Acute High-intensity Interval Training Research Articles

Acute High-intensity Interval Training And Moderate-intensity Continuous Exercises Differentially Facilitate Cognitive Control

PURPOSE: The present study investigated the effects of a single bout of high-intensity interval training (HIIT) and continuous, moderate aerobic exercise (MAE) on inhibitory control. METHODS: The P3 component of an event-related brain potential was collected in 64 young adults during a modified flanker task following 20 minutes of seated rest, 20 minutes of MAE, and 9 minutes of HIIT on separate days in counterbalanced order. RESULTS: Shorter overall reaction time was observed following MAE (392.2ms) and HIIT (384.8ms) compared to seated rest (402.6ms), t’s(63) ≥ 2.8, p’s ≤ .007. Response accuracy selectively improved following HIIT (93.2%) in the task condition requiring greater inhibitory control compared to seated rest (91.1%) and MAE (91.3%), t’s(63) ≥ 3.0, p’s ≤ .004. P3 amplitude was larger following MAE (14.4μV) compared to seated rest (13.1μV) and HIIT (11.6μV), t’s(63) ≥ 2.7, p’s ≤ .007. Decreased P3 amplitude and shorter latency were observed following HIIT (11.6μV; 393.6ms) compared to seated rest (13.1μV; 405.4ms), t’s(63) ≥ 2.6, p’s ≤ .012. CONCLUSION: The current results indicated that MAE may facilitate cognitive control via increased neural resource allocation, whereas HIIT may have a larger facilitation on cognitive control beyond MAE via more efficient neural resource allocation. These findings demonstrate that both single bouts of MAE and HIIT may be feasible approaches to enhance cognitive performance, albeit via different mechanisms of neural activation.

Examining the Impact of Different Exercise Protocols on PGC‐1α and FNDC5 mRNA Expression in Human Skeletal Muscle

A recent overexpression model demonstrated that peroxisome proliferator‐activated receptor coactivator 1‐alpha (PGC‐1α) regulates the expression of fibronectin type III domain containing protein 5 (FNDC5); a novel myokine with a potential role in stimulating brown‐fat‐like development in white adipose tissue. Although FNDC5 mRNA expression remains unaltered following an acute bout of endurance exercise (END) and high intensity interval training (HIIT), it is unclear whether FNDC5 mRNA expression increases following aerobic exercise protocols that demonstrate elevations in PGC‐1α mRNA expression. Therefore, the purpose of the present study was to test the hypothesis that aerobic exercise protocols that increase PGC‐1α mRNA expression will concomitantly increase FNDC5 mRNA expression in human skeletal muscle. Skeletal muscle biopsies were obtained from healthy men at rest (PRE) and three hours after one bout of moderate intensity interval exercise (MIIT; n = 10; 11 one‐minute intervals at 73% WR at VO2peak separated with one‐minute rest periods), HIIT (n = 10; 8 one‐minute intervals at 100% WR at VO2peak separated with one‐minute rest periods), or sprint interval training (SIT; n = 14; 8 20‐second intervals at 170% WR at VO2peak separated with 10 second rest periods). All samples and PGC‐1α mRNA expression data were obtained from previously published studies (1,2). PGC‐1α mRNA expression significantly (p < 0.05) increased following MIIT (+393% ± 345%), HIIT (+720% ± 392%), and SIT (+284% ± 140%). However, FNDC5 mRNA expression did not change following acute MIIT (−8% ± 29%, p = 0.3), HIIT (+16% ± 32%, p = 0.3), or SIT (−5% ± 18%, p = 0.3). Furthermore, changes in PGC‐1α and FNDC5 mRNA expression did not significantly correlate following any exercise protocol. This study demonstrates that although PGC‐1α mRNA expression increased following all exercise protocols, FNDC5 mRNA did not change. Therefore, these results suggest that interval exercise protocols that induce increases in PGC‐1α mRNA expression do not increase FNDC5 mRNA expression.Support or Funding InformationThis study was supported by funding from the Natural Sciences and Engineering Research Council of Canada (NSERC) to J.T.B., J. P. L., and B.J.G. B. A. E. and T. D. S. were supported by Ontario Graduate Scholarships. J. P. L. was also supported by a Canadian Institutes of Health Research (CIHR) New Investigator Award.

Sleep quality and high intensity interval training at two different times of day: A crossover study on the influence of the chronotype in male collegiate soccer players

ABSTRACTThe influence of the chronotype on the sleep quality in male collegiate soccer players in response to acute high intensity interval training (HIIT) performed at two different times of day was evaluated. The sleep quality was poorer in the morning-type than in the evening-type players after the evening HIIT session, whereas no significant changes in the sleep quality of the two chronotypes after the morning HIIT session was observed. The results suggest that an athlete’s chronotype should be taken into account when scheduling training sessions and to promote faster recovery processes.

Perceptual Changes in Response to Two Regimens of Interval Training in Sedentary Women.

This study examined acute and chronic changes in perceptual measures (rating of perceived exertion [RPE], affect, and arousal) in response to 2 regimens of high-intensity interval training (HIIT). Twenty-three healthy sedentary women (mean ± SD age and V[Combining Dot Above]O2max = 23.0 ± 5.7 years and 30.1 ± 4.4 ml·kg·min, respectively) were randomized to complete 12 weeks of one of 2 HIIT regimes, whereas an additional 7 women served as sedentary controls. Training was performed 3 days per week on a cycle ergometer and consisted of up to ten 1-minute bouts at moderate (60-80%Wmax = moderate intensity [MOD]) or more intense (80-90%Wmax = HI) workloads separated by active recovery. At baseline and every 3 weeks, RPE, affect, and arousal were measured during training using validated scales. Repeated measures analysis of variance was used to examine acute and chronic changes in these variables to HIIT. Data revealed significant (p < 0.001) increases in RPE and arousal and decreases (p < 0.001) in affect during acute HIIT, with RPE responses differing (p ≤ 0.05) between HI and MOD. However, acute changes in affect and arousal were similar in HI and MOD. Training led to a significant reduction in RPE, whereas both affect and arousal were unchanged (p > 0.05) after HIIT. Completion of moderate or more intense interval training reduces perceptions of RPE during training yet does not alter arousal or affect. RPE was reduced via training, yet large dependence on anaerobic metabolism during HIIT may minimize training-induced changes in affect.

Determination of Atherosclerosis markers changes after HIIT and ginger consumption in response to acute exercise in overweight women

The purpose of this study was to determine the effects of ten weeks of high intensity interval training (HIIT) with ginger supplementation on the systemic inflammatory response to acute HIIT exercise.Twenty four sedentary overweight women randomly assigned into three groups’ including HIIT + ginger (n=8), HIIT + placebo (n=8) and ginger (n=8). Sixteen women performed ten weeks of HIIT while the supplement consuming groups daily took 3 gm. of ginger pills and the HIIT + placebo group took placebo. Serum samples were collected at rest and immediately post-acute exercise, before and after the training. Two-way repeated measures ANOVA, paired t test, one-way ANOVA and post hoc benferoni were used to analyze data. Results indicated that three groups similarly affect the Monocyte Chemo tactic proetein-1 (MCP-1), Interlukine-10 (IL-10) changes in response to acute exercise (p>0.05) but showed significant increase in intercellular adhesion molecule-1 (ICAM-1) in HIIT + placebo group in comparison with HIIT + ginger group (p=0.02) in second acute exercise. The combination of HIIT and ginger consumption may induce a modest inflammatory attenuation of atherosclerosis factors in response to acute exercise and improvement in Vo2max and PBF results rather than ginger and training alone, in young sedentary overweight women.

Autonomic Function Predicts Fitness Response to Short-Term High-Intensity Interval Training.

We tested the hypothesis that baseline cardiac autonomic function and its acute response to all-out interval exercise explains individual fitness responses to high-intensity interval training (HIT). Healthy middle-aged sedentary men performed HIT (n=12, 4-6×30 s of all-out cycling efforts with 4-min recovery) or aerobic training (AET, n=9, 40-60 min at 60% of peak workload in exercise test [Loadpeak]), comprising 6 sessions within 2 weeks. Low (LF) and high frequency (HF) power of R-R interval oscillation were analyzed from data recorded at supine and standing position (5+5 min) every morning during the intervention. A significant training effect (p< 0.001), without a training*group interaction, was observed in Loadpeak and peak oxygen consumption (VO2peak). Pre-training supine LF/HF ratio, an estimate of sympathovagal balance, correlated with training outcome in Loadpeak (Spearman's rho [rs]=-0.74, p=0.006) and VO2peak (rs=- 0.59, p=0.042) in the HIT but not the AET group. Also, the mean change in the standing LF/HF ratio in the morning after an acute HIT exercise during the 1(st) week of intervention correlated with training response in Loadpeak (rs=- 0.68, p=0.014) and VO2peak (rs=-0.60, p=0.039) with HIT but not with AET. In conclusion, pre-training cardiac sympathovagal balance and its initial alterations in response to acute HIT exercise were related to fitness responses to short-term HIT.

Acute molecular responses to concurrent resistance and high-intensity interval exercise in untrained skeletal muscle.

Concurrent training involving resistance and endurance exercise may augment the benefits of single-mode training for the purpose of improving health. However, muscle adaptations, associated with resistance exercise, may be blunted by a subsequent bout of endurance exercise, via molecular interference. High-intensity interval training (HIIT), generating similar adaptations to endurance exercise, may offer an alternative exercise mode to traditional endurance exercise. This study examined the influence of an acute HIIT session on the molecular responses following resistance exercise in untrained skeletal muscle. Ten male participants performed resistance exercise (4 × 8 leg extensions, 70% 1RM, (RE)) or RE followed by HIIT (10 × 1 min at 90% HRmax, (RE+HIIT)). Muscle biopsies were collected from the vastus lateralis before, 2 and 6 h post-RE to determine intramuscular protein phosphorylation and mRNA responses. Phosphorylation of Akt (Ser473) decreased at 6 h in both trials (P < 0.05). Phosphorylation of mTOR (Ser2448) was higher in RE+HIIT (P < 0.05). All PGC-1α mRNA variants increased at 2 h in RE+HIIT with PGC-1α and PGC-1α-ex1b remaining elevated at 6 h, whereas RE-induced increases at 2 and 6 h for PGC-1α-ex1b only (P < 0.05). Myostatin expression decreased at 2 and 6 h in both trials (P < 0.05). MuRF-1 was elevated in RE+HIIT versus RE at 2 and 6 h (P < 0.05). Atrogin-1 was lower at 2 h, with FOXO3A downregulated at 6 h (P < 0.05). These data do not support the existence of an acute interference effect on protein signaling and mRNA expression, and suggest that HIIT may be an alternative to endurance exercise when performed after resistance exercise in the same training session to optimize adaptations.

Postexercise Cold Water Immersion Benefits Are Not Greater than the Placebo Effect

Despite a general lack of understanding of the underlying mechanisms, cold water immersion (CWI) is widely used by athletes for recovery. This study examined the physiological merit of CWI for recovery from high-intensity exercise by investigating if the placebo effect is responsible for any acute performance or psychological benefits. Thirty males (mean ± SD: age, 24 ± 5 yr; VO2 peak, 51.1 ± 7.0 mL · kg(-1) · min(-1)) performed an acute high-intensity interval training session, comprised of 4 × 30-s sprints, immediately followed by one of the following three 15-min recovery conditions: CWI (10.3°C ± 0.2°C), thermoneutral water immersion placebo (TWP) (34.7°C ± 0.1°C), or thermoneutral water immersion control (TWI) (34.7°C ± 0.1°C). An intramuscular thermistor was inserted during exercise and recovery to record muscle temperature. Swelling (thigh girth), pain threshold/tolerance, interleukin 6 concentration, and total leukocyte, neutrophil, and lymphocyte counts were recorded at baseline, postexercise, postrecovery, and 1, 24, and 48 h postexercise. A maximal voluntary isometric contraction (MVC) of the quadriceps was performed at the same time points, with the exception of postexercise. Self-assessments of readiness for exercise, fatigue, vigor, sleepiness, pain, and belief of recovery effectiveness were also completed. Leg strength after the MVC and ratings of readiness for exercise, pain, and vigor were significantly impaired in TWI compared with those in CWI and TWP which were similar to each other. A recovery placebo administered after an acute high-intensity interval training session is superior in the recovery of muscle strength over 48 h as compared with TWI and is as effective as CWI. This can be attributed to improved ratings of readiness for exercise, pain, and vigor, suggesting that the commonly hypothesized physiological benefits surrounding CWI are at least partly placebo related.

Influence of acute high-intensity aerobic interval exercise bout on selective attention and short-term memory tasks.

Acute moderate intensity continuous aerobic exercise can improve specific cognitive functions, such as short-term memory and selective attention. Moreover, high-intensity interval training (HIT) has been recently proposed as a time-efficient alternative to traditional cardiorespiratory exercise. However, considering previous speculations that the exercise intensity affects cognition in a U-shaped fashion, it was hypothesized that a HIT session may impair cognitive performance. Therefore, this study assessed the effects of an acute HIT session on selective attention and short-term memory tasks. 22 healthy middle-aged individuals (M age = 53.7 yr.) engaged in both (1) a HIT session, 10 1 min. cycling bouts at the intensity corresponding to 80% of the reserve heart rate interspersed by 1 min. active pauses cycling at 60% of the reserve heart rate and (2) a control session, consisting of an active condition with low-intensity active stretching exercise. Before and after each experimental session, cognitive performance was assessed by the Victoria Version of the Stroop test (a selective attention test) and the Digit Span test (a short-term memory test). Following the HIT session, the time to complete the Stroop "Color word" test was significantly lower when compared with that of the control session. The performances in the other subtasks of the Stroop test as well as in the Digit Span test were not significantly different. A HIT session can improve cognitive function.

Low‐volume high intensity interval training induces a modest inflammatory response in young active males

Prolonged, high intensity aerobic exercise induces a substantial systemic inflammatory response. High intensity interval training (HIIT) is a time‐effective exercise strategy for improving physiological systems; however, the inflammatory response to short‐term HIIT is not well known. Recreationally active, males (18–25 yrs) underwent 2 weeks of low‐volume HIIT (6 sessions at 8–12 intervals; 60 sec intervals) at a power output equivalent to 100% of their pre‐determined VO2max. Serum samples were analyzed for inflammatory cytokines at rest, immediately after, and 15, 30, and 45 min after completion of an acute HIIT session before and after 2 weeks of HIIT, using a bead‐based multiplex cytokine assay. HIIT induced 2–3‐fold increases in IL‐6 (main effect of time; p&lt;0.001), a 2‐fold increase in IL‐8 (main effect of time; p=0.038), a 2‐fold increase in IL‐10 (main effect of time; p=0.02), a 55% increase in TNFα (main effect of time; p=0.028), and a 30% increase in MCP‐1 (main effect of time; p=0.018), compared to rest. The concentrations of IFNγ, GM‐CSF, and IL‐1β were unaltered with HIIT. These results suggest that young healthy subjects undergoing an acute session of low‐volume HIIT induces a modest, yet significant inflammatory response; however, 2 weeks of HIIT does not appear to alter this response.

Acute high‐intensity interval exercise reduces the postprandial glucose response and prevalence of hyperglycaemia in patients with type 2 diabetes

High-volume endurance exercise (END) improves glycaemic control in type 2 diabetes (T2D) but many individuals cite 'lack of time' as a barrier to regular participation. High-intensity interval training (HIT) is a time-efficient method to induce physiological adaptations similar to END, but little is known regarding the effect of HIT in T2D. Using continuous glucose monitoring (CGM), we examined the 24-h blood glucose response to one session of HIT consisting of 10 × 60 s cycling efforts at ~90% maximal heart rate, interspersed with 60 s rest. Seven adults with T2D underwent CGM for 24-h on two occasions under standard dietary conditions: following acute HIT and on a non-exercise control day (CTL). HIT reduced hyperglycaemia measured as proportion of time spent above 10 mmol/l (HIT: 4.5 ± 4.4 vs. CTL: 15.2 ± 12.3%, p = 0.04). Postprandial hyperglycaemia, measured as the sum of post-meal areas under the glucose curve, was also lower after HIT vs. CTL (728 ± 331 vs. 1142 ± 556 mmol/l·9 h, p = 0.01). These findings highlight the potential for HIT to improve glycaemic control in T2D.

Acute high-intensity interval training improves Tvent and peak power output in highly trained males.

This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake (VO2peak), the first and second ventilatory thresholds (VT1, VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists (VO2peak = 67.5 +/- 3.7 ml.kg-1.min-1) performed a ramped cycle test to determine VO2peak, VT1, VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 x 60 s at PPO, 120 s recovery); the VO2peak test was repeated < 1 wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in VO2peak for either group; however, the HIT group showed a significantly greater increase in VT1 (+22% vs. -3%), VT2 (+15% vs. -1%), and PPO (+4.3 vs. -.4%) compared to controls (all P < .05). This study has demonstrated that HIT can improve VT1, VT2, and PPO, following only four HIT sessions in already highly trained cyclists.