the control group of college-aged e-athletes who did not perform a precompetition HIIT session (n = 28). Both competitions consisted of a round-robin style of play wherein all players in each group faced each other in head-on sets. Competition results after sedentary and after HIIT exercise were compared. Logistic regression indicated that HIIT increased the probability of winning a Super Smash Brothers Ultimate set by approximately twofold (p = .006). These data suggest that HIIT acutely improves esport performance.

Post-acute exercise cardiovagal modulation in older male adults with and without type 2 diabetes

PurposeWe examined heart rate variability (HRV) and baroreflex sensitivity (BRS) disease- and age-related response at 10-and 60-min after an acute high-intensity interval (HIIE) and moderate continuous exercise (MICE) in older adults with and without type 2 diabetes mellitus (T2DM) and healthy young adults.MethodsTwelve older male adults with (57–84 years) and without T2DM (57–76 years) and 12 healthy young male adults (20–40 years) completed an isocaloric acute bout of HIIE, MICE, and a non-exercise condition in a randomized order. Time and Wavelets-derived frequency domain indices of HRV and BRS were obtained in a supine position and offline over 2-min time-bins using Matlab.ResultsHIIE but not MICE reduced natural logarithm root mean square of successive differences (Ln-RMSSD) (d = − 0.85; 95% CI − 1.15 to − 0.55 ms, p < 0.001), Ln-high-frequency power (d = − 1.60; 95% CI − 2.24 to − 0.97 ms2; p < 0.001), and BRS (d = − 6.32; 95% CI − 9.35 to − 3.29 ms/mmHg, p < 0.001) in adults without T2DM (averaged over young and older adults without T2DM), returning to baseline 60 min into recovery. These indices remained unchanged in older adults with T2DM after HIIE and MICE. Older adults with T2DM had lower resting Ln-RMSSD and BRS than aged-matched controls (Ln-RMSSD, d = − 0.71, 95% CI − 1.16 to − 0.262 ms, p = 0.001; BRS d = − 3.83 ms/mmHg), 95% CI − 6.90 to − 0.76, p = 0.01).ConclusionsCardiovagal modulation following acute aerobic exercise is intensity-dependent only in adults without T2DM, and appears age-independent. These findings provide evidence of cardiac autonomic impairments in older adults with T2DM at rest and following aerobic exercise.

Acute high-intensity interval exercise improves food-related cognition in young adults with obesity: An ERP study

Purpose Cognitive function, particularly food-related cognition, is critical for maintaining a healthy weight and preventing the acceleration of obesity. High-Intensity Interval Exercise (HIIE) is an increasingly popular form of exercise and has been shown to improve physical fitness and cognitive function. However, there is limited research on the effects and underlying mechanisms of HIIE on general and food-related cognition among adults with obesity. The aim of the current study was to examine the influence of a single bout of HIIE on food-related cognition among young adults with obesity.Methods Fifteen young men with obesity (BMI = 33.88 ± 4.22, age = 24.60 ± 5.29 years) were recruited. Participants took part in a HIIE condition consisting of 30 minutes of stationary cycle exercise (5-min warm-up, 20-min HIIE and 5-min cool down), and a control session consisting of a time and attention-matched period of sedentary rest in a counterbalanced order. Behavioral (reaction time and accuracy) and event-related potential measures (P3 and the late positive potential, LPP) elicited during a food-related Flanker task were measured after the HIIE and control session.Results Shorter response times were observed following HIIE, regardless of congruency or picture type, with no change in accuracy. Increased P3 and LPP amplitudes were observed following HIIE relative to the control session.Conclusion The findings suggest a single bout of HIIE has a beneficial effect on general and food-related cognition among young adults with obesity, with increased recruitment of cognitive resources to support cognitive control. Future research is warranted to examine the dose-response relationship between acute bouts or longer participation in HIIE on food-related cognition in obesity.

Muscle miRNAs are influenced by sex at baseline and in response to exercise

BackgroundSex differences in microRNA (miRNA) expression profiles have been found across multiple tissues. Skeletal muscle is one of the most sex-biased tissues of the body. MiRNAs are necessary for development and have regulatory roles in determining skeletal muscle phenotype and have important roles in the response to exercise in muscle. Yet there is limited research into the role and regulation of miRNAs in the skeletal muscle at baseline and in response to exercise, a well-known modulator of miRNA expression. The aim of this study was to investigate the effect of sex on miRNA expression in the skeletal muscle at baseline and after an acute bout of high-intensity interval exercise. A total of 758 miRNAs were measured using Taqman®miRNA arrays in the skeletal muscle of 42 healthy participants from the Gene SMART study (23 males and 19 females of comparable fitness levels and aged 18–45 years), of which 308 were detected. MiRNAs that differed by sex at baseline and whose change in expression following high-intensity interval exercise differed between the sexes were identified using mixed linear models adjusted for BMI and Wpeak. We performed in silico analyses to identify the putative gene targets of the exercise-induced, sex-specific miRNAs and overrepresentation analyses to identify enriched biological pathways. We performed functional assays by overexpressing two sex-biased miRNAs in human primary muscle cells derived from male and female donors to understand their downstream effects on the transcriptome.ResultsAt baseline, 148 miRNAs were differentially expressed in the skeletal muscle between the sexes. Interaction analysis identified 111 miRNAs whose response to an acute bout of high-intensity interval exercise differed between the sexes. Sex-biased miRNA gene targets were enriched for muscle-related processes including proliferation and differentiation of muscle cells and numerous metabolic pathways, suggesting that miRNAs participate in programming sex differences in skeletal muscle function. Overexpression of sex-biased miRNA-30a and miRNA-30c resulted in profound changes in gene expression profiles that were specific to the sex of the cell donor in human primary skeletal muscle cells.ConclusionsWe uncovered sex differences in the expression levels of muscle miRNAs at baseline and in response to acute high-intensity interval exercise. These miRNAs target regulatory pathways essential to skeletal muscle development and metabolism. Our findings highlight that miRNAs play an important role in programming sex differences in the skeletal muscle phenotype.

Physiological and skeletal muscle responses to high-intensity interval exercise in Thoroughbred horses.

The purpose of this study was to determine whether acute high-intensity interval exercise or sprint interval exercise induces greater physiological and skeletal muscle responses compared to moderate-intensity continuous exercise in horses. In a randomized crossover design, eight trained Thoroughbred horses performed three treadmill exercise protocols consisting of moderate-intensity continuous exercise (6 min at 70% VO2max; MICT), high-intensity interval exercise (6 × 30 s at 100% VO2max; HIIT), and sprint interval exercise (6 × 15 s at 120% VO2max; SIT). Arterial blood samples were collected to measure blood gas variables and plasma lactate concentration. Biopsy samples were obtained from the gluteus medius muscle before, immediately after, 4 h, and 24 h after exercise for biochemical analysis, western blotting and real-time RT-PCR. Effects of time and exercise protocol were analyzed using mixed models (p < 0.05). Heart rate and plasma lactate concentration at the end of exercise were higher in HIIT and SIT than those in MICT (heart rate, HIIT vs. MICT, p = 0.0005; SIT vs. MICT, p = 0.0015; lactate, HIIT vs. MICT, p = 0.0014; SIT vs. MICT, p = 0.0003). Arterial O2 saturation and arterial pH in HIIT and SIT were lower compared with MICT (SaO2, HIIT vs. MICT, p = 0.0035; SIT vs. MICT, p = 0.0265; pH, HIIT vs. MICT, p = 0.0011; SIT vs. MICT, p = 0.0023). Muscle glycogen content decreased significantly in HIIT (p = 0.0004) and SIT (p = 0.0016) immediately after exercise, but not in MICT (p = 0.19). Phosphorylation of AMP-activated protein kinase (AMPK) in HIIT showed a significant increase immediately after exercise (p = 0.014), but the increase was not significant in MICT (p = 0.13) and SIT (p = 0.39). At 4 h after exercise, peroxisome proliferator-activated receptor γ co-activator-1α mRNA increased in HIIT (p = 0.0027) and SIT (p = 0.0019) and vascular endothelial growth factor mRNA increased in SIT (p = 0.0002). Despite an equal run distance, HIIT and SIT cause more severe arterial hypoxemia and lactic acidosis compared with MICT. In addition, HIIT activates the AMPK signaling cascade, and HIIT and SIT elevate mitochondrial biogenesis and angiogenesis, whereas MICT did not induce any significant changes to these signaling pathways.

Maternal and Fetal Cardiovascular Responses to Acute High-Intensity Interval and Moderate-Intensity Continuous Training Exercise During Pregnancy: A Randomized Crossover Trial

(Abstracted from Sports Med 2023;53(9):1819–1833) Current recommendations for exercise during pregnancy largely refer to moderate-intensity continuous training (MICT), which has been shown by many studies to be beneficial to both mother and fetus by reducing preeclampsia, gestational diabetes, and depression. Although MICT has been shown to be effective, only 15% of individuals meet the recommended 150-minutes-a-week threshold for MICT; many individuals report their main obstacle as lack of time.

The effect of acute high-intensity interval training and Tabata training on inhibitory control and cortical activation in young adults.

Physical exercise not only benefits peoples' health, but also improves their cognitive function. Although growing evidence suggests that high-intensity interval training (HIIT) is a time-efficient exercise regime that can improve inhibitory control performance by enhancing cortical activation in the prefrontal cortex, less is known about how Tabata training, a subset of HIIT that requires no equipment or facilities to perform, affects inhibitory control and cortical activation in young adults. Therefore, we aimed to reveal the effect of an acute bout of HIIT and Tabata training on inhibitory control and attempted to identify its potential neural substrates. Forty-two young adults (mean age: 19.36 ± 1.36 years; 21 females) performed the Stroop task and Simon task before and after acute HIIT, Tabata training, or a control session, and cortical hemodynamic changes in the prefrontal area were monitored by functional near-infrared spectroscopy (fNIRS) during the tasks. Both HIIT and Tabata interventions lasted for a total of 12 min. The HIIT participants performed ergometer cycling at their 80% maximal aerobic power at 90-100 rpm, and the Tabata participants performed a total of 8 intense activities, such as jumping jacks, high knees, and butt kickers, without using equipment or facilities, keeping the heart rate at 80-95% of their maximum heart rate. Participants in the control group watched a sport video while sedentary. Cognitive tasks data and fNIRS data were analyzed by repeated-measures three-way ANOVA. Our results indicated that both the HIIT and Tabata groups exhibited reduced reaction times after the intervention, and there were alterations in activation patterns in the dorsolateral and ventrolateral prefrontal cortices.

Maternal And Fetal Cardiovascular Responses To Acute High-intensity Interval And Moderate-intensity Continuous Training Exercise

Maternal And Fetal Cardiovascular Responses To Acute High-intensity Interval And Moderate-intensity Continuous Training Exercise

Effect of Acute High-Intensity Interval Training on Immune Function and Oxidative Stress in Canoe/Kayak Athletes.

The aim of this study was to investigate the effects of acute high-intensity interval training (HIIT) on immune function and oxidative stress in male canoe/kayak athletes who were well trained. A total of 22 participants were voluntarily recruited with an age range of 15.9 ± 2.3 years, height of 172.2 ± 5.5 cm, body mass of 63.30 ± 6.95 kg, and body fat of 13.77 ± 3.76%. The modified Wingate kayaking test on a kayak ergometer was performed by all participants. Blood samples were collected at three different time points: before the test (Pre-T), immediately after (Post-T), and 3 h post-test (Post-3 h). Saliva samples were collected at two different time points: before the test (Pre-T) and 3 h after the test (Post-3 h). Results indicated that acute canoe/kayak ergometry HIIT had significant effects on the percentages and counts of leukocytes, neutrophils, lymphocytes, and lymphocyte subsets. Additionally, it resulted in increased total LPS-stimulated neutrophil elastase release and alterations in plasma concentrations of superoxide dismutase, catalase, and TBARS. These findings suggest that conventional kayak HIIT regimens can have short-term effects on immune function and induce oxidative stress in athletes.

Oral pyruvate prevents high-intensity interval exercise-induced metabolic acidosis in rats by promoting lactate dehydrogenase reaction.

There is no denying the clinical benefits of exogenous pyruvate in the treatment of pathological metabolic acidosis. However, whether it can prevent exercise physiological metabolic acidosis, delay the occurrence of exercise fatigue, and improve the beneficial effects of exercise and its internal mechanism remain unclear. We randomly divided 24 male SD rats into 3 groups: one group was a control without exercise (CC, n = 8), and the other two groups were supplemented with 616 mg/kg/day pyruvate (EP, n = 8) or distilled water of equal volume (EC, n = 8). These groups completed acute high-intensity interval exercise (HIIE) after 7 days of supplementation. The acid metabolism variables were measured immediately after exercise including blood pH (pHe), base excess (BE), HCO3 -, blood lactic acid and skeletal muscle pH (pHi). The redox state was determined by measuring the oxidized coenzyme I/reduced coenzyme I (nicotinamide adenine dinucleotide [NAD+]/reduced NAD+ [NADH]) ratio and lactate/pyruvate (L/P) ratio. In addition, the activities of lactate dehydrogenase A (LDHA), hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) were determined by ELISA. Pyruvate supplementation significantly reversed the decrease of pHe, BE, HCO3 - and pHi values after HIIE (p < 0.001), while significantly increased the activities of LDHA (p = 0.048), HK (p = 0.006), and PFK (p = 0.047). Compared with the CC, the NAD+/NADH (p = 0.008) ratio and the activities of LDHA (p = 0.002), HK (p < 0.001), PFK (p < 0.001), and PK (p = 0.006) were significantly improved in EP group. This study provides compelling evidence that oral pyruvate attenuates HIIE-induced intracellular and extracellular acidification, possibly due to increased activity of LDHA, which promotes the absorption of H+ in the LDH reaction. The beneficial effects of improving the redox state and glycolysis rate were also shown. Our results suggest that pyruvate can be used as an oral nutritional supplement to buffer HIIE induced metabolic acidosis.

The influence of exercise volume and posture on exercise-induced plasma volume expansion.

Acute high-intensity interval exercise is known to expand plasma volume 24 h after exercise. Upright exercise posture plays a role in expanding plasma volume by influencing lymphatic outflow and redistributing albumin while supine exercise does not. We examined if further upright and weight-bearing exercises could further promote plasma volume expansion. We also tested the volume of intervals needed to induce plasma volume expansion. To test the first hypothesis, 10 subjects performed intermittent high-intensity exercise (4min at 85% V̇O2max , 5min at 40% V̇O2max repeated 8 times) on separate days on the treadmill and cycle ergometer. For the second study, 10 subjects performed four, six, and eight intervals of the same interval protocol on separate days. Changes in plasma volume were calculated from changes in hematocrit and hemoglobin. Transthoracic impedance (Z0 ) and plasma albumin were assessed while seated before and postexercise. Plasma volume increased 7.3% ± 4.4% and 6.3% ± 3.5% following treadmill and cycle ergometer exercise, respectively. For four, six, and eight intervals, plasma volume increased by 6.6% ± 4.0%, 4.7% ± 2.6%, and 4.2% ± 5.6%, respectively. The increases in plasma volume were similar for both exercise modes and all three exercise volumes. There were no differences in Z0 or plasma albumin content between trials. In conclusion, rapid plasma volume expansion following eight bouts of high-intensity intervals appears to be independent of upright exercise posture (treadmill versus cycle ergometer). Meanwhile, plasma volume expansion was similar after four, six, and eight intervals of cycle ergometry.