TBC1D1 Ser237 phosphorylation, but not insulin sensitivity, is higher following a bout of high-intensity interval exercise in males as compared with females

Interval training has been found to lower glucose concentrations and increase insulin sensitivity in males but not females, which may be due to inherent sex-based differences in metabolism. Twenty-four (12/sex) participants completed a bout of high-intensity interval exercise (HIIE, 10x1min at 90% HR_max) to evaluate whether sex influenced the physiological effects of HIIE on post-exercise glycemic control during an oral glucose tolerance test (OGTT). Given that body anthropometrics influence postprandial glucose, data were also expressed as a function of the normalized glucose dose. Additionally, we examined whether sex differences in post-exercise glycemic control were related to sex differences in muscle metabolism and/or insulin signaling proteins. HIIE increased insulin sensitivity in both sexes as characterized by the Matsuda (p=0.03, η_p²=0.20) and HOMA-IR (p=0.047, η_p²=0.17) indices. HIIE also lowered insulin concentration during the OGTT (p=0.04, η_p²=0.18) as compared with control. When normalized for glucose dose relative to lean mass, glucose AUC was lower in females than males (p=0.001, η_p²=0.42). TBC1D1 Ser²³⁷ phosphorylation increased in males, but not females, post-exercise (p=0.02, η_p²=0.22). There was no difference in total insulin signaling protein content, muscle glycogen utilization or AMPK activation during exercise between the sexes. These findings indicate that when the glucose dose is normalized for differences in body composition glycemic handling is better in females and that an acute bout of HIIE improves insulin sensitivity equally in healthy males and females.

Effect of Menstrual Cycle Phase on the Recovery Process of High-Intensity Interval Exercise-A Cross-Sectional Observational Study

Although the study of the menstrual cycle influence on endurance exercise has recently increased, there is a lack of literature studying its influence on females' cardiorespiratory recovery. Thus, the aim of the present work was to assess menstrual cycle influence on post-exercise recovery following a high intensity interval exercise in trained females. Thirteen eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early follicular phase (EFP), late follicular phase (LFP), and mid-luteal phase (MLP). The protocol consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed (vVO2peak) with a 90-s rest between bouts and a final 5-min active recovery at 30% vVO2peak. All variables were averaged every 15 s, obtaining 19 moments during recovery (time factor). To analyze the effects of the menstrual cycle on the final active cardiorespiratory recovery, an ANOVA for repeated measures was performed. ANOVA showed an effect on menstrual cycle phase on ventilation (EFP: 1.27 ± 0.35; LFP: 1.19 ± 0.36; MLP: 1.27 ± 0.37), breathing frequency (EFP: 35.14 ± 7.14; LFP: 36.32 ± 7.11; MLP: 37.62 ± 7.23), and carbon dioxide production (EFP: 1120.46 ± 137.62; LFP: 1079.50 ± 129.57; MLP: 1148.78 ± 107.91). Regarding the interaction results (phase x time), ventilation is higher at many of the recovery times during the MLP, with less frequent differences between EFP and LFP (F = 1.586; p = 0.019), while breathing reserve is lower at many of the recovery times during MLP, with less time differences between EFP and LFP (F = 1.643; p = 0.013). It seems that the menstrual cycle affects post-exercise recovery specially during the MLP, rising ventilation and lowering breathing reserve, giving rise to an impaired ventilatory efficiency.

a Single Bout of Moderate Intensity Continuous Exercise in Adults With or Without Hypertension: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Background: Post-exercise hypotension (PEH) is an important tool in the daily management of patients with hypertension. Varying the exercise parameters is likely to change the blood pressure (BP) response following a bout of exercise. In recent years, high-intensity interval exercise (HIIE) has gained significant popularity in exercise-based prevention and rehabilitation of clinical populations. Yet, to date, it is not known whether a single session of HIIE maximizes PEH more than a bout of moderate-intensity continuous exercise (MICE).

Objective: To compare the effect of HIIE vs. MICE on PEH by means of a systematic review and meta-analysis.

Methods: A systematic search in the electronic databases MEDLINE, Embase, and SPORTDiscus was conducted from the earliest date available until February 24, 2020. Randomized clinical trials comparing the transient effect of a single bout of HIIE to MICE on office and/or ambulatory BP in humans (≥18 years) were included. Data were pooled using random effects models with summary data reported as weighted means and 95% confidence interval (CIs).

Results: Data from 14 trials were included, involving 18 comparisons between HIIE and MICE and 276 (193 males) participants. The immediate effects, measured as office BP at 30- and 60-min post-exercise, was similar for a bout of HIIE and MICE (p > 0.05 for systolic and diastolic BP). However, HIIE elicited a more pronounced BP reduction than MICE [(−5.3 mmHg (−7.3 to −3.3)/ −1.63 mmHg (−3.00 to −0.26)] during the subsequent hours of ambulatory daytime monitoring. No differences were observed for ambulatory nighttime BP (p > 0.05).

Conclusion: HIIE promoted a larger PEH than MICE on ambulatory daytime BP. However, the number of studies was low, patients were mostly young to middle-aged individuals, and only a few studies included patients with hypertension. Therefore, there is a need for studies that involve older individuals with hypertension and use ambulatory BP monitoring to confirm HIIE's superiority as a safe BP lowering intervention in today's clinical practice.

Systematic Review Registration: PROSPERO (registration number: CRD42020171640).

Menstrual Cycle Phases Influence on Cardiorespiratory Response to Exercise in Endurance-Trained Females

The aim of this study was to analyse the impact of sex hormone fluctuations throughout the menstrual cycle on cardiorespiratory response to high-intensity interval exercise in athletes. Twenty-one eumenorrheic endurance-trained females performed an interval running protocol in three menstrual cycle phases: early-follicular phase (EFP), late-follicular phase (LFP) and mid-luteal phase (MLP). It consisted of 8 × 3-min bouts at 85% of their maximal aerobic speed with 90-s recovery at 30% of their maximal aerobic speed. To verify menstrual cycle phase, we applied a three-step method: calendar-based counting, urinary luteinizing hormone measurement and serum hormone analysis. Mixed-linear model for repeated measures showed menstrual cycle impact on ventilatory (EFP: 78.61 ± 11.09; LFP: 76.45 ± 11.37; MLP: 78.59 ± 13.43) and heart rate (EFP: 167.29 ± 11.44; LFP: 169.89 ± 10.62; MLP: 169.89 ± 11.35) response to high-intensity interval exercise (F_2.59 = 4.300; p = 0.018 and F_2.61 = 4.648; p = 0.013, respectively). Oxygen consumption, carbon dioxide production, respiratory exchange ratio, breathing frequency, energy expenditure, relative perceived exertion and perceived readiness were unaltered by menstrual cycle phase. Most of the cardiorespiratory variables measured appear to be impassive by menstrual cycle phases throughout a high-intensity interval exercise in endurance-trained athletes. It seems that sex hormone fluctuations throughout the menstrual cycle are not high enough to disrupt tissues’ adjustments caused by the high-intensity exercise. Nevertheless, HR based training programs should consider menstrual cycle phase.

High Protein Pre-exercise Feedings on Psychophysiological Responses to High Intensity Interval Exercise in Overweight Perimenopausal Women

Objective: To investigate (a) the acute effect of a bout of high intensity interval exercise (HIIE) on mood, cognitive function, and blood pressure in overweight perimenopausal women and (b) to compare the effects of high carbohydrate vs. high protein pre-HIIE feedings on exercise capacity, mood and cognitive function in this population.

Methods: Twelve, overweight, perimenopausal women (age; 45.5 ± 2.3 years, body fat; 32.2 ± 2.1%) completed a bout of HIIE under 3 pre-exercise feedings (HCHO: high-carbohydrate-low-protein; LCHP: low-carbohydrate-high-protein; control: fasted) in a randomized crossover design. HIIE consisted of 4 intervals of 4 min walking at 85–90% of maximum heart rate and 3 min recovery. Before and after HIIE, the shortened version of the profile of mood state questionnaire, the exercise—induced feeling inventory questionnaire and three cognitive function tests (Stroop test, Shift Stroop test, n-back test) were administered. Blood pressure was measured pre- and post-exercise. Following HIIE a performance test to volitional fatigue was conducted.

Results: A single bout of HIIE resulted in significant reductions in blood pressure and improvements in cognitive capacity (p < 0.05). Both the HCHO and LCHP feedings led to significantly longer exercise performance compared to CON (422 ± 71 s and 340 ± 46 vs. 240 ± 32 s, respectively, p < 0.01), with a 1.22-fold greater increase in performance time in HCHO compared to LCHP, although not statistically significant (p > 0.05). Only the HCHO trial improved total mood disturbance and positive engagement 1 h-post-exercise compared to CON (p < 0.05). HCHO and LCHP improved physical exhaustion and revitalization feelings post-exercise vs. CON (p < 0.01).

Conclusions: A single HIIE session improves cognitive function and blood pressure in overweight perimenopausal women. High-carbohydrate pre-HIIE feedings can result in greater enhancements in mood and positive engagement to exercise and may improve exercise performance compared to a high-protein meal.

Circulatory exosomal miRNA following intense exercise is unrelated to muscle and plasma miRNA abundances

MicroRNAs (miRNAs) regulate gene expression via transcript degradation and translational inhibition, and they may also function as long distance signaling molecules. Circulatory miRNAs are either protein-bound or packaged within vesicles (exosomes). Ten young men (24.6 ± 4.0 yr) underwent a single bout of high-intensity interval cycling exercise. Vastus lateralis biopsies and plasma were collected immediately before and after exercise, as well as 4 h following the exercise bout. Twenty-nine miRNAs previously reported to be regulated by acute exercise were assessed within muscle, venous plasma, and enriched circulatory exosomes via qRT-PCR. Of the 29 targeted miRNAs, 11 were altered in muscle, 8 in plasma, and 9 in the exosome fraction. Although changes in muscle and plasma expression were bidirectional, all regulated exosomal miRNAs increased following exercise. Three miRNAs were altered in all three sample pools (miR-1-3p, -16-5p, and -222-3p), three in both muscle and plasma (miR-21-5p, -134-3p, and -107), three in both muscle and exosomes (miR-23a-3p, -208a-3p, and -150-5p), and three in both plasma and exosomes (miR-486-5p, -126-3p, and -378a-5p). There was a marked discrepancy between the observed alterations between sample pools. A subset of exosomal miRNAs increased in abundance following exercise, suggesting an exercise-induced release of exosomes enriched in specific miRNAs. The uniqueness of the exosomal miRNA response suggests its relevance as a sample pool that needs to be further explored in better understanding biological functions.

Acute Effects of High-Intensity Interval and Moderate-Intensity Continuous Exercise on GLP-1, Appetite and Energy Intake in Obese Men: A Crossover Trial

This study investigated the effect of high-intensity interval (HIIE) and moderate-intensity continuous exercise (MICE) on glucagon-like peptide 1 (GLP-1), appetite and energy intake (EI) in obese men. In a randomized crossover trial, 12 participants (28.4 ± 2.6 years, 35.5 ± 4.5 kg/m², 39.8 ± 2.2% body fat) performed: (I) Control (CON, no exercise); (II) MICE (20 min, 70% of maximal heart rate) and (III) HIIE (10 × 1 min at 90% of maximal heart rate with 1 min recovery). GLP-1 and appetite were assessed at: (I) PRE: pre-exercise; (II) POST: immediately post-exercise; (III) POST-1 h: 1 h post-exercise. EI was assessed after an ad libitum meal offered 1 h post-exercise and over 24 h. There was a significant time × condition interaction for GLP-1 (p = 0.035). Higher GLP-1 levels in MICE vs. CON (p = 0.024) and a trend for HIIE vs. CON (p = 0.069) POST-1h was found. Hunger was reduced immediately post-HIIE compared to CON (p < 0.01), but was not sustained POST-1 h (p > 0.05). EI did not differ between the sessions 1 h post-exercise or over 24H (p > 0.05). In summary, although MICE increased GLP-1 levels POST-1h and HIIE induced a transient reduction in hunger, both exercise protocols did not impact EI in obese men.

Cardiac Autonomic Modulation and the Kinetics of Heart Rate Responses in the On- and Off-Transient during Exercise in Women with Metabolic Syndrome

Objective: To test whether women with metabolic syndrome (MS) have impairments in the on- and off-transients during an incremental test and to study whether any of the MS components are independently associated with the observed responses.

Research Design and Methods: Thirty-six women aged 35–55 years were divided into a group with MS (MSG, n = 19) and a control group (CG, n = 17). R-R intervals (RRi) and heart rate variability (HRV) were calculated on a beat-to-beat basis and the heart rate (HR) at the on- and off-transient were analyzed during an incremental cardiopulmonary exercise test (CPET).

Results: MSG showed lower aerobic capacity and lower parasympathetic cardiac modulation at rest compared with CG. HR values in on-transient phase were significantly lower in MSG compared with CG. The exponential amplitudes “amp” and the parameters “τ” [speed of heart rate recovery (HRR)] were lower in MSG. MSG exhibited higher HR values in comparison to CG during the off-transient indicating a slower HRR. In MSG, there was an inverse and significant correlation between fasting plasma vs. ΔF and glucose vs. exponential “τ” of HRR dynamics.

Conclusion: MS is associated with poor heart rate kinetics. The altered HR kinetics seems to be related to alterations in cardiac parasympathetic modulation, and glucose metabolism seems to be the major determinant.

Subjective Responses to Interval and Continuous Exercise in Adults With Exercise-Induced Bronchoconstriction

BACKGROUND

Exercise triggers asthma symptoms among adults with exercise induced bronchoconstriction (EIBC). This may lead to lower physical activity levels among this population. The purpose of this study was to assess perceived exertion (RPE), perceived breathlessness (RPD), affect (FS), and physical activity enjoyment during and following an acute bout of high intensity interval exercise (HIIE), moderate intensity interval (MIIE) and moderate intensity continuous exercise (MICE) in adults with EIBC.

METHODS

RPD, RPE, and FS were assessed each minute during the sessions and enjoyment was assessed following each session (n = 11).

RESULTS

RPE was lower during MIIE compared with MICE (P = .006). RPD was lowest during MIIE but was not different between HIIE and MICE. Affect was lower in MICE than HIIE in the last minute of exercise (P = .003) and overall was greatest during the MIIE (P = .022; P = .018). Enjoyment scores were similar between protocols.

CONCLUSIONS

Interval exercise is associated with lower ratings of perceived exertion and dyspnea, an increase in in-task affect, and similar physical activity enjoyment when compared with continuous exercise.

Acute effects of different types of aerobic exercise on endothelial function and arterial stiffness

BACKGROUND

Chronic aerobic exercise training is associated with improved endothelial function and arterial stiffness and favourable long-term cardiovascular effects.

DESIGN

We investigated the acute effects of continuous moderate intensity aerobic exercise (CAE) and high intensity interval aerobic exercise (hIAE) on endothelial function and arterial stiffness in healthy participants.

METHODS

Twenty healthy men were recruited to this cross-over study. They participated in two exercise sessions: (a) CAE, volume at 50% of maximum aerobic work for 30 minutes; and (b) hIAE, interval maximum aerobic work for 30 minutes. Endothelial function was evaluated by flow-mediated dilation in the brachial artery. The carotid femoral pulse wave velocity and the femoral dorsalis pedis pulse wave velocity were measured as indices of central aortic and peripheral arterial stiffness. Measurements were carried out before and immediately after each exercise session.

RESULTS

There was no statistically significant difference in the baseline measurements before CAE and hIAE with respect to flow-mediated dilation, the carotid femoral pulse wave velocity and the femoral dorsalis pedis pulse wave velocity (p = NS). Both CAE and hIAE significantly improved the flow-mediated dilation compared with baseline (p < 0.001). Similarly, the femoral dorsalis pedis pulse wave velocity was improved after CAE and hIAE (p < 0.005), whereas the carotid femoral pulse wave velocity was not significantly affected (p = NS).

CONCLUSION

Both CAE and hIAE can favourably affect endothelial function, suggesting another cardioprotective effect of acute exercise. These types of aerobic exercise have a different impact on the central and peripheral arterial stiffness.

Similar Responses of Circulating MicroRNAs to Acute High-Intensity Interval Exercise and Vigorous-Intensity Continuous Exercise

High-intensity interval exercise (HIIE) has been reported to be more beneficial for physical adaptation than low-to-moderate exercise intensity. Recently, it is becoming increasingly evident that circulating miRNAs (c-miRNAs) may distinguish between specific stress signals imposed by variations in the duration, modality, and type of exercise. The aim of this study is to investigate whether or not HIIE is superior to vigorous-intensity continuous exercise (VICE), which is contributing to develop effective fitness assessment. Twenty-six young males were enrolled, and plasma samples were collected prior to exercise and immediately after HIIE or distance-matched VICE. The miRNA level profiles in HIIE were initially determined using TaqMan Low Density Array (TLDA). And the differentially miRNAs levels were validated by stem-loop quantitative reverse-transcription PCR (RT-qPCR). Furthermore, these selective c-miRNAs were measured for VICE. Our results showed that some muscle-related miRNAs levels in the plasma, such as miR-1, miR-133a, miR-133b, and miR-206 significantly increased following HIIE or VICE compared to those at rest (P < 0.05), and there was only a significant reduction in miR-1 level for HIIE compared to VICE (P < 0.05), while no significant differences were observed for other muscle-related miRNAs between both exercises (P > 0.05). In addition, some tissue-related or unknown original miRNA levels, such as miR-485-5p, miR-509-5p, miR-517a, miR-518f, miR-520f, miR-522, miR-553, and miR-888, also significantly increased (P < 0.05) in both exercises compared to rest. However, no significant differences were found between both exercises (P > 0.05). Overall, endurance exercise assessed in this study both led to significant increases in selective c-miRNAs of comparable magnitude, suggesting that both types of endurance exercise have general stress processes. Accordingly, the similar responses to both acute exercises likely indicate both exercises can be used interchangeably. Further work is needed to reveal the functional significance and signaling mechanisms behind changes in c-miRNA turnover during exercise.