Prevalence and predictors of dropout from high-intensity interval training in sedentary individuals: A meta-analysis

The Effects of High-Intensity Interval Training and Moderate Alcohol Consumption on Cognitive Performance-A Multidisciplinary Intervention in Young Healthy Adults

BACKGROUND

The main purpose of this study was to determine the effects of a high-intensity interval training (HIIT) intervention in the context of moderate alcohol consumption on cognitive performance in healthy young adults.

METHODS

We conducted a 10-week HIIT program along with four types of beverages with/without alcohol content. A total of 75 healthy adults (18-40 years old; 46% female) were allocated to either a control Non-Training group or an HIIT program group (2 days/week). Using block randomization, participants in the HIIT group were further allocated to an HIIT-Alcohol group (alcohol beer or sparkling water with vodka added, 5.4%) or an HIIT-NonAlcohol group (sparkling water or non-alcohol beer, 0.0%). The control group was instructed to maintain an active lifestyle but did not undergo any regular training. A comprehensive neuropsychological battery was used to evaluate cognitive performance (i.e., memory, working memory, processing speed, inhibitory control, and verbal fluency). Changes from baseline to week 10 were included in the main analyses.

RESULTS

All groups improved in all neuropsychological measures (all p ≤ 0.001), independent of sex and alcohol consumption, with no statistical differences between groups (all p > 0.05). Furthermore, larger increases in maximal oxygen uptake were associated with greater improvements in processing speed, inhibitory control, and verbal fluency (all p < 0.050).

CONCLUSIONS

Although the improvements found in cognitive performance cannot be attributed to the HIIT intervention, no significant impairments in cognitive functions were noted due to moderate alcohol intake. Furthermore, our results confirmed that exercise-induced physical fitness improvements were associated with cognitive performance enhancements in young healthy adults.

Effect of High-Intensity Interval, Moderate-Intensity Continuous, and Self-Selected Intensity Training on Health and Affective Responses

Purpose: To compare the effects of 12-week high-intensity interval (HIIT), moderate-intensity continuous (MICT), and self-selected intensity training (SSIT) on health outcomes and affective responses. Methods: Seventy-three overweight/obese inactive adults (62% woman; age, 31.4 ± 7.2 years; height, 1.66 ± 0.09 cm; Body mass index, 28.9 ± 2.7 kg.m-2) who were randomized into HIIT (n = 23), MICT (n = 24) and SSIT (n = 26) groups. The training was conducted three times per week in an outdoor environment, with 4 weeks under direct supervision and 8 weeks with semi-supervision. Cardiorespiratory fitness, body composition, and metabolic profile were evaluated at baseline and at the end of the 4th and 12th weeks. Core affect was measured during all training sessions. Results: Peak oxygen uptake improved in all groups after 4 and 12 weeks compared with baseline. Only the SSIT had reductions in body fat throughout the intervention. No improvements were observed in the metabolic profile across all groups. SSIT was perceived as more pleasurable than HIIT; however, there were no differences in affective responses between SSIT and MICT. Affective responses in-task (e.g. negative and positive peak, rate of change and affect at the end of the exercise session) predicted the HIIT and SSIT exercises attendance rate. Conclusion: Regardless of the exercise training protocol, overweight/obese inactive adults improved health outcomes, which suggests the prescribing HIIT, MICT, and SSIT in outdoor environments. SSIT should be considered in order to optimize the pleasure during training sessions. Affective response more positive in-task of the HIIT and SSIT is associated with greater attendance rate in these exercise protocols.

Is low-volume high-intensity interval training a time-efficient strategy to improve cardiometabolic health and body composition? A meta-analysis

The present meta-analysis aimed to assess the effects of low-volume high-intensity interval training (LV-HIIT; i.e., ≤5 min high-intensity exercise within a ≤15 min session) on cardiometabolic health and body composition. A systematic search was performed in accordance with PRISMA guidelines to assess the effect of LV-HIIT on cardiometabolic health and body composition. Twenty-one studies (moderate to high quality) with a total of 849 participants were included in this meta-analysis. LV-HIIT increased cardiorespiratory fitness (CRF, SMD = 1.19 [0.87, 1.50]) while lowering systolic blood pressure (SMD = -1.44 [-1.68, -1.20]), diastolic blood pressure (SMD = -1.51 [-1.75, -1.27]), mean arterial pressure (SMD = -1.55 [-1.80, -1.30]), MetS z-score (SMD = -0.76 [-1.02, -0.49]), fat mass (kg) (SMD = -0.22 [-0.44, 0.00]), fat mass (%) (SMD = -0.22 [-0.41, -0.02]), and waist circumference (SMD = -0.53 [-0.75, -0.31]) compared to untrained control (CONTROL). Despite a total time-commitment of LV-HIIT of only 14%-47% and 45%-94% compared to moderate-intensity continuous training and HV-HIIT, respectively, there were no statistically significant differences observed for any outcomes in comparisons between LV-HIIT and moderate-intensity continuous training (MICT) or high-volume HIIT. Significant inverse dose-responses were observed between the change in CRF with LV-HIIT and sprint repetitions (β = -0.52 [-0.76, -0.28]), high-intensity duration (β = -0.21 [-0.39, -0.02]), and total duration (β = -0.19 [-0.36, -0.02]), while higher intensity significantly improved CRF gains. LV-HIIT can improve cardiometabolic health and body composition and represent a time-efficient alternative to MICT and HV-HIIT. Performing LV-HIIT at a higher intensity drives higher CRF gains. More repetitions, longer time at high intensity, and total session duration did not augment gains in CRF.

Cardiorespiratory Fitness and Performance Adaptations to High-Intensity Interval Training: Are There Differences Between Men and Women? A Systematic Review with Meta-Analyses

BACKGROUND

It is important to consider biological sex as a variable that might influence exercise adaptation in order to optimize exercise prescription for men and women.

OBJECTIVE

The aim of this study was to quantify the impact of biological sex on maximal oxygen uptake ([Formula: see text]O2max) and performance outcomes after high-intensity interval training (HIIT).

METHODS

A systematic search and review was conducted by two independent reviewers up to 8 September 2022 using MEDLINE, SPORTDiscus, and Sports Medicine & Education Index in ProQuest. Trials including healthy adults were included if they presented data for or compared male and female [Formula: see text]O2max or performance outcomes in response to HIIT. Performance outcomes included measures of exercise performance and concurrently measured physiological adaptations. Where appropriate, a random-effects, pre-post meta-analysis was undertaken. Data were sub-grouped for men and women, baseline training level, mean age, intervention type, and intervention length. Heterogeneity was assessed using Chi2, Cochran's Q, and Higgins I2 and sensitivity analyses, where required. Study quality was assessed using the Newcastle-Ottawa Scale and publication bias was assessed through visual inspection of funnel plots.

RESULTS

Thirty-three references from 28 trials were included in the review (n = 965; 462 women and 503 men). Meta-analyses included 19 studies for [Formula: see text]O2max, eight for peak power output from [Formula: see text]O2max testing (PPO), and five for threshold power (powerAT). Meta-analyses revealed similar increases in [Formula: see text]O2max in women (g = 0.57; 95% CI 0.44-0.69) and men (g = 0.57; 95% CI 0.42-0.72), and powerAT in women (g = 0.38; 95% CI 0.13-0.64) and men (g = 0.38; 95% CI 0.11-0.64). Raw mean differences for change in [Formula: see text]O2max were Δ 0.32 L·min-1 and 3.50 mL·kg-1·min-1 in men, versus Δ 0.20 L·min-1 and 3.34 mL·kg-1·min-1 for women. No significant sex differences were present for the primary analysis of any outcome. After sub-grouping, significant differences were present for PPO where the effect size was higher for well-trained women (g = 0.37) compared with well-trained men (g = 0.17), and for [Formula: see text]O2max where interventions with a duration of 4 weeks or less had significantly smaller effect sizes compared with those longer than 4 weeks (p < 0.001). Unweighted mean percentage change in [Formula: see text]O2max, PPO, and powerAT across studies was 11.16 ± 7.39%, 11.16 ± 5.99%, and 8.07 ± 6.55% for women, and 10.90 ± 5.75%, 8.22 ± 5.09%, and 7.09 ± 7.17% for men, respectively. Significant heterogeneity was present for both [Formula: see text]O2max and PPO (I2, range: 62.06-78.80%). Sub-grouping by baseline training status and intervention length decreased heterogeneity in most groups. A qualitative synthesis of other outcomes indicated similar improvements in fitness and performance for men and women with some evidence suggesting differences in the mechanisms of adaptation.

LIMITATIONS AND RISK OF BIAS

Publication bias is unlikely to have significantly influenced results for [Formula: see text]O2max or powerAT, but the meta-analysis of PPO could have benefitted from additional study data to strengthen results. The overlap in age categories and sensitivity of the analysis limits the accuracy of the results of the sub-grouping by age.

CONCLUSIONS

Findings indicated no sex-specific differences for any fitness or performance outcomes. Baseline training status and intervention length accounted for most variability in outcomes. PROSPERO registration number: CRD42021272615.

Effects of 10-Week Online Moderate- to High-Intensity Interval Training on Body Composition, and Aerobic and Anaerobic Performance during the COVID-19 Lockdown

The present study aimed to investigate the effects of a 10-week online high-intensity interval training (HIIT) program on body composition and aerobic and aerobic performance in physically sedentary women. A parallel, two-group, longitudinal (pre, post) design was used with physical tests performed before (preintervention) and after (postintervention) the 10-week intervention period. A total of forty-eight healthy and physically sedentary women (defined as an individual who lacks regular exercise or a structured fitness routine) were recruited to participate in this study. The participants were distributed in two groups: the experimental group (EG) with 24 women (mean ± SD: age 21.21 ± 2.15 years; weight: 61.16 ± 8.94 kg; height: 163.96 ± 4.87 cm; body mass index (BMI): 22.69 ± 2.49 kg/m2) and the control group (CG) with another 24 women (mean ± SD: age 20.50 ± 1.29 years; weight: 62.0 ± 6.65 kg; height: 163.92 ± 4.89 cm; body mass index: 23.04 ± 1.74 kg/m2). The EG performed an online HIIT program for 10 weeks, while the CG continued with their daily life routines. The repeated measures ANCOVA indicated a significant effect in the within-group analysis for weight (p = 0.001; d = -0.96) and for BMI (p = 0.001; d = 0.24), with a significant decrease in the experimental group (EG). The control group (CG) did not show any significant decrease in either body weight or BMI. Regarding the maximal oxygen uptake (VO2 max) values, the EG exhibited a significant improvement (p = 0.001; d = -1.07), whereas the CG did not demonstrate a significant improvement (p = 0.08; d = -0.37). The EG's power output (W) (p = 0.001; d = -0.50) and power output standardized by body weight (W/kg) (p = 0.001; d = -0.96) were significantly improved. The CG did not show a significant improvement in either power output (W/kg) or power output. Lastly, the within-group analysis with load revealed that the EG significantly improved (p = 0.001; d = -0.50), while CG did not show a significant improvement in load (p = 0.10.; d = -0.10). The present study showed that 10 weeks of HIIT in an online environment during the COVID-19 lockdown significantly improved maximum oxygen consumption and caused weight loss and a significant decrease in body mass index in physically sedentary women. These results suggest that HIIT may be used as a time-efficient strategy to improve body composition and cardio-respiratory fitness in sedentary women.

Effect of acute and long-term exercise on leptin levels in depressed outpatients

BACKGROUND

Depression is a leading cause of disability worldwide and a significant contributor to the global burden of disease. Altered leptin levels are known to be associated with depressive symptoms, however discrepancies in the results of increased or decreased levels exist. Due to various limitations associated with commonly used antidepressant drugs, alternatives such as exercise therapy are gaining more importance. Therefore, the current study investigates whether depressed patients have higher leptin levels compared to healthy controls and if exercise is efficient to reduce these levels.

METHODS

Leptin levels of 105 participants with major depressive disorder (MDD; 45.7% female, age mean ± SEM: 39.1 ± 1.0) and 34 healthy controls (HC; 61.8% female, age mean ± SEM: 36.0 ± 2.0) were measured before and after a bicycle ergometer test. Additionally, the MDD group was separated into three groups: two endurance exercise intervention groups (EX) differing in their intensities, and a waiting list control group (WL). Leptin levels were measured pre and post a 12-week exercise intervention or the waiting period.

RESULTS

Baseline data showed no significant differences in leptin levels between the MDD and HC groups. As expected, correlation analyses displayed significant relations between leptin levels and body weight (HC: r = 0.474, p = 0.005; MDD: r = 0.198, p = 0.043) and even more with body fat content (HC: r = 0.755, p < 0.001; MDD: r = 0.675, p < 0.001). The acute effect of the bicycle ergometer test and the 12-week training intervention showed no significant changes in circulating leptin levels.

CONCLUSION

Leptin levels were not altered in patients with major depression compared to healthy controls and exercise, both the acute response and after 12 weeks of endurance training, had no effect on the change in leptin levels.

TRIAL REGISTRATION

The study was registered at the German register for clinical studies (DRKS) and the International Clinical Trials Registry Platform of the World Health Organization https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS00008869 on 28/07/2015.

Effects of the menstrual cycle on EPOC and fat oxidation after low-volume high-intensity interval training

BACKGROUND

Low-volume high-intensity interval training (HIIT) for weight loss has become prevalent in recent years, with increased excess post-exercise oxygen consumption (EPOC) as the mechanism. However, the influence of the menstrual cycle on EPOC and fat oxidation following low-volume HIIT is unclear. This study aimed to investigate the effect of the menstrual cycle on the increase in EPOC and fat oxidation after low-volume HIIT.

METHODS

Twelve eumenorrheic women participated during their early follicular and luteal phases. On each experimental day, they performed low-volume HIIT comprising fifteen repeated 8 s sprint cycling tests with 12 s rests, for 5 min. Expired gas samples were collected before and every 60 min until 180 min post-exercise. EPOC was defined as the increase in oxygen consumption from the resting state, and the total EPOC and fat oxidation were calculated from the total time of each measurement. Blood samples for serum estradiol, progesterone, free fatty acids, blood glucose, lactate, and plasma noradrenaline were collected and assessed before immediately after, and at 180 min post-exercise and were assessed.

RESULTS

Serum estradiol and progesterone were significantly higher in the luteal phase than the follicular phase (P<0.01 for both). No significant differences in total EPOC and fat oxidation were found between the menstrual phases. Serum free fatty acid, blood glucose, lactate, and plasma noradrenaline concentrations were not affected by the menstrual cycle.

CONCLUSIONS

These results suggest that the menstrual cycle does not affect the increase in EPOC or fat oxidation after low-volume HIIT.

Differential Effects of Very-Low-Volume Exercise Modalities on Telomere Length, Inflammation, and Cardiometabolic Health in Obese Metabolic Syndrome Patients: A Subanalysis from Two Randomized Controlled Trials

Oxidative stress (OS) and inflammation are features of metabolic syndrome (MetS) that can contribute to the shortening of telomere length (TL), a marker of cellular ageing. Research indicates that exercise can positively influence MetS-associated conditions and TL. However, the effects of low-volume exercise types on TL are still unknown. We investigated the impact of very-low-volume high-intensity interval training (LV-HIIT), one-set resistance training (1-RT), and whole-body electromyostimulation (WB-EMS) on TL, inflammation, and cardiometabolic indices in 167 MetS patients. Data were derived from two randomized controlled trials where patients were allocated to an exercise group (2 sessions/week, for 12 weeks) or a control group. All groups received standard-care nutritional weight loss counselling. TL was determined as the T/S ratio (telomere to single-copy gene amount). All groups significantly reduced body weight (p < 0.05), but the T/S-ratio (p < 0.001) only increased with LV-HIIT. OS-related inflammatory markers (C-reactive protein, interleukin-6, and lipopolysaccharide-binding protein) only decreased (p < 0.05) following LV-HIIT. The MetS severity z-score improved with LV-HIIT (p < 0.001) and 1-RT (p = 0.014) but not with WB-EMS. In conclusion, very-low-volume exercise modalities have differential effects on telomeres, inflammation, and cardiometabolic health. Only LV-HIIT but not strength-based low-volume exercise increased TL in MetS patients, presumably due to superior effects on OS-related inflammatory markers.

Proteolytic markers associated with a gain and loss of leg muscle mass with resistance training followed by high-intensity interval training

We recently reported that vastus lateralis (VL) cross-sectional area (CSA) increases after 7 weeks of resistance training (RT, 2 days/week), with declines occurring following 7 weeks of subsequent treadmill high-intensity interval training (HIIT) (3 days/week). Herein, we examined the effects of this training paradigm on skeletal muscle proteolytic markers. VL biopsies were obtained from 11 untrained college-aged males at baseline (PRE), after 7 weeks of RT (MID), and after 7 weeks of HIIT (POST). Tissues were analysed for proteolysis markers, and in vitro experiments were performed to provide additional insights. Atrogene mRNAs (TRIM63, FBXO32, FOXO3A) were upregulated at POST versus both PRE and MID (P < 0.05). 20S proteasome core protein abundance increased at POST versus PRE (P = 0.031) and MID (P = 0.049). 20S proteasome activity, and protein levels for calpain-2 and Beclin-1 increased at MID and POST versus PRE (P < 0.05). Ubiquitinated proteins showed model significance (P = 0.019) with non-significant increases at MID and POST (P > 0.05). in vitro experiments recapitulated the training phenotype when stimulated with a hypertrophic stimulus (insulin-like growth factor 1; IGF1) followed by a subsequent AMP-activated protein kinase activator (5-aminoimidazole-4-carboxamide ribonucleotide; AICAR), as demonstrated by larger myotube diameter in IGF1-treated cells versus IGF1 followed by AICAR treatments (I+A; P = 0.017). Muscle protein synthesis (MPS) levels were also greater in IGF1-treated versus I+A myotubes (P < 0.001). In summary, the loss in RT-induced VL CSA with HIIT coincided with increases in several proteolytic markers, and sustained proteolysis may have driven this response. Moreover, while not measured in humans, we interpret our in vitro data to suggest that (unlike RT) HIIT does not stimulate MPS. NEW FINDINGS: What is the central question of this study? Determining if HIIT-induced reductions in muscle hypertrophy following a period of resistance training coincided with increases in proteolytic markers. What is the main finding and its importance? Several proteolytic markers were elevated during the HIIT training period implying that increases in muscle proteolysis may have played a role in HIIT-induced reductions in muscle hypertrophy.

Effects of Controlled Supramaximal High-Intensity Interval Training on Cardiorespiratory Fitness and Global Cognitive Function in Older Adults: The Umeå HIT Study-A Randomized Controlled Trial

BACKGROUND

This study examined the effects of regulated and controlled supramaximal high-intensity interval training (HIT) adapted for older adults, compared to moderate-intensity training (MIT), on cardiorespiratory fitness; cognitive, cardiovascular, and muscular function; and quality of life.

METHODS

Sixty-eight nonexercising older adults (66-79 years, 44% males) were randomized to 3 months of twice-weekly HIT (20-minute session including 10 × 6-second intervals) or MIT (40-minute session including 3 × 8-minute intervals) on stationary bicycles in an ordinary gym setting. Individualized target intensity was watt controlled with a standardized pedaling cadence and individual adjustment of the resistance load. Primary outcomes were cardiorespiratory fitness (V̇o2peak) and global cognitive function (unit-weighted composite).

RESULTS

V̇o2peak increased significantly (mean 1.38 mL/kg/min, 95% CI [0.77, 1.98]), with no between-group difference (mean difference 0.05 [-1.17, 1.25]). Global cognition did not improve (0.02 [-0.05, 0.09]), nor differed between groups (0.11 [-0.03, 0.24]). Significant between-group differences in change were observed for working memory (0.32 [0.01, 0.64]), and maximal isometric knee extensor muscle strength (0.07 N·m/kg [0.003, 0.137]), both in favor of HIT. Irrespective of the group, there was a negative change in episodic memory (-0.15 [-0.28, -0.02]), a positive change in visuospatial ability (0.26 [0.08, 0.44]), and a decrease in systolic (-2.09 mmHg [-3.54, -0.64]) and diastolic (-1.27 mmHg [-2.31, -0.25]) blood pressure.

CONCLUSIONS

In nonexercising older adults, 3 months of watt-controlled supramaximal HIT improved cardiorespiratory fitness and cardiovascular function to a similar extent as MIT, despite half the training time. In favor of HIT, there was an improvement in muscular function and a potential domain-specific effect on working memory.

CLINICAL TRIAL REGISTRATION

NCT03765385.

Elucidating the primary mechanisms of high-intensity interval training for improved cardiac fitness in obesity

Obesity is a global and rising multifactorial pandemic associated with the emergence of several comorbidities that are risk factors for malignant cardiac remodeling and disease. High-intensity interval training (HIIT) has gained considerable attention due to its favorable outcomes of cardiometabolic health in individuals with overweight or obese. The primary aim of this review is to discuss the fundamental processes through which HIIT improves cardiac impairment in individuals with obesity to develop viable treatments for obesity management. In this review, a multiple database search and collection were conducted from the earliest record to January 2013 for studies included the qualitative component of HIIT intervention in humans and animals with overweight/obesity related to cardiac remodeling and fitness. We attempt to integrate the main mechanisms of HIIT in cardiac remolding improvement in obesity into an overall sequential hypothesis. This work focus on the ameliorative effects of HIIT on obesity-induced cardiac remodeling with respect to potential and pleiotropic mechanisms, including adipose distribution, energy metabolism, inflammatory response, insulin resistance, and related risk profiles in obesity. In conclusion, HIIT has been shown to reduce obesity-induced risks of cardiac remodeling, but the long-term effects of HIIT on obesity-induced cardiac injury and disease are presently unknown. Collective understanding highlights numerous specific research that are needed before the safety and effectiveness of HIIT can be confirmed and widely adopted in patient with obesity.

Intermittent high-intensity exercise for pre- to established hypertension: A systematic review and meta-analysis

OBJECTIVE

To determine the impact of intermittent high-intensity exercise training ([IHIE], including high-intensity interval training [HIIT] and recreational team sports [RTS]) on systolic (SBP) and diastolic blood pressure (DBP) in adults with pre- to established arterial hypertension.

DATA SOURCES

MEDLINE, Cochrane Library, Embase, and SPORTDiscus.

ELIGIBILITY CRITERIA

Randomized controlled trials (RCTs) comparing the impact of IHIE on BP versus a non-exercise control.

DATA COLLECTION AND ANALYSIS

Two authors independently conducted all procedures. Mean differences were calculated using random-effects model. The certainty of the evidence was assessed with GRADE.

RESULTS

Twenty-seven RCTs (18 HIIT and 9 RTS) were analyzed, with median duration of 12 weeks. Participants' (n = 946) median age was 46 years. Overall, IHIE decreased SBP (-3.29 mmHg; 95% CI: -5.19, -1.39) and DBP (-2.62 mmHg; 95% CI: -3.79, -1.44) compared to the control group. IHIE elicited higher decreases in office SBP and DBP of hypertensive subjects (SBP: -7.13 mmHg, [95% CI: -10.12, -4.15]; DBP: -5.81 mmHg, [95% CI: -7.94, -3.69]) than pre-hypertensive (SBP: -2.14 mmHg, [95% CI: -4.36, -0.08]; DBP: -1.83 mmHg, [95% CI: -2.99, -0.67]). No significant differences were found between HIIT (SBP: -2.12 mmHg, [95% CI: -4.78, -0.54]; DBP: -1.89 mmHg, [95% CI: -3.32, -0.48]) and RTS (SBP: -4.18 mmHg, [95% CI: -7.19, -2.43]; DBP: -4.04 mmHg, [95% CI: -6.00, -2.09]). These findings present low/very low certainty of evidence. No adverse cardiovascular events were reported.

CONCLUSIONS

IHIE appears to be safe and to promote substantial decreases in BP, particularly in patients with hypertension. However, the certainty of evidence was low/very low.

PROTOCOL

CRD42020163575.

Dough kneading exposure at the kitchen workstation: Influence on handgrip strength and implications for therapy in hand rehabilitation

BACKGROUND

Dough kneading is a commonly performed activity in the kitchen, which influences hand grip strength.

OBJECTIVES

To study the influence of dough kneading exposure on hand grip strength and to evaluate the effect of dough kneading intervention on hand grip strength with the purpose of recommending dough kneading as a therapeutic exercise for improving hand grip strength.

METHODS

One hundred and fifty healthy females with varying levels of exposure to dough kneading, stratified as occupational dough kneaders, habitual dough kneaders and non-kneaders, were studied. Hand grip strength of all participants was measured with a standard protocol using the Jamar dynamometer. Hand grip strength of occupational, habitual and non-kneaders was compared. Non-kneaders followed a 6-week intervention of dough kneading and grip strength was recorded post-intervention.

RESULT

Comparison of hand grip strength between the three groups revealed significant difference (p value < 0.001). Linear contrast analysis, revealed the least hand grip strength in non-kneaders compared to habitual and occupational dough kneaders, with occupational dough kneaders presenting maximum hand grip strength (p value < 0.001). Significant improvement was demonstrated in hand grip strength post-intervention in non-kneaders (p value < 0.001).

CONCLUSION

Findings suggest that exposure to dough kneading has a positive influence on hand grip strength. Hand grip strength of non-kneaders was lowest compared to habitual and occupational kneaders. Kneading intervention improved hand grip strength and hence can be used therapeutically as a safe, low cost exercise in hand rehabilitation.

Physical exercise training as preceding treatment to cognitive behavioral therapy in mild to moderate major depressive disorder: A randomized controlled trial

BACKGROUND

Many patients with major depressive disorder (MDD) remain untreated or do not respond to cognitive behavioral therapy (CBT). Physical exercise shows antidepressive effects and may serve as an effective augmentation treatment. However, research on combining exercise with CBT is sparse in MDD and underlying mechanisms of exercise are not well understood to date.

METHODS

120 outpatients with MDD were randomized to either a high intensity exercise group (HEX), a low intensity exercise group (LEX), or a waiting list control group (WL). After 12 weeks of exercise training or waiting period, all patients received a manualized CBT.

RESULTS

Seventy-five patients with MDD completed both the exercise program/ waiting period and the CBT. While physical fitness improved in HEX after the exercise program, it did not change in LEX and WL. Depressive symptoms improved in all three groups from baseline to post-CBT and the group by time interaction was not significant. Regression analyses revealed that the amount of fitness improvement during exercise predicted the subsequent CBT response.

LIMITATIONS

The dropout rate was relatively high, preparatory CBT sessions during exercise / waiting period may have influenced depressive symptoms, and no patients with severe MDD were included.

CONCLUSIONS

High intense physical exercise did not lead to a general enhancement of CBT outcome, but higher increases in physical fitness seem to improve symptom change during CBT. Our results suggest that the implementation of more individually tailored exercise programs could be a promising approach for future research and clinical practice.

Effectiveness of HIIT in patients with cancer or cancer survivors: An umbrella and mapping review with meta-meta-analysis

OBJECTIVE

To assess the available evidence on the effectiveness of high-intensity interval training (HIIT) in addition to first-choice cancer treatment on cardiorespiratory fitness (CRF), quality of life (QoL), adherence, and adverse effects of HIIT in patients with cancer or cancer survivors.

METHODS

An umbrella review and meta-meta-analysis (MMA) was performed. A systematic search was conducted in MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science until August 2021. Article selection, quality assessment, and risk of bias assessment were performed by two independent reviewers. The MMA were performed with a random-effects model and the summary statistics were presented in the form of forest plot with a weighted compilation of all standardized mean differences (SMD) and corresponding 95% confidence interval (CI).

RESULTS

Seven systematic reviews were included. Regarding CRF, the addition of HIIT to cancer treatment showed statistically significant differences with a small clinical effect, compared with adding other treatments (SMD = 0.45; 95% CI 0.24 to 0.65). There was no significant difference when compared with adding moderate-intensity continuous training (MICT) (SMD = 0.23; 95% CI -0.04 to 0.50). QoL showed positive results although with some controversy. Adherence to HIIT intervention was high, ranging from 54% to 100%. Regarding adverse effects, most of the systematic reviews reported none, and in the cases in which they occurred, they were mild.

CONCLUSION

In conjunction with first-choice cancer treatment, HIIT has been shown to be an effective intervention in terms of CRF and QoL, as well as having optimal adherence rate. In addition, the implementation of HIIT in patients with cancer or cancer survivors is safe as it showed no or few adverse effects.

Feasibility, Safety, and Preliminary Efficacy of Very Low-Volume Interval Training in Advanced Cancer Patients

PURPOSE

High-intensity interval training (HIIT) has been shown to improve cardiorespiratory fitness (CRF) and health-related outcomes in various chronic diseases, including cancer. However, data on feasibility and efficacy of HIIT in advanced cancer patients are still sparse, presumably because of safety concerns, like suspected immunosuppression after vigorous exercise. This randomized, sham-intervention controlled study aimed to investigate feasibility, safety, and preliminary efficacy of very low-volume HIIT (LOW-HIIT) in advanced cancer patients.

METHODS

Twenty-seven patients (55.4 ± 13.2 yr) with different advanced cancers (Union for International Cancer Control [UICC] III/IV) were randomly allocated to LOW-HIIT ( n = 13), consisting of 5 × 1 min cycle ergometer intervals (14 min per session total duration) at 80% to 95% HR peak (two sessions per week for 12 wk), or a sham intervention ( n = 14) performing light physical mobilization exercises (SHAM). Primary outcomes were attrition and attendance rates, with values of ≤25% and ≥80%, respectively, considered acceptable. Secondary outcomes were safety, protocol fidelity, physiological (including CRF measures) and patient-reported outcomes (including fatigue and quality of life).

RESULTS

One of 13 patients (8%) receiving LOW-HIIT dropped out. Mean attendance rate was ~93%. The prescribed minimum exercise intensity was consistently reached by all patients. Low-volume HIIT was well tolerated and not associated with any serious adverse event nor with increased infection susceptibility. There were no biochemical signs of acute immunosuppression after LOW-HIIT. Contrarily, differentiation and degranulation of natural killer cells was acutely increased postexercise. Low-volume HIIT improved CRF measures including peak oxygen uptake, self-reported fatigue, physical, and social functioning. No significant changes occurred in the SHAM group.

CONCLUSIONS

Low-volume HIIT can be regarded as feasible and safe in advanced cancer patients. Our preliminary data indicate favorable acute effects on NK-cells and beneficial chronic adaptations in CRF, fatigue, and aspects of quality of life.

Very Low-Volume, High-Intensity Interval Training Mitigates Negative Health Impacts of COVID-19 Pandemic-Induced Physical Inactivity

Initially, we aimed to investigate the impact of a one-year worksite low-volume, high-intensity interval training (LOW-HIIT) on cardiometabolic health in 114 sedentary office workers. Due to the COVID-19 pandemic outbreak, LOW-HIIT was discontinued after 6 months and participants were followed up for 6 months to analyze physical activity/exercise behavior and outcome changes during lockdown. Health examinations, including cardiopulmonary exercise testing and the assessment of cardiometabolic markers were performed baseline (T-1), after 6 months (T-2, termination of worksite LOW-HIIT) and 12 months (T-3, follow-up). Cycle ergometer LOW-HIIT (5 × 1 min at 85-95% HR_max) was performed 2×/week. For follow-up analyses, participants were classified into three groups: HIIT-group (continued home-based LOW-HIIT), EX-group (continued other home-based exercises), and NO-EX-group (discontinued LOW-HIIT/exercise). At T-2, VO_2max (+1.5 mL/kg/min, p = 0.002), mean arterial blood pressure (MAB, -4 mmHg, p < 0.001), HbA_1c (-0.2%, p = 0.005) and self-reported quality of life (QoL, +5 points, p < 0.001) were improved. At T-3, HIIT-group maintained VO_2max and QoL and further improved MAB. EX-group maintained MAB and QoL but experienced a VO_2max decrease. In NON-EX, VO_2max, MAB and QoL deteriorated. We conclude that LOW-HIIT can be considered a promising option to improve cardiometabolic health in real-life conditions and to mitigate physical inactivity-related negative health impacts during lockdowns.

Physical Health Impairment and Exercise as Medicine in Severe Mental Disorders: A Narrative Review

BACKGROUND

Individuals with severe mental disorders (SMDs; schizophrenia spectrum disorders, bipolar disorder, and major depressive disorder) are not only suffering from their mental conditions; they also have an attenuated physical health, augmenting their overall critical condition.

OBJECTIVES

We review and critically appraise the evidence based on (1) key physiological factors relating to aerobic endurance and skeletal muscle strength; (2) implications for physical function and health; and (3) effects of training interventions with different intensities evaluated in individuals with SMDs.

FINDINGS

Reductions in aerobic endurance factors, peak oxygen uptake (VO_2peak) and walking work efficiency, are paralleled by reductions in maximal skeletal muscle strength and power. In turn, the poor aerobic endurance and muscle strength lead to impaired physical function, increased risk of lifestyle-related diseases, and ultimately early death. Exercise has the potential to counteract the attenuated physical health in people with SMDs. While aerobic endurance training is shown to increase VO_2peak due to plasticity of the oxygen transport system, strength training is documented to improve maximal muscle strength, power, and walking work efficiency as a result of adaptations in neuromuscular force developing factors.

CONCLUSIONS

In conclusion, improvements in these key determinants for physical health appear to be achievable in people with SMDs despite many being challenged by motivational difficulties with attending regular exercise and have beneficial implications for physical function during activities of daily living, lifestyle-related diseases, and early death.

Physiological, perceptual and affective responses to high-intensity interval training using two work-matched programs with different bout duration in obese males

Objectives

This study compared physiological, perceptual, and affective responses to high-intensity interval training (HIIT) between two work-matched programs with different bout durations in obese males.

Methods

Sixteen low-to-moderately active obese men completed an eight-week cycling program of supervised HIIT (3 days/week) using either short bouts [48 × 10 s at 100% of peak power output (PPO) with 15 s of recovery (HIIT10)] or long bouts [8 × 60 s at 100% PPO with 90 s of recovery (HIIT60)]. Workload was progressively adjusted, to maintain high intensity (100% PPO), throughout training. Blood lactate (BLa), heart rate (HR), ratings of perceived exertion (RPE), and feeling scale ratings (pleasure/displeasure) were measured in each HIIT session.

Results

Average HR decreased in the last 2 weeks of training in both groups by 2.2 ± 1.8% of peak HR (p < 0.001). Training resulted in a reduction in BLa during exercise by 28 ± 19% (p < 0.001) from the 10th min onward only in HIIT10. Similarly, during the last weeks of training, RPE decreased (by 1.0 ± 1.1 units, p < 0.05) and feeling scale ratings were improved only in HIIT10, while RPE remained unchanged and feeling scale ratings deteriorated in HIIT60 (from 3.0 ± 1.1 to 2.1 ± 0.9 units, p < 0.001). No differences in post-exercise enjoyment were found.

Conclusion

Both HIIT formats induced similar HR adaptations, but improvement of BLa, perceptual and affective responses occurred only when bout duration was shorter. Our findings suggest that, in low-to-moderately active obese men, HIIT may be more effective in improving metabolic, perceptual, and affective responses when shorter, rather than longer, bouts of exercise are used.

Low-Volume Sprint Interval Swimming Is Sufficient to Increase Blood Metabolic Biomarkers in Master Swimmers

Purpose: Sprint interval exercise is a time-efficient way of inducing beneficial adaptations. However, little is known about its minimal effective volume, especially in swimming. The aim of the present study was to evaluate and compare the effects of two sprint interval swimming sets of different low volumes on blood biomarkers. Method: Twenty-one master swimmers [11 females aged 38.5 (8.5) years, 10 males aged 42.7 (5.7) years] completed two freestyle swimming sets of 4 × 50 m and 4 × 25 m at maximal intensity and a work-to-rest ratio of 1:1, on different days, in random and counterbalanced order. Blood samples were taken before, immediately after and one hour after exercise for determination of a number of biochemical parameters. Results: Swimming speed was higher in the 4 × 25-m set. Lactate, glucose, insulin, glucagon, cortisol, and reduced glutathione increased immediately post-exercise, while uric acid increased 1 h post-exercise (p < .05). All aforementioned biomarkers, excluding glucagon, increased more with the 4 × 50-m set, compared to the 4 × 25-m set (p < .05). Session rating of perceived exertion was higher after the 4 × 50-m set (p = .011). Conclusion: Both sprint interval swimming sets elicited increases in blood biomarkers in master swimmers. The set of higher volume elicited greater increases in most of the biochemical markers studied but also in subjective load. Thus, although the set of higher volume was more efficient in perturbing blood biomarkers, even the very low-volume set induced metabolic stress that may trigger adaptive mechanisms.

Impact of High-Intensity Interval Training on Body Composition and Depressive Symptoms in Adults under Home Confinement

The home confinement derived from the COVID-19 pandemic has led to drastic changes in people’s habits. This situation has influenced their eating, rest, physical activity and socialization patterns, triggering changes in their mental stability. It was demonstrated that physical activity is beneficial for people’s physical and mental health. By its moderate volume and requiring little space or material, high-intensity interval training (HIIT) could prove to be a valid alternative in a situation of confinement. The aim of the present study was to observe the impact of an 8-week HIIT protocol on the body composition and the depressive symptoms of adults in strict home confinement. A total of 21 healthy adults, both male and female, (35.4 ± 5.6 years old; 70.50 ± 12.1 kg; 171 ± 10 cm) were divided into an experimental group (EG, n = 11) who carried out an 8-week Tabata protocol, based upon calisthenic exercises with their own weight in their homes, and a control group (CG, n = 10) who did not carry out any systematic physical activity over the same period. Following the intervention, the EG experienced a significant reduction in percentage (t = 3.86, d = 0.57, p < 0.05) and in kg (t = 4.62, d = 0.29, p < 0.05) of body fat mass (BFM) and body fat mass index (BFMI) (t = 4.61, d = 0.31, p < 0.05), as well as a reduction in depressive symptoms (t = 6.48, d = 1.3, p < 0.05). These results indicate that HIIT is a potential public health tool that could possibly be prescribed to the population in case of future situations of home confinement.

Psychological Adaptations to High-Intensity Interval Training in Overweight and Obese Adults: A Topical Review

Regular exercise has been reported as a fundamental piece of the management and treatment puzzle of obesity, playing a vital role in numerous psychological indicators. However, it is unclear whether high-intensity interval training (HIIT) can improve critical psychological health markers such as adherence, exercise enjoyment, affective responses, health-related quality of life, anxiety, and depression in overweight and obese adults. The purpose of this topical review was to catalogue studies investigating the psychological responses to HIIT in order to identify what psychological outcomes have been assessed, the research methods used, and the results. The inclusion/exclusion criteria were met by 25 published articles investigating either a traditional, single-component (84%) or a hybrid-type, multi-component (16%) HIIT protocol and involving 930 participants with overweight/obesity. The present topical review on HIIT-induced psychological adaptations shows that this popular exercise mode, but also demanding for the masses, can meaningfully increase the vast majority of the selected mental health-related indices. These improvements seem to be equal if not greater than those observed for moderate-intensity continuous training in overweight and obese adults. However, further research is needed in this area, focusing on the potential mechanisms behind positive alterations in various psychological health parameters through larger samples and high-quality randomized controlled trials.

Increased Lean Body Mass After Bodyweight-Based High Intensity Interval Training in Overweight and Obese Men

Purpose: The effects of 8 weeks of bodyweight exercise-based, high-intensity interval training (BWHIIT) on body composition and blood-based markers of metabolic health were investigated in overweight and obese, sedentary young men. Methods: In a parallel group, PRE-POST design, n = 30 men (age, 25.7 ± 4.3 y; body mass index, 27.7 ± 2.1 kg m^-2; 26.1 ± 5.2% body fat) were randomized to BWHIIT (n = 20) or a control group (CON; n = 10). BWHIIT consisted of supervised, group-based training sessions (~30 minutes) performed 3 times weekly. Each session consisted of 6 high-intensity bodyweight-based exercises, with each exercise being performed for 4 minutes in the manner of 8 sets of 20 seconds of exercise, 10 seconds of rest. Prior to commencing training (PRE), and 36 h after the final training session (POST), an overnight fasted blood sample was drawn, and body composition was assessed by dual-energy X-ray absorptiometry. Eighteen participants completed the intervention (CON, n = 9; BWHIIT, n = 9). Results: Lean body mass (LBM) was increased at POST in BWHIIT compared to CON (P = .011, η²_p = .359), with the mean (95% confidence limits) increase in LBM from PRE to POST within BWHIIT being 1.23 (0.55, 1.92) kg. Body mass and fat mass were unchanged in both groups from PRE to POST. BWHIIT had no effect on serum concentrations of total cholesterol, HDL-C, LDL-C, triglycerides, NEFA, hsCRP, or glucose. Conclusion: Eight weeks of bodyweight exercise-based high intensity interval training by overweight and obese sedentary young men increased LBM by ~2%, but fat mass and blood-based markers of metabolic health were unchanged.

Effect of Cycle-Based High-Intensity Interval Training and Moderate to Moderate-Intensity Continuous Training in Adolescent Soccer Players

Cardiorespiratory fitness, anaerobic power, and lower extremity strength are essential for soccer players at all levels. An effective program should be developed to improve physical strength for adolescent soccer players who need to combine academic and technical training. This study analyzed the impact of short-term high intensity interval training (HIIT) training and traditional moderate intensity continuous training (MICT) on adolescent soccer players. Participants included 56 adolescent soccer players who were divided into HIIT and MICT groups. The training program was conducted 3 times a week for 4 weeks using cycle ergometer. Each session included the same resistance training program, and the characteristics of HIIT and MICT were applied to improve cardiorespiratory fitness and anaerobic power. Body composition analysis, graded exercise test for peak oxygen uptake (VO₂ peak), Wingate anaerobic power test, and isokinetic knee strength test were performed. VO₂ peak was improved in HIIT and MICT, but anaerobic threshold and heart rate recovery significantly improved in the HIIT group. Wingate anaerobic peak power had increased significantly in sets 1, 2, and 3 in the HIIT group, but showed significant improvement only in set 1 in the MICT group. The isokinetic strength improved significantly in the HIIT group at 60°/s and in the MICT group at 240°/s. There was no significant change in body composition in either group. In conclusion, short-term HIIT administered to adolescent soccer players effectively improved cardiorespiratory fitness in HIIT and MICT groups. While HIIT increased anaerobic threshold and power, MICT effectively improved muscle endurance. Short-term intensive training can be considered a time-efficient training strategy.

Alteration of skeletal and cardiac muscles function in DBA/2J mdx mice background: a focus on high intensity interval training

Duchenne muscular dystrophy (DMD) is a recessive hereditary myopathy due to deficiency of functional dystrophin. Current therapeutic interventions need more investigation to slow down the progression of skeletal and cardiac muscle weakness. In humans, there is a lack of an adapted training program. In animals, the murine Mdx model with a DBA/2J background (D2-mdx) was recently suggested to present pathological features closer to that of humans. In this study, we characterized skeletal and cardiac muscle functions in males and females D2-mdx mice compared to control groups. We also evaluated the impact of high intensity interval training (HIIT) in these muscles in females and males. HIIT was performed 5 times per week during a month on a motorized treadmill. Specific maximal isometric force production and weakness were measured in the tibialis anterior muscle (TA). Sedentary male and female D2-mdx mice produced lower absolute and specific maximal force compared to control mice. Dystrophic mice showed a decline of force generation during repetitive stimulation compared to controls. This reduction was greater for male D2-mdx mice than females. Furthermore, trained D2-mdx males showed an improvement in force generation after the fifth lengthening contraction compared to sedentary D2-mdx males. Moreover, echocardiography measures revealed a decrease in left ventricular end-diastolic volume, left ventricular ejection volume and left ventricular end-diastolic diameter in sedentary male and female D2-mdx mice. Overall, our results showed a serious muscle function alteration in female and male D2-mdx mice compared to controls. HIIT may delay force loss especially in male D2-mdx mice.

Evidence-Based Effects of High-Intensity Interval Training on Exercise Capacity and Health: A Review with Historical Perspective

Engaging in regular exercise results in a range of physiological adaptations offering benefits for exercise capacity and health, independent of age, gender or the presence of chronic diseases. Accumulating evidence shows that lack of time is a major impediment to exercise, causing physical inactivity worldwide. This issue has resulted in momentum for interval training models known to elicit higher enjoyment and induce adaptations similar to or greater than moderate-intensity continuous training, despite a lower total exercise volume. Although there is no universal definition, high-intensity interval exercise is characterized by repeated short bursts of intense activity, performed with a "near maximal" or "all-out" effort corresponding to ≥90% of maximal oxygen uptake or >75% of maximal power, with periods of rest or low-intensity exercise. Research has indicated that high-intensity interval training induces numerous physiological adaptations that improve exercise capacity (maximal oxygen uptake, aerobic endurance, anaerobic capacity etc.) and metabolic health in both clinical and healthy (athletes, active and inactive individuals without any apparent disease or disorder) populations. In this paper, a brief history of high-intensity interval training is presented, based on the novel findings of some selected studies on exercise capacity and health, starting from the early 1920s to date. Further, an overview of the mechanisms underlying the physiological adaptations in response to high-intensity interval training is provided.

Difference in total workload during sprint interval training for adults living with or without obesity

PURPOSE

The primary objective of the study was to compare the implications of body composition on work volume, power outputs (peak, mean, and minimum), and relative drop load throughout 4 weeks of sprint interval training (SIT) in individuals living with and without obesity.

METHODS

Thirty-four participants living with (n = 16) and without (n = 18) obesity took part in 12 sessions of SIT over 4 weeks. SIT consisted of repeated 30-s Wingate with a drop load of 7.5% of the participant's body mass separated by 4 min of active recovery. Fat-free mass was estimated using a BOD POD. Work volume, drop load, and power output (peak, mean, and minimum) relative to body mass and fat-free mass were calculated using a Monark 874E Weight cycle ergometer.

RESULTS

Individuals living with obesity had a significantly larger drop load relative to fat-free mass (p < 0.001) and absolute drop load (p < 0.001) as well as a lower cycling cadence (p < 0.001) compared to individuals without obesity. No significant difference was observed in work volume (p = 0.167) as well as mean (p = 0.903), peak (p = 0.294), and minimum (p = 0.103) power relative to fat-free mass between groups.

CONCLUSION

The findings suggest that individuals living with obesity work at a higher relative drop load when utilizing a percentage of body mass; however, a reduced cycling cadence results in similar total work volume throughout SIT.

Acute effect of HIIT on testosterone and cortisol levels in healthy individuals: A systematic review and meta-analysis

To determine the acute effect of a single high-intensity interval training (HIIT) session on testosterone and cortisol levels in healthy individuals, a systematic search of studies was conducted in MEDLINE and Web of Science databases from inception to February 2020. Meta-analyses were performed to establish the acute effect of HIIT on testosterone and cortisol levels immediately after a single HIIT session; after 30 min and 60 min (primary outcomes); and after 120 min, 180 min, and 24 h (secondary outcomes, only for pre-post intervention groups). Potential effect-size modifiers were assessed by meta-regression analyses and analyses of variance. Study quality was assessed using the Cochrane's risk of bias tool and the Physiotherapy Evidence Database scale. The meta-analyses of 10 controlled studies (213 participants) and 50 pre-post intervention groups (677 participants) revealed a significant increase in testosterone immediately after a single HIIT session (d = 0.92 and 0.52, respectively), which disappeared after 30 min (d = 0.18 and -0.04), and returned to baseline values after 60 min (d = -0.37 and -0.16). Significant increases of cortisol were found immediately after (d = 2.17 and 0.64), after 30 min (d = 1.62 and 0.67) and 60 min (d = 1.32 and 0.27). Testosterone and cortisol levels decreased significantly after 120 min (d = -0.48 and -0.95, respectively) and 180 min (d = -0.29 and -1.08), and returned to baseline values after 24 h (d = 0.14 and -0.02). HIIT components and participant's characteristics seem to moderate the effect sizes. In conclusion, testosterone and cortisol increase immediately after a single HIIT session, then drop below baseline levels, and finally return to baseline values after 24 h. This meta-analysis provides a better understanding of the acute endocrine response to a single HIIT session, which would certainly be valuable for both clinicians and coaches in the prescription of exercise programs to improve health and performance. Testosterone and cortisol may be used as sensitive biomarkers to monitor the anabolic and catabolic response to HIIT.

Effects of sprint interval training on substrate oxidation in adults living with and without obesity: The i-FLEX study

Metabolic flexibility is the ability to adapt substrate oxidation according to metabolic demand. Exercise increases fat oxidation responses in individuals living with obesity; however, limited research exists on the relationship between substrate oxidation and insulin sensitivity after sprint interval training (SIT). The primary objective was to investigate changes in substrate oxidation at rest and during submaximal exercise, and in insulin sensitivity after 4 weeks of SIT in individuals living with or without obesity. The secondary objective was to investigate correlations between changes in substrate oxidation and insulin sensitivity following SIT. Adults living with obesity (n = 16, body mass index (BMI) = 34.1 kg/m2  ± 3.8) and without obesity (n = 18, BMI = 22.9 kg/m2  ± 1.6) took part in a 4-week SIT intervention. Participants completed three sessions of SIT per week, consisting of repeated sets of a 30-s Wingate separated by 4 m of active recovery. Substrate oxidation at rest and during submaximal exercise was measured using VCO2 /VO2 . Insulin sensitivity was calculated using the Matsuda index. No difference in substrate oxidation at rest was observed for either group (p > 0.05), while a significant increase in fat oxidation was observed in individuals living with obesity [F(1,31) = 14.55, p = 0.001] during the submaximal exercise test. A significant decrease in insulin sensitivity was observed among individuals without obesity [F(1,31) = 5.010, p = 0.033]. No correlations were observed between changes in substrate oxidation and insulin sensitivity (p > 0.05). Following SIT, individuals living with obesity increased submaximal fat oxidation compared to individuals without obesity. No correlations were observed between substrate oxidation and insulin sensitivity. Thus, SIT impacts fat oxidation during exercise in individuals living with obesity while having no such influence on insulin sensitivity.

The Effect of Short-Term Wingate-Based High Intensity Interval Training on Anaerobic Power and Isokinetic Muscle Function in Adolescent Badminton Players

Badminton requires both aerobic fitness and anaerobic ability for high performance. High intensity interval training (HIIT) is a traditional training method for improving fitness. In this study, we investigated whether short-term Wingate-based HIIT is effective for improving anaerobic activity in youth badminton players. Participants included 32 total badminton players in middle school and high school. They were divided into two groups (HIIT and moderate continuous training (MCT)). Training occurred for 4 weeks in total, three times a week, for 30 min each session. A body composition test, isokinetic knee muscle function test (60°/s, 240°/s), Wingate anaerobic power test (30 s × 5 sets), and analysis of heart rate changes were undertaken before and after training. After 4 weeks, body fat decreased in the HIIT group (p = 0.019); they also showed superior anaerobic ability compared to the MCT group. Differences were statistically significant in 3-4 sets (three sets, p = 0.019; four sets, p = 0.021). Regarding fatigue, the HIIT group showed superior fatigue improvement after training and better fatigue recovery ability in 3~5 sets (three sets, p = 0.032; four sets, p = 0.017; five sets, p = 0.003) than the MCT group. Neither group exhibited changes in heart rate during the anaerobic power test after training. Both groups improved in terms of isokinetic knee muscle function at 60°/s with no differences. However, at 240°/s, the HIIT group showed a statistically significant improvement (p = 0.035). Therefore, HIIT for 4 weeks improved the athletes' performance and physical strength.

Adherence to High-Intensity Interval Training in Cardiac Rehabilitation: A REVIEW AND RECOMMENDATIONS

PURPOSE

High-intensity interval training (HIIT) is gaining popularity as a training approach for patients attending cardiac rehabilitation (CR). While the literature has focused on the efficacy of HIIT for improving cardiorespiratory fitness (CRF), particularly when compared with moderate intensity exercise, less emphasis has been placed on adherence to HIIT. The aim of this review was to summarize the current literature regarding adherence to HIIT in CR patients with coronary artery disease.

REVIEW METHODS

A review identified 36 studies investigating HIIT in CR patients with coronary artery disease. Methods and data were extracted for exercise or training adherence (to attendance, intensity, and duration), feasibility of protocols, and CRF. The review summarizes reporting of adherence; adherence to HIIT and comparator/s; the influence of adherence on changes in CRF; and feasibility of HIIT.

SUMMARY

Adherence to the attendance of HIIT sessions was high and comparable with moderate-intensity exercise. However, adherence to the intensity and duration of HIIT was variable and underreported, which has implications for determining the treatment effect of the exercise interventions being compared. Furthermore, additional research is needed to investigate the utility of home-based HIIT and long-term adherence to HIIT following supervised programs. This review provides recommendations for researchers in the measurement and reporting of adherence to HIIT and other exercise interventions to facilitate a sufficient and consistent approach for future studies. This article also highlights strategies for clinicians to improve adherence, feasibility, and enjoyment of HIIT for their patients.

Effects of very low volume high intensity versus moderate intensity interval training in obese metabolic syndrome patients: a randomized controlled study

Physical activity is a cornerstone in the treatment of obesity and metabolic syndrome (MetS). Given the leading physical activity barrier of time commitment and safety concerns about vigorous exercise in high-risk groups, this study aimed to investigate the effects of two extremely time-efficient training protocols (< 30 min time effort per week), either performed as high- (HIIT) or moderate-intensity interval training (MIIT) over 12 weeks, in obese MetS patients. In total, 117 patients (49.8 ± 13.6 years, BMI: 38.2 ± 6.2 kg/m²) were randomized to HIIT (n = 40), MIIT (n = 37) or an inactive control group (n = 40). All groups received nutritional counseling to support weight loss. Maximal oxygen uptake (VO_2max), MetS severity (MetS z-score), body composition and quality of life (QoL) were assessed pre-and post-intervention. All groups significantly reduced body weight (~ 3%) but only the exercise groups improved VO_2max, MetS z-score and QoL. VO_2max (HIIT: + 3.1 mL/kg/min, p < 0.001; MIIT: + 1.2 mL/kg/min, p < 0.05) and MetS z-score (HIIT: − 1.8 units, p < 0.001; MIIT: − 1.2 units, p < 0.01) improved in an exercise intensity-dependent manner. In conclusion, extremely low-volume interval training, even when done at moderate intensity, is sufficiently effective to improve cardiometabolic health in obese MetS patients. These findings underpin the crucial role of exercise in the treatment of obesity and MetS.

Exercise Video Games are Associated with More Positive Affective Response, which Predicts Physical Activity Adherence

Background

A more positive affective valence during exercise is predictive of adherence to physical activity programs. This study examines the relationship between affective response during exercise and longer-term maintenance of physical activity among individuals using exercise video games (EVGs) and standard modalities of physical activity (i.e., walking, cycling).

Methods

Healthy adults (mean age 45.4, SD=14.5) were randomly assigned to a 12-week supervised, thrice weekly program of EVGs (n=93) or Standard exercise (n=96), and were assessed for affect immediately before, at the mid-point, and immediately after one exercise session per week. Participation in moderate-to-vigorous physical activity (MVPA) was conducted at end of treatment (EOT) and 6-month follow up.

Results

EVG participants reported more positive affective valence during exercise compared to Standard participants (b=.63, SE=.08, p<.001), and perceived less exertion (b=.52, SE=.36, p=.04) compared to Standard participants. For both groups, a more positive affective valence during exercise was significantly predictive of continued physical activity at 6-months (b=6.64, SE=2.50, p=.01). EVG participants also showed a significant chronic effect such that week-to-week there were improvements in affect prior to exercise and this effect was significantly associated with greater MPVA at EOT and follow-up (b=21.96, SE=10.10, p=.03 at EOT). Among Standard participants no significant chronic effect was seen over time.

Conclusions

EVGs may provide an effective means of promoting more positive shifts in affective valence both during, and in anticipation of, physical activity that encourages longer-term participation.

Working out the worries: A randomized controlled trial of high intensity interval training in generalized anxiety disorder

BACKGROUND

Aerobic exercise (AE) demonstrated an overall medium treatment effect in anxiety disorders (AD) but there is evidence for an "intensity-response" relationship. High intensity interval training (HIIT) was highly effective on a range of (mental) health parameters. However, so far no randomised-controlled trial (RCT) investigated the efficacy of HIIT in AD.

METHODS

33 patients with generalized anxiety disorder (GAD) were randomly assigned to 12-day HIIT or a training of lower intensity (LIT). Anxiety, comorbid depression, stress-related bodily symptoms and perceived control over anxiety related stimuli (PC) were assessed at baseline, post-training and 30 days after baseline by using the Penn State Worry Questionnaire (PSWQ), the Hamilton Inventories for Anxiety and Depression (Ham-A, Ham-D), the Screening for Somatoform Symptoms-7 (SOMS-7) and the Anxiety Control Questionnaire (ACQ-R).

RESULTS

Both interventions showed moderate or large effects on all clinical measures. However, effects for HIIT were generally about twice as high as for LIT. PC negatively correlated with GAD severity in the whole sample at baseline but an association of training-induced changes in PC and worrying were exclusively detectable in HIIT.

CONCLUSION

HIIT was highly effective and fast acting in GAD. Therefore, it may complement first-line treatment approaches in this condition.

Low-volume high-intensity interval training improves cardiometabolic health, work ability and well-being in severely obese individuals: a randomized-controlled trial sub-study

BACKGROUND

Obesity is associated with impaired health and lower work ability. Increased physical activity is a cornerstone in the treatment of obesity and related risk factors. Recently, high-intensity interval training (HIIT) has emerged as a popular exercise option. However, data regarding the effects on cardiometabolic health, perceived work ability and well-being in severely obese individuals are lacking.

METHODS

Sixty-five obese individuals with sedentary occupation (48.7 ± 9.9 years, BMI: 39.6 ± 7.1 kg/m²) were randomly allocated to an extremely time-efficient HIIT (5 × 1 min at 80-95% maximal heart rate on cycle ergometers, 2×/week for 12 weeks) or an inactive control group (CON). Both groups received nutritional counseling to support weight loss. Primary outcome was maximal oxygen uptake (VO_2max), secondary outcomes were cardiometabolic risk indices, body composition, work ability index (WAI), quality of life (QoL, EQ-5D-5L-questionnaire) and perceived stress (PSQ-questionnaire).

RESULTS

Mean body weight reduction was 5.3 kg [95% confidence interval (95% CI) - 7.3 to - 3.3 kg] in the HIIT group (P < 0.001) and 3.7 kg (95% CI - 5.3 to - 2.1 kg) in CON (P < 0.001), respectively. Only the HIIT group showed significant (P < 0.001) changes in VO_2max [+ 3.5 mL/kg/min (95% CI 2.5 to 4.6 mL/kg/min)], waist circumference [-7.5 cm (95% CI - 9.8 to - 5.1 kg)], mean arterial blood pressure [- 11 mmHg (95% CI - 14 to - 8 mmHg)], WAI [+ 3.0 points (95% CI 1.7 to 4.3 points)] and QoL [+ 10% (95% CI 5 to 16%)]. In CON, none of these parameters improved significantly.

CONCLUSIONS

Low-volume HIIT may induce significant improvements in cardiometabolic health, especially VO_2max, WAI and well-being in obese individuals after only 12 weeks. Our results underpin the wide range of benefits on health and subjective measures through exercise that go well beyond simple weight loss through dietary restriction alone.

TRIAL REGISTRATION

ClinicalTrials.gov Id: NCT03306069. Registered 10 October 2017, https://clinicaltrials.gov/ct2/show/NCT03306069 .

Feasibility of a progressive protocol of high-intensity interval training for overweight/obese, sedentary African American women: a retrospective analysis

Background

African American (AA) women have a higher prevalence of obesity and related metabolic dysfunction and lower level of physical activity compared to white counterparts. Determining feasible exercise alternatives for AA women is, therefore, paramount. Time-efficient high-intensity interval training (HIIT) might be particularly suited for AA women who cite time constraints as a frequent barrier to exercise adherence. The purpose of this study was to assess the feasibility of a 14-week progressive HIIT protocol for previously-sedentary overweight/obese AA women.

Methods

Twenty-eight healthy, premenopausal (age, 20-40 yr), sedentary, nondiabetic, overweight/obese AA women volunteered to participate in the randomized controlled clinical trial from which these data were retrospectively analysed. After assessment, participants were randomly allocated to a HIIT group (n = 14) or a no-exercise control group. The HIIT intervention consisted of 24-min sessions performed three times per week for 14 weeks during which work-interval intensity (75 to 90% of heart rate reserve; HRR) and duration (30 to 60 s) and work/recovery ratio (1:7 to 1:3) were progressed in four stages. Feasibility was assessed based on adherence (attrition rate), perceptual response (RPE) and success rate, which was calculated based on the degree to which target intensities for work intervals were achieved/maintained.

Results

Five of 14 participants (35%) in the HIIT group dropped out during the intervention. One-way repeated-measures ANOVA revealed a significant difference across stages for success rate (p = 0.018) with post-hoc analysis indicating a significant difference between stage 1 and the other stages and stage 4 and the other stages. There was no significant difference in RPE across stages (p = 0.057).

Conclusion

Albeit based on a limited number of participants, we found an attrition rate that was higher than what has been reported previously for HIIT (~ 17.6%) when previously-sedentary overweight/obese AA women performed a protocol with work-interval intensity progressed from 75 to 90% HRR during a 14-week intervention. With respect to intensity, the precipitous drop for achievement of the target HR during the fourth stage (weeks 8-14) for those who did complete the protocol implies that it might be advisable to restrict work-interval intensity to < 90% HRR.

Trial registration

ClinicalTrials.gov. (NCT04293367). Registered 03 March 2020 - Retrospectively registered.

Psychological variables of CrossFit participants: a systematic review

Objective

This study aimed to review the existing literature concerning the psychological variables of CrossFit participants.

Methodology

This review followed the PRISMA guidelines and was documented in the PROSPERO registry (CRD42018091177). Six electronic databases (SCOPUS, PubMed, SPORTDiscus, Web of Science, EMBASE, and Cochrane) were searched from their inception through July 2020. The methodological quality of the studies was assessed.

Results

Thirty-four studies met the inclusion criteria. We observed an increase in satisfaction, clinical addiction, and enjoyment among participants related to exercise, social improvement, and high intrinsic motivation to participate for the purpose of enjoyment, challenge, and affiliation. Perceptions of effort were high among CrossFit participants. Some studies found that the reaction time was impaired after the CrossFit session, whereas others found no changes in mental health, self-esteem, and well-being after training.

Conclusion

Adherence and maintenance of the practice of CrossFit are related to psychological variables such as motivation and satisfaction of basic psychological needs. CrossFit participants demonstrated high perception of effort, intrinsic motivation, and reasons for practice such as enjoyment, challenge, and affiliation. The quality assessment demonstrated the need for more detail in the methods section of future investigations. Additional high-quality studies are needed to investigate the effects of CrossFit training on the mental health of participants.

Electronic supplementary material

The online version of this article (10.1007/s11332-020-00685-9) contains supplementary material, which is available to authorized users.

The Effects of Short-Term High-Intensity Interval Training and Moderate Intensity Continuous Training on Body Fat Percentage, Abdominal Circumference, BMI and VO2max in Overweight Subjects

We aimed to compare the effects of a personalized short-term high-intensity interval training (HIIT) vs. standard moderate intensity continuous training (MICT) on body fat percentage, abdominal circumference, BMI and maximal oxygen uptake (VO_2max) in overweight volunteers. Twenty overweight sedentary volunteers (24.9 ± 2.9y; BMI: 26.1 ± 1 kgm^-2) were randomly assigned to 2 groups, HIIT or MICT. HIIT trained 6 weeks (3-days/week), 40-min sessions as follows: 6-min warm-up, 20-min resistance training (RT) at 70% 1-RM, 8-min HIIT up to 90% of the predicted Maximal Heart Rate (HR_max), 6-min cool-down. MICT trained 6 weeks (3-days/week) 60-min sessions as follows: 6-min warm-up, 20-min RT at 70% 1-RM, 30-min MICT at 60-70% of the predicted HR_max, 4-min cool-down. Two-way ANOVA was performed in order to compare the efficacy of HIIT and MICT protocols, and no significant interaction between training x time was evidenced (p > 0.05), indicating similar effects of both protocols on all parameters analyzed. Interestingly, the comparison of Δ mean percentage revealed an improvement in VO_2max (p = 0.05) together with a positive trend in the reduction of fat mass percentage (p = 0.06) in HIIT compared to MICT protocol. In conclusion, 6 weeks of personalized HIIT, with reduced training time (40 vs. 60 min)/session and volume of training/week, improved VO_2max and reduced fat mass percentage more effectively compared to MICT. These positive results encourage us to test this training in a larger population.

The Physiological, Physical, and Biomechanical Demands of Walking Football: Implications for Exercise Prescription and Future Research in Older Adults

The aim of this investigation was to profile the physiological, physical, and biomechanical responses during walking football. A total of 17 male participants (aged 66 ± 6 years) participated. Heart rate; blood lactate; accelerometer variables (biomechanical load [PlayerLoad™], changes of direction); and rating of perceived exertion were measured. Participants mean percentage of maximum heart rate was 76 ± 6% during the sessions, with rating of perceived exertion across all sessions at 13 ± 2. Blood lactate increased by ∼157% from presession (1.24 ± 0.4 mmol/L) to postsession (3.19 ± 1.7 mmol/L; p ≤ .0005). PlayerLoad™ values of 353 ± 67 arbitrary units were observed, as well as ∼100 changes of direction per session. In conclusion, walking football is a moderate- to vigorous-intensity activity. The longitudinal health benefits of walking football remain to be elucidated, particularly on bone health, cardiovascular fitness, and social and mental well-being.

Influence of daily beer or ethanol consumption on physical fitness in response to a high-intensity interval training program. The BEER-HIIT study

BACKGROUND

High-intensity interval training (HIIT) is an effective approach to improve physical fitness, but consuming beer, which is a regular practice in many physically active individuals, may interfere with these effects. The purposes of this study were to investigate the effects of a 10-week (2 days/week) HIIT program on cardiorespiratory fitness, muscle strength and power parameters, and also to assess the possible influence on them of a moderate consumption of beer (at least from Monday to Friday) or its alcohol equivalent.

METHODS

Young (24 ± 6 years old) healthy adults (n = 73, 35 females) were allocated to five groups. Four groups participated in the HIIT intervention program while the fifth group was a control Non-Training group (n = 15). Participants in the training groups chose whether they preferred receiving alcohol or alcohol-free beverages. Those choosing alcohol were randomized to either beer or ethanol intake: (i) T-Beer group (alcohol beer, 5.4%; n = 13) or (ii) T-Ethanol (sparkling water with vodka, 5.4%; n = 14). Those choosing alcohol-free intake were randomized to (iii) T-Water group (sparkling water, 0.0%; n = 16), or (iv) T-0.0Beer group (alcohol-free beer, 0.0%; n = 15). Men ingested 330 ml of the beverage at lunch and 330 ml at dinner; women ingested 330 ml at dinner. Before and after the intervention, maximal oxygen uptake in absolute and relative terms (VO2max.), maximal heart rate, total test duration, hand grip strength and four types of vertical jumps were measured.

RESULTS

HIIT induced significant improvements in absolute and relative values of VO2max, and total test duration (all p < 0.05) in all the training groups; also, clinical improvements were found in hand grip strength. These positive effects were not influenced by the regular intake of beer or alcohol. No changes in the vertical jumps occurred in any of the groups.

CONCLUSIONS

A moderate beer or alcohol intake does not mitigate the positive effect of a 10-week HIIT on physical fitness in young healthy adults.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03660579. Registered 20 September 2018. Retrospectively registered.

Adherence and drop-out in randomized controlled trials of exercise interventions in people with multiple sclerosis: A systematic review and meta-analyses

BACKGROUND

The short-term benefits of exercise in people with multiple sclerosis (MS) are well established. To sustain benefits exercise needs to continue long-term. Despite important clinical implications, no systematic reviews have synthesized evidence on adherence and drop-out in MS exercise interventions.

OBJECTIVES

1) To summarize reported adherence and drop-out data from randomized controlled trials (RCTs) of exercise interventions, and 2) identify moderators related to adherence and drop-out.

METHODS

Nine databases were electronically searched in October 2018. Included studies were RCTs of exercise interventions in adults with MS published from January 1993 to October 2018. Abstracts and full texts were independently screened and selected for inclusion by two reviewers. Methodological quality was assessed using the TESTEX rating scale.

RESULTS

Ninety three articles reporting 81 studies were included. Forty one studies (51%) reported both adherence and drop-out data during the intervention period with three (4%) also reporting follow-up data. Of the 41 studies, < 25% pre-defined adherence or described how adherence was measured. Meta-analyses of 59 interventions (41 studies) showed a pooled adherence estimate of 0.87 (95% CI 0.83 to 0.90) and 0.73 (CI 0.68-0.78) when including drop-outs. Mean age, proportion of females and intervention duration were inversely associated with adherence.

CONCLUSION

Little consensus existed on definition of adherence or determination of drop-out in MS exercise studies, with reporting generally of poor quality, if done at all. Hence it is largely unknown what can moderate adherence and whether exercise continued following an exercise intervention. Researchers should ensure clear transparent measurement and reporting of adherence and drop-out data in future trials.

Reducing training frequency from 3 or 4 sessions/week to 2 sessions/week does not attenuate improvements in maximal aerobic capacity with reduced-exertion high-intensity interval training (REHIT)

In the present randomised-controlled trial we investigated the effect of reduced-exertion high-intensity interval training (REHIT) training frequency (2, 3, or 4 sessions/week for 6 weeks) on maximal aerobic capacity in 42 inactive individuals (13 women; mean ± SD age: 25 ± 5 years, maximal aerobic capacity: 35 ± 5 mL·kg^-1·min^-1). Changes in maximal aerobic capacity were not significantly different between the 3 groups (2 sessions/week: +10.2%; 3 sessions/week: +8.1%; 4 sessions per week: +7.3%). In conclusion, a training frequency of 2 sessions/week is sufficient for REHIT to improve maximal aerobic capacity. Novelty We demonstrate that reducing REHIT training frequency from 3 or 4 to 2 sessions/week does not attenuate improvements in the key health marker of maximal aerobic capacity.

A Qualitative Analysis of an Aerobic Interval Training Programme for Obese Outpatients Carried Out in a Hospital Context

Purpose: To describe the experience of obese adults following participation in an indoor aerobic interval training (AIT) intervention. Methodology: Qualitative, in-depth semi-structured individual interviews, using phenomenology, with 24 obese adults (body mass index (BMI) ≥30 kg/m²) from the Endocrinology Department, at the Severo Ochoa Hospital in Leganés (Madrid). Questions were related to: (a) The physical activity (PA) programme, (b) their perspectives of the activity and exercise environment and (c) the perceived benefits from participation. Data were analysed with a constant comparison approach. Results: The main patients' reasons for beginning the programme were motivations to take part including weight loss, health improvement and doctors' recommendation. Also, patients showed doubts and feelings of apprehension at the beginning of the intervention. Patients highlighted the role of the instructor, feelings of exercising in a safe environment, a good intervention and accessibility of the facility. They reported an improvement in their quality of life and recommended continuing the program. Conclusions: (1) Common themes in the qualitative analysis included enjoyment of the activity and a desire to maintain physical fitness, (2) AIT was perceived as a suitable exercise programme for this population and (3) recommendations for further investigation to understand the role of PA programmes for people with obesity.