Min Of High-intensity Exercise Research Articles

High Intensity Intermittent Exercise Plays a Role in Improving Brain Activation During Complex Executive Functional Tasks

Several neuroimaging studies have examined the effect of different types and combinations of exercises on activation of brain associated with cognitive testing but none of these studies have examined the role of high intensity intermittent exercise (HIIE) in altering cortical activation from simple to complex cognitive tasks. 
 The purpose of this study was to find if HIIE has a role in modulating executive functions related to inhibitory control as expressed by changes in prefrontal cortex (PFC) activation. 
 Materials and methods. 40 healthy adults aged between 18-30 years volunteered for the study. They were randomly divided into HIIE a (n = 20) group and a control (n = 20) group. The HIIE group performed 4*4 min of high intensity exercise on a cycle ergometer with 3 minutes of active recovery at lower intensities between the bouts, whereas the control group performed no exercise. Prefrontal hemodynamics (oxy and deoxy haemoglobin) were assessed using functional near infrared spectroscopy (fNIRS) during the Colour Word Stroop test (CWST) on two sessions: pre-session and post-session (1 week after pre-session).
 Results. The results indicate a significant difference in CWST scores which coincided with a significant difference in hemodynamics of PFC between a congruent and a complex incongruent task in the HIIE group. There was a greater activation of the right frontopolar area, the left ventrolateral prefrontal cortex, and the left frontopolar area during the incongruent task in response to acute HIIE. 
 Conclusion. HIIE plays a role in changing brain activation during more complex interference related tasks.

Serum levels of interleukin-6 (IL-6), IL-10, and lactate in response to combat physical fitness test

The aim of the study is to investigate serum levels of interleukin-6 (IL-6), IL-10 and lactate in response to combat physical fitness test. 20 volunteer (26.95 years, BMI: 22.13 ± 2.78 kg/m2) subjects were engaged to participate the test consisted: (1) 25-yd sprint to J-hook, to 25-yd crawl, and 25-yd run through cones to 75-yd line; split (2) 75-yd casualty drag; split (3) ammo can run to grenade toss (75-yd); (4) ammo can run to end (75-yd); and (5) 650 yard endurance run. Blood was drawn before and after exercise, and circulating IL-6 and IL-10 as well as plasma levels of lactate were assessed. The levels of IL-6 and IL-10 were determined by enzyme-linked immunosorbent assay. The results of the pre-test and post-test variables show: post-test heart rate and blood lactate were significantly elevated due to combat test (p = 0.001). Plasma interleukin 6 increased significantly after combat-related test (p = 0.003), but interleukin 10 had no dramatic change after the test. There were strongly significant correlations between post-test IL-6 and lactate levels (P < 0.001, r = − 0.591). In conclusion, it suggested that IL-6 is responsive to short-term maximal power output required in combat readiness test. However, it appears that 3–4 min of high-intensity exercise induces comparatively moderate post-exercise increment in IL-6, which appears to be inadequate to activate the systemic anti-inflammatory influences that are mediated via secondary IL-6-activated up-regulation of anti-inflammatory signaling myokines such as IL-10.

12 min/week of high-intensity interval training reduces aortic reservoir pressure in individuals with metabolic syndrome: a randomized trial.

Decreased aortic reservoir function leads to a rise in aortic reservoir pressure that is an independent predictor of cardiovascular events. Although there is evidence that high-intensity interval training (HIIT) would be useful to improve aortic reservoir pressure, the optimal dose of high-intensity exercise to improve aortic reservoir function has yet to be investigated. Therefore, this study compared the effect of different volumes of HIIT and moderate-intensity continuous training (MICT) on aortic reservoir pressure in participants with the metabolic syndrome (MetS). Fifty individuals with MetS were randomized into one of the following 16-week training programs: MICT [n = 17, 30 min at 60-70% peak heart rate (HRpeak), five times/week]; 4 × 4-min high-intensity interval training (4HIIT) (n = 15, 4 × 4 min bouts at 85-95% HRpeak, interspersed with 3 min of active recovery at 50-70% HRpeak, three times/week); and 1 × 4-min high-intensity interval training (1HIIT) (n = 18, 1 × 4 min bout at 85-95% HRpeak, three times/week). Aortic reservoir pressure was calculated from radial applanation tonometry. Although not statistically significant, there was a trend for a small-to-medium group × time interaction effect on aortic reservoir pressure, indicating a positive adaptation following 1HIIT compared with 4HIIT and MICT [F (2,46) = 2.9, P = 0.07, η = 0.06]. This is supported by our within-group analysis wherein only 1HIIT significantly decreased aortic reservoir pressure from pre to postintervention (pre-post: 1HIIT 33 ± 16 to 31 ± 13, P = 0.03; MICT 29 ± 9-28 ± 8, P = 0.78; 4HIIT 28 ± 10-30 ± 9 mmHg, P = 0.10). Three sessions of 4 min of high-intensity exercise per week (12 min/week) was sufficient to improve aortic reservoir pressure, and thus may be a time-efficient exercise modality for reducing cardiovascular risk in individuals with MetS.

Short-term high-intensity interval exercise training attenuates oxidative stress responses and improves antioxidant status in healthy humans

This study investigated the changes in oxidative stress biomarkers and antioxidant status indices caused by a 3-week high-intensity interval training (HIT) regimen. Eight physically active males performed three HIT sessions/week over 3 weeks. Each session included four to six 30-s bouts of high-intensity cycling separated by 4 min of recovery. Before training, acute exercise elevated protein carbonyls (PC), thiobarbituric acid reactive substances (TBARS), glutathione peroxidase (GPX) activity, total antioxidant capacity (TAC) and creatine kinase (CK), which peaked 24h post-exercise (252 ± 30%, 135 ± 17%, 10 ± 2%, 85 ± 14% and 36 ± 13%, above baseline, respectively; p<0.01), while catalase activity (CAT) peaked 30 min post-exercise (56 ± 18% above baseline; p<0.01). Training attenuated the exercise-induced increase in oxidative stress markers (PC by 13.3 ± 3.7%; TBARS by 7.2 ± 2.7%, p<0.01) and CK activity, despite the fact that total work done was 10.9 ± 3.6% greater in the post- compared with the pre-training exercise test. Training also induced a marked elevation of antioxidant status indices (TAC by 38.4 ± 7.2%; CAT by 26.2 ± 10.1%; GPX by 3.0 ± 0.6%, p<0.01). Short-term HIT attenuates oxidative stress and up-regulates antioxidant activity after only nine training sessions totaling 22 min of high intensity exercise, further supporting its positive effect not only on physical conditioning but also on health promotion.

Inhalation of Combustion Derived Particulate Matter During 30 Min Exercise Does Not Affect Lung Function

PURPOSE: Associations between high particulate matter (PM) pollution from fossil fuel emissions and lung dysfunction and new-onset asthma have been identified for chronic exposure exercise. Likewise, decreased lung function has been shown in asthmatics after acute bouts of exercise in high PM. We hypothesized that an acute bout of high PM1 exercise would result in significant decrease in FEV1 and montelukast (MK), a leukotriene receptor antagonist, would attenuate that decrease. The purpose of this study was to assess the effects of PM inhalation during high intensity short term exercise in healthy male subjects. METHODS: Ten healthy males exercised in an exposure chamber 4 times for 30 min in both high [550,286±42,004/cm3] and low PM1 [4,571±1,922/cm3] air after taking placebo (PL) or 10 mg MK (half-life 3-6 h). Lung function was measured by spirometry pre-, 5, 10, 50 min, 4 h, 24 h post- exercise. RESULTS: Baseline FEV1 was normal (103% predicted) and consistent among trials. An acute bout of exercise in high PM1 conditions did not result in decreased lung function up to 24 h post exercise. No difference in post-exercise FEV1 was noted between PM1 conditions or treatment (PL or MK).TableCONCLUSION: An acute bout of 30 min exercise in high PM1 conditions does not decrease lung function in healthy college-aged males. Whether 30 min of high intensity exercise in high PM1 conditions results in inflammatory mediator release is yet to be determined. AHA 0455734U

Hormonal responses to physical and cognitive stress in a school setting

Little is known about the influence of physical and cognitive stress on the concentration of steroid hormones (SHs) in a school setting. Forty high school students from the 9th grade were randomly assigned to two intervention groups: physical and cognitive stress. Saliva collection took place before (pre-test) and after (post-test) 12min of high intensity exercise in a defined heart rate (HR) interval (70–85% HR max; n=19) and cognitive testing (Letter Digit Span and d2-test, n=21), respectively. Saliva was analyzed for testosterone (T) and cortisol (C). Results indicated a significant increase of T and C due to a physical but not cognitive stressor. Thus, only the physical stressor was capable of activating the hypothalamic–pituitary–adrenal (HPA) and the hypothalamic–pituitary–gonadal (HPG) axis.

A PROTEOMIC ANALYSIS OF THE ACUTE EFFECTS OF HIGH‐INTENSITY EXERCISE ON SKELETAL MUSCLE PROTEINS IN FASTED RATS

Quantitative proteomics is a technique that allows for large-scale comparison of the levels of individual proteins present in a biological sample. This technique has not previously been applied to examine the response of skeletal muscle proteins to an acute bout of exercise. In the present study, quantitative proteomics was applied to investigate whether the levels of individual skeletal muscle proteins are acutely affected by a short bout of high-intensity exercise. Gastrocnemius muscle was sampled from fasted rats either at rest, immediately following 3 min of high-intensity exercise or after 30 min of recovery. Muscle samples were submitted to two-dimensional gel electrophoresis and 61 of the resulting protein spots were selected for quantitative analysis. It was found that skeletal muscle protein levels were generally not acutely affected by a short bout of high-intensity exercise, with only four of the 61 proteins selected for analysis being significantly altered. These altered proteins were identified using liquid chromatography electrospray ionization-tandem mass spectrometry as creatine kinase, troponin T and a combination of heat shock 20 kDa protein and adenylate kinase 1. In conclusion, quantitative proteomics is sensitive enough to detect acute changes in skeletal muscle protein levels in response to exercise. We have found that the levels of most individual skeletal muscle proteins are not immediately altered in response to a short bout of high-intensity exercise and recovery in fasted rats.

Effect of low and high intensity exercise on circulating growth hormone in men.

We hypothesized that circulating GH would increase only if a threshold of work intensity [corresponding to the anaerobic or lactate threshold (LT)] was exceeded. Ten healthy male volunteers (18-35 yr) first performed ramp-type progressive cycle-ergometer exercise to determine the LT and the maximal oxygen uptake. On subsequent mornings after an overnight fast, each subject performed bouts of 1, 5, and 10 min constant work rate exercise of either high intensity (above LT) or low intensity (below LT). A 1-h interval separated exercise bouts. Gas exchange (breath-by-breath), GH, immunoreactive insulin, glucose, lactate, pyruvate, and epinephrine and norepinephrine were measured at regular intervals. After the 10-min bouts of high compared with low intensity exercise, lactate was 7.2 +/- 3.7 mmol/L vs. 1.4 +/- 1.3, P less than 0.05; epinephrine was 1,113 +/- 519 pmol/L vs. 496 +/- 273, P less than 0.05; and norepinephrine was 7.89 +/- 3.45 nmole/L vs. 2.83 +/- 1.34, P less than 0.05. GH did not increase significantly from preexercise baseline during low intensity exercise (e.g., GH after 10-min low intensity exercise changed from baseline values by 1.5 +/- 2.0 micrograms/L, NS). Although lactate was elevated after 5-min of high intensity exercise, peak GH was significantly elevated (mean increase above baseline of 7.7 +/- 2.4 micrograms/L, P less than 0.05) only after 10 min of high intensity exercise (increases in 9 of 10 subjects). The GH increase occurred despite simultaneous increases in both IRI and glucose. A minimum duration of 10 min, high intensity exercise consistently increased circulating GH in adult males.

Effects of supramaximal exercise on blood glucose levels during a subsequent exercise

The purpose of the present investigation was to examine the effects of hyperglycemia induced by supramaximal exercise on blood glucose homeostasis during submaximal exercise following immediately after. Six men were subjected to three experimental situations; in two of these situations, 3 min of high-intensity exercise (corresponding to 112, SD 1% VO2max) was immediately followed by either a 60-min period of submaximal exercise (68, SD 2% VO2max) or a 60-min resting period. In the third situation, subjects performed a 63-min period of submaximal exercise only. There were no significant differences between the heart rates, oxygen uptakes, and respiratory exchange ratios during the two submaximal exercise bouts (greater than 15 min) whether or not preceded by supramaximal exercise. The supramaximal exercise was associated within 10 min of the start increases (P less than 0.05) in blood glucose, insulin, and lactate concentrations. This hyperglycemia was more pronounced when subjects continued to exercise submaximally than when they rested (at 7.5 min; P less than 0.05). There was a more rapid return to normal exercise blood glucose and insulin values during submaximal exercise compared with rest. The data show that the hyperinsulinemia following supramaximal exercise is corrected in between 10-30 min during submaximal exercise following immediately, suggesting that this exercise combination does not lead to premature hypoglycemia.

Blood glucose turnover during high- and low-intensity exercise.

We hypothesized that whole body glucose uptake (Rd) during exercise is not related in a simple, linear manner to O2 uptake (VO2). To test this, seven healthy male subjects (age range 23-34 yr) were studied in the postabsorptive but not glycogen-depleted state. Three conditions were examined: 1) rest, 2) 40 min of constant exercise in which the work rates were carefully chosen to consist of low-intensity exercise (no elevated blood lactate, a mean of 40% maximal VO2), and 3) 40 min of high-intensity exercise (markedly elevated blood lactate, 79% maximal VO2). Gas exchange was measured breath by breath, and glucose uptake and production were measured using [6,6-2H2]glucose. Low-intensity exercise (n = 7) resulted in a small but not statistically significant increase in mean Rd [3.06 +/- 0.37 (SE) mg.min-1.kg-1] compared with resting values (2.87 +/- 0.39 mg.min-1.kg-1) despite a fourfold increase in the production of CO2 and VO2. By contrast, the high-intensity exercise Rd (n = 5, 6.98 +/- 0.67 mg.min-1.kg-1) was significantly greater than the resting value (3.03 +/- 0.56 mg.min-1.kg-1). Results of glucose production were virtually the same. Similarly, mean levels of epinephrine and norepinephrine increased significantly above resting values during high- but not low-intensity exercise. Our data demonstrate that whole body glucose dynamics and regulation during 40 min of exercise do not change in a simple linear manner with respect to metabolic rate.