Heterogeneous responses of personalised high intensity interval training on type 2 diabetes mellitus and cardiovascular disease risk in young healthy adults

Sex Differences in Effects of Exercise on Physical Function in Aging: A Systematic Review with Meta-Analysis

PURPOSE

Our objective was to synthesize and determine whether there are sex differences in physical function following exercise interventions in older adults.

MATERIALS AND METHODS

A systematic search was conducted in four databases from inception to July 8th, 2023 searching for prospective trials that conducted exercise interventions in older adults and results for physical function were reported by sex. Pooled standardized mean differences (SMDs) with their 95% confidence intervals (CIs) were estimated using a randomeffects method. The Sidik-Jonkman estimator was used to calculate the variance of heterogeneity (I²).

RESULTS

A total of 19 studies involving 20,133 older adults (mean age ≥60 years, 33.7% female) were included. After exercise interventions, males reported significantly greater pre-post changes compared to females for upper body strength (SMD=-0.40, 95% CI: -0.71 to -0.09; I²=75.6%; n=8), lower body strength (SMD=-0.32, 95% CI: -0.55 to -0.10; I²=52.0%; n=11), and cardiorespiratory fitness (SMD=-0.29, 95% CI: -0.48 to -0.10; I²=89.1%; n=12). Conversely, the pooled SMDs showed a significant effect favoring females for motor fitness (SMD=0.21, 95% CI: 0.03 to 0.39; I²=0%; n=7). Limited and inconsistent results were observed for flexibility.

CONCLUSIONS

Our study suggests the existence of sex-related differences on physical function after an exercise intervention in the older population.

Physical activity lowers all-cause and cardio-cerebrovascular mortality in adults with coronary heart disease

BACKGROUND

The health outcomes and their adherence to guideline-based secondary prevention physical activity in US patients with coronary heart disease (CHD), together with the association between physical activity (PA) and mortality risk, were investigated.

METHODS

Data on CHD patients (aged 18 to 85 years) was acquired from the US National Health and Nutrition Examination Survey (NHANES) 1999-2018. The patients were divided into four groups according to the level and frequency of PA, namely, a) sedentary (n = 1178), b) moderate PA (moderate, n = 270), c) vigorous PA once or twice per week (vigorous ≤2×, n = 206), and d) vigorous PA three or more times per week (vigorous >2×, n = 598). Logistic analysis was used to determine the relationship between PA and all-cause or cardio-cerebrovascular mortality in CHD patients.

RESULTS

A total of 2252 patients with CHD were enrolled, of whom 47.69% reported adequate PA. During the investigation, there were 296 (13.14%) cardio-cerebrovascular and 724 (32.15%) all-cause deaths. The incidence of all-cause or cardio-cerebrovascular death was lowest in the vigorous ≤2× group. Patients who undertook vigorous PA ≤ 2× showed the lowest risk of all-cause (odds ratio 0.32; 95% confidence interval 0.22-0.47; P < 0.01) or cardio-cerebrovascular death (odds ratio 0.43; 95% confidence interval 0.25-0.73; P < 0.01) relative to those in the sedentary group. More frequent vigorous PA did not lead to improved benefits.

CONCLUSIONS

Vigorous PA once or twice per week was more effective for reducing all-cause and cardio-cerebrovascular mortality compared with patients performing no or a moderate level of PA in US adults with CHD.

Characterizing the interindividual postexercise hypotension response for two order groups of concurrent training in patients with morbid obesity

Background: Postexercise hypotension (PEH) is a common physiological phenomenon occurring immediately after endurance training (ET), resistance training (RT), and ET plus RT, also termed concurrent training (CT); however, there is little knowledge about the interindividual and magnitude response of PEH in morbidly obese patients.

Aim: The aims of this study were (1) to investigate the effect of CT order (ET + RT vs. RT + ET) on the blood pressure responses; 2) characterize these responses in responders and nonresponders, and 3) identify potential baseline outcomes for predicting blood pressure decreases as responders.

Methods: A quasi-experimental study developed in sedentary morbidly obese men and women (age 43.6 ± 11.3 years; body mass index [BMI] ≥40 kg/m²) was assigned to a CT group of ET plus RT (ET + RT; n = 19; BMI 47.8 ± 16.7) or RT plus ET order group (RT + ET; n = 17; BMI 43.0 ± 8.0). Subjects of both groups received eight exercise sessions over four weeks. Primary outcomes include systolic (SBP), diastolic (DBP), mean arterial pressure [MAP], heart rate at rest [HR], and pulse pressure [PP] measurements before and after 10 min post-exercise. Secondary outcomes were other anthropometric, body composition, metabolic, and physical fitness parameters. Using the delta ∆SBP reduction, quartile categorization (Q) in “high” (Rs: quartile 4), “moderate” (MRs: quartile 3), “low” (LRs: quartile 2), and “nonresponders” (NRs: quartile 1) was reported.

Results: Significant pre–post changes were observed in ET + RT in session 2 for SBP (131.6 vs. 123.4 mmHg, p = 0.050) and session 4 (131.1 vs. 125.2 mmHg, p = 0.0002), while the RT + ET group showed significant reductions in session 4 (134.2 vs. 125.3 mmHg, p < 0.001). No significant differences were detected in the sum of the eight sessions for SBP (∑∆SBP) between ET + RT vs. RT + ET (−5.7 vs. −4.3 mmHg, p = 0.552). Interindividual analyses revealed significant differences among frequencies comparing Q1 “NRs” (n = 8; 22.2%), Q2 “LRs” (n = 8; 22.2%), Q3 “MRs” (n = 9; 25.0%), and Q4 “HRs” (n = 11; 30.5%), p < 0.0001. Quartile comparisons showed significant differences in SBP changes (p = 0.035). Linear regression analyses revealed significant association between ∑∆SBP with body fat % (β –3.826, R² 0.211 [21.1%], p = 0.031), skeletal muscle mass [β –2.150, R² 0.125 (12.5%), p = 0.023], fasting glucose [β 1.273, R² 0.078 (7.8%), p = 0.003], triglycerides [β 0.210, R² 0.014 (1.4%), p = 0.008], and the 6-min walking test [β 0.183, R² 0.038 (3.8%), p = 0.044].

Conclusion: The CT order of ET + RT and RT + ET promote a similar ‘magnitude’ in the postexercise hypotensive effects during the eight sessions of both CT orders in 4 weeks of training duration, revealing “nonresponders” and ‘high’ responders that can be predicted from body composition, metabolic, and physical fitness outcomes.

Effects of high-intensity and moderate-intensity exercise training on cardiopulmonary function in patients with coronary artery disease: A meta-analysis

Purpose

The study aims to evaluate the effects of high-intensity and moderate-intensity exercise training on cardiopulmonary function and exercise endurance in patients with coronary artery diseases (CAD).

Methods

We performed a systematic search of the English and Chinese databases from their inception to March 2022. Randomized controlled trials (RCTs) were included to compare high-intensity and moderate-intensity exercise training on cardiopulmonary function in patients with CAD. The primary outcomes included peak oxygen uptake (peak VO₂) and anaerobic threshold (AT). The secondary outcomes included left ventricular ejection fraction (LVEF), exercises duration (ED), respiratory exchange ratio (RER), resting heart rate (RHR), peak heart rate (PHR) and oxygen pulse (O₂ pulse). The continuous variables were expressed as mean differences (MD) along with their corresponding standard deviations (SD), and the I² test was applied in the assessment of heterogeneity.

Results

After systematically literature search, 19 studies were finally selected for our meta-analysis (n = 1,036), with 511 patients in the experimental group (high-intensity exercise) and 525 patients in the control group (moderate-intensity exercise). The results showed that high-intensity exercise significantly increased patients' Peak VO₂ [MD = 2.67, 95% CI (2.24, 3.09), P < 0.00001], LVEF [MD = 3.60, 95% CI (2.17, 5.03), P < 0.00001], ED [MD = 37.51, 95% CI (34.02, 41.00), P < 0.00001], PHR [MD = 6.86, 95% CI (4.49, 9.24), P < 0.00001], and O₂ pulse [MD = 0.97, 95% CI (0.34, 1.60), P = 0.003] compared with moderate-intensity exercise. However, there were no significant differences in AT [MD = 0.49, 95% CI (−0.12, 1.10), P = 0.11], RER [MD = 0.00, 95% CI (−0.01, 0.02), P = 0.56], and RHR [MD = 1.10, 95% CI (−0.43, 2.63), P = 0.16].

Conclusion

Our results show that high-intensity exercise training has more significant positive effects compared with moderate-intensity exercise training in improving peak VO₂, LVEF, ED, PHR and O₂ pulse in patients with CAD, while no significant differences were observed in AT, RER and RHR. To sum up, high-intensity exercise training is better than moderate-intensity exercise training in improving cardiopulmonary function and exercise endurance in patients with CAD.

Systematic review registration

PROSPERO (CRD42022328475), https://www.crd.york.ac.uk/PROSPERO/.

Mechanistic Effects of Aerobic Exercise in Alzheimer's Disease: Imaging Findings From the Pilot FIT-AD Trial

Despite strong evidence from animal models of Alzheimer's disease (AD) supporting aerobic exercise as a disease-modifying treatment for AD, human mechanistic studies are limited with mixed findings. The objective of this pilot randomized controlled trial was to examine the effects of 6-month aerobic exercise on hippocampal volume, temporal meta-regions of interest (ROI) cortical thickness, white matter hyperintensity (WMH) volume, and network failure quotient (NFQ), measured with MRI, in community-dwelling older adults with AD dementia. Additionally, the relationships between 6- and 12-month changes in MRI biomarkers and the AD Assessment Scale-Cognition (ADAS-Cog) were examined. Sixty participants were randomized, but one was excluded because baseline MRI failed quality control: 38 randomized to cycling and 21 to stretching. The intervention was moderate-intensity cycling for 20-50 mins, three times a week for 6 months. Control was low-intensity stretching. The study outcomes include hippocampal volume, temporal meta-ROI cortical thickness, WMH volume, and NFQ. Outcomes were measured at baseline, 6 months, and 12 months. The sample averaged 77.3 ± 6.3 years old with 15.6 ± 2.9 years of education and 53% men. Both groups experienced significant declines over 6 months in hippocampal volume (2.64% in cycling vs. 2.89% in stretching) and temporal meta-ROI cortical thickness (0.94 vs. 1.54%), and over 12 months in hippocampal volume (4.47 vs. 3.84%) and temporal meta-ROI cortical thickness (2.27 vs. 1.79%). These declines did not differ between groups. WMH volume increased significantly with the cycling group increasing less (10.9%) than stretching (24.5%) over 6 months (f = 4.47, p = 0.04) and over 12 months (12.1 vs. 27.6%, f = 5.88, p = 0.02). NFQ did not change significantly over time. Pairwise correlational analyses showed a significant negative correlation between 6-month changes in hippocampal volume and ADAS-Cog (r = -0.34, p < 0.05). To conclude, aerobic exercise may reduce the decline in hippocampal volume and temporal meta-ROI cortical thickness during the intervention period, but the effect sizes are likely to be very small and dose-dependent and reverse once the intervention stops. Aerobic exercise is effective on slowing down WMH progression but has no effect on NFQ. Hippocampal atrophy was associated with cognitive decline during the intervention period. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT01954550.

Indicators of response to exercise training: a systematic review and meta-analysis

BACKGROUND

Means-based analysis of maximal rate of oxygen consumption (VO2max) has traditionally been used as the exercise response indicator to assess the efficacy of endurance (END), high intensity interval (HIIT) and resistance exercise training (RET) for improving cardiorespiratory fitness and whole-body health. However, considerable heterogeneity exists in the interindividual variability response to the same or different training modalities.

OBJECTIVES

We performed a systematic review and meta-analysis to investigate exercise response rates in the context of VO2max: (1) in each training modality (END, HIIT and RET) versus controls, (2) in END versus either HIIT or RET and (3) exercise response rates as measured by VO2max versus other indicators of positive exercise response in each exercise modality.

METHODS

Three databases (EMBASE, MEDLINE, CENTRAL) and additional sources were searched. Both individual response rate and population average data were incorporated through continuous data, respectively. Of 3268 identified manuscripts, a total of 29 studies were suitable for qualitative synthesis and a further 22 for quantitative. Stratification based on intervention duration (less than 12 weeks; more than or equal to 12 weeks) was undertaken.

RESULTS

A total of 62 data points were procured. Both END and HIIT training exhibited differential improvements in VO2max based on intervention duration. VO2max did not adequately differentiate between END and HIIT, irrespective of intervention length. Although none of the other exercise response indicators achieved statistical significance, LT and HRrest demonstrated common trajectories in pooled and separate analyses between modalities. RET data were highly limited. Heterogeneity was ubiquitous across all analyses.

CONCLUSIONS

The potential for LT and HRrest as indicators of exercise response requires further elucidation, in addition to the exploration of interventional and intrinsic sources of heterogeneity.

International Exercise Recommendations in Older Adults (ICFSR): Expert Consensus Guidelines

The human ageing process is universal, ubiquitous and inevitable. Every physiological function is being continuously diminished. There is a range between two distinct phenotypes of ageing, shaped by patterns of living - experiences and behaviours, and in particular by the presence or absence of physical activity (PA) and structured exercise (i.e., a sedentary lifestyle). Ageing and a sedentary lifestyle are associated with declines in muscle function and cardiorespiratory fitness, resulting in an impaired capacity to perform daily activities and maintain independent functioning. However, in the presence of adequate exercise/PA these changes in muscular and aerobic capacity with age are substantially attenuated. Additionally, both structured exercise and overall PA play important roles as preventive strategies for many chronic diseases, including cardiovascular disease, stroke, diabetes, osteoporosis, and obesity; improvement of mobility, mental health, and quality of life; and reduction in mortality, among other benefits. Notably, exercise intervention programmes improve the hallmarks of frailty (low body mass, strength, mobility, PA level, energy) and cognition, thus optimising functional capacity during ageing. In these pathological conditions exercise is used as a therapeutic agent and follows the precepts of identifying the cause of a disease and then using an agent in an evidence-based dose to eliminate or moderate the disease. Prescription of PA/structured exercise should therefore be based on the intended outcome (e.g., primary prevention, improvement in fitness or functional status or disease treatment), and individualised, adjusted and controlled like any other medical treatment. In addition, in line with other therapeutic agents, exercise shows a dose-response effect and can be individualised using different modalities, volumes and/or intensities as appropriate to the health state or medical condition. Importantly, exercise therapy is often directed at several physiological systems simultaneously, rather than targeted to a single outcome as is generally the case with pharmacological approaches to disease management. There are diseases for which exercise is an alternative to pharmacological treatment (such as depression), thus contributing to the goal of deprescribing of potentially inappropriate medications (PIMS). There are other conditions where no effective drug therapy is currently available (such as sarcopenia or dementia), where it may serve a primary role in prevention and treatment. Therefore, this consensus statement provides an evidence-based rationale for using exercise and PA for health promotion and disease prevention and treatment in older adults. Exercise prescription is discussed in terms of the specific modalities and doses that have been studied in randomised controlled trials for their effectiveness in attenuating physiological changes of ageing, disease prevention, and/or improvement of older adults with chronic disease and disability. Recommendations are proposed to bridge gaps in the current literature and to optimise the use of exercise/PA both as a preventative medicine and as a therapeutic agent.

Sprint interval training vs. combined aerobic + resistance training in overweight women with type 2 diabetes

BACKGROUND

Aerobic and resistance training have known efficacy for treating type2 diabetes (T2D). Less is known about interval training in this population. We examined the effects of sprint interval (SIT) and combined aerobic + resistance (COMB) training on HbA1C and (Primary Outcome) in participants with T2D. Secondary outcomes included HOMA-IR and standard clinical chemistries. Exploratory/Tertiary included immerging cardiovascular disease risk indices.

METHODS

Participants (N.=52; 45-60y, BMI>30kg/m², HbA1c, ≥6.5%) were randomly assigned to either SIT (N.=17), COMB (N.=17) or usual care control (Control, N.=18) for 10-weeks. Data were analyzed by ANOVA and effect sizes estimated using Cohen's D (CD).

RESULTS

We observed significant reductions in HbA1c for SIT (-1.82%, 95% CI, -2.50, -1.14) and COMB (-1.24%, 95% CI, -2.19, -0.29), but not Control (0.02%, 95% CI, -0.67, 0.71). Secondary outcome analysis demonstrated significant reductions in HOMA-IR for SIT (-4.89, 95% CI, -6.94, -2.83) and COMB training (-2.90, 95% CI, -5.00, -0.79), but not Control (-0.44, 95% CI, -3.44, 2.46). Effect size estimates and accompanying confidence interval bound were deemed "large" for HBA1c and moderate-to-large for HOMA-IR. Non-significant changes for the Control group were deemed "trivial." Both analyses were significant vs. Control. Similar patterns were observed for most standard laboratory measures and tertiary outcomes.

CONCLUSIONS

Our results demonstrated that SIT and COMBO training are effective exercise training regimens in overweight women with T2D independently of changes in body mass.

The Effect of Low-Volume High-Intensity Interval Training on Body Composition and Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence for the efficacy of low-volume high-intensity interval training (HIIT) for the modulation of body composition is unclear.

OBJECTIVES

We examined the effect of low-volume HIIT versus a non-exercising control and moderate-intensity continuous training (MICT) on body composition and cardiorespiratory fitness in normal weight, overweight and obese adults. We evaluated the impact of low-volume HIIT (HIIT interventions where the total amount of exercise performed during training was ≤ 500 metabolic equivalent minutes per week [MET-min/week]) compared to a non-exercising control and MICT.

METHODS

A database search was conducted in PubMed (MEDLINE), EMBASE, CINAHL, Web of Science, SPORTDiscus and Scopus from the earliest record to June 2019 for studies (randomised controlled trials and non-randomised controlled trials) with exercise training interventions with a minimum 4-week duration. Meta-analyses were conducted for between-group (low-volume HIIT vs. non-exercising control and low-volume HIIT vs. MICT) comparisons for change in total body fat mass (kg), body fat percentage (%), lean body mass (kg) and cardiorespiratory fitness.

RESULTS

From 11,485 relevant records, 47 studies were included. No difference was found between low-volume HIIT and a non-exercising control on total body fat mass (kg) (effect size [ES]: - 0.129, 95% confidence interval [CI] - 0.468 to 0.210; p = 0.455), body fat (%) (ES: - 0.063, 95% CI - 0.383 to 0.257; p = 0.700) and lean body mass (kg) (ES: 0.050, 95% CI - 0.250 to 0.351; p = 0.744), or between low-volume HIIT and MICT on total body fat mass (kg) (ES: - 0.021, 95% CI - 0.272 to 0.231; p = 0.872), body fat (%) (ES: 0.005, 95% CI - 0.294 to 0.304; p = 0.974) and lean body mass (kg) (ES: 0.030, 95% CI - 0.167 to 0.266; p = 0.768). However, low-volume HIIT significantly improved cardiorespiratory fitness compared with a non-exercising control (p < 0.001) and MICT (p = 0.017).

CONCLUSION

These data suggest that low-volume HIIT is inefficient for the modulation of total body fat mass or total body fat percentage in comparison with a non-exercise control and MICT. A novel finding of our meta-analysis was that there appears to be no significant effect of low-volume HIIT on lean body mass when compared with a non-exercising control, and while most studies tended to favour improvement in lean body mass with low-volume HIIT versus MICT, this was not significant. However, despite its lower training volume, low-volume HIIT induces greater improvements in cardiorespiratory fitness than a non-exercising control and MICT in normal weight, overweight and obese adults. Low-volume HIIT, therefore, appears to be a time-efficient treatment for increasing fitness, but not for the improvement of body composition.

Anthropometric, Cardiopulmonary and Metabolic Benefits of the High-Intensity Interval Training Versus Moderate, Low-Intensity or Control for Type 2 Diabetes: Systematic Review and Meta-Analysis

Abstract: This study aims to evaluate the effectiveness of high-intensity interval training compared with no intervention and other types of training interventions for people with Type 2 Diabetes. A systematic review and meta-analysis of randomized controlled trials that used high-interval intensity training to improve anthropometric, cardiopulmonary and metabolic conditions were conducted. The search was performed during October-December 2017 using the databases PubMed, Web of Science and Physiotherapy Evidence Database (PEDro). The methodological quality of the studies was evaluated using the PEDro scale. A total of 10 articles were included in this meta-analysis. After statistical analysis, favorable results were obtained for high-Intensity Interval Training compared with control (non-intervention): [Weight: Standardized mean difference (SMD) = -2.09; confidence interval (CI) 95%: (-3.41; -0.78); body-mass index: SMD = -3.73; CI 95%: (-5.53; -1.93); systolic blood pressure: SMD = -4.55; CI 95%: (-8.44; -0.65); VO2max: SMD = 12.20; CI 95%: (0.26; 24.14); HbA1c: SMD = -3.72; CI 95%: (-7.34; -0.10)], moderate intensity continuous training: [body-mass index: SMD = -0.41; CI 95%: (-0.80; -0.03); VO2max: SMD = 1.91; CI 95%: (0.18; 3.64)], and low intensity training: [Weight: SMD = -2.06; CI 95%: (-2.80; -1.31); body-mass index: SMD = -3.04; CI 95%: (-5.16; -0.92); systolic blood pressure: SMD = -2.17; CI 95%: (-3.93; -0.41); HbA1c: SMD = -1.58; CI 95%: (-1.84; -1.33)]. The results show that high-intensity interval training can be a useful strategy in order to improve anthropometric, cardiopulmonary and metabolic parameters in people with Type 2 diabetes. Despite this, it could be essential to clarify and unify criteria in the intervention protocols, being necessary new lines of research.

Effects of different exercise modalities on novel hepatic steatosis indices in overweight women with type 2 diabetes

BACKGROUND/AIMS

Fatty liver is a clinical and pathologic condition in individuals with type 2 diabetes (T2D). The purpose of this study is to examine the effects of different exercise modalities on non-alcoholic fatty liver indices (fatty liver index [FLI], lipid accumulation product [LAP], hepatic steatosis index [HSI], and Framingham Steatosis Index [FSI]) in women with T2D.

METHODS

Fifty-two women with T2D and a mean age of 55.07±5.92 yrs, body mass index (BMI) 28.94±4.09 kg/m2 , and hemoglobin A1c (HbA1c) 9.41±0.82% were randomized to a sprint interval training (SIT) (n=17), combined aerobic and resistance (A+R) training (n=17), or control group (n=18) for 10 weeks. Two-way repeated analysis of variance (ANOVA) was used to find differences between groups and the effects of time and Time×Group interactions after 10 weeks on non-alcoholic fatty liver indices. After this, ANOVA models were constructed to determine the effects of group allocation and change in non-alcoholic fatty liver indices.

RESULTS

There were significant time interactions for FLI (P<0.001), HSI (P<0.001), and LAP (P<0.001). Also, there were significant Time×Group interactions for fasting blood glucose (P=0.034), and HbA1c (P=0.006).

CONCLUSION

Results highlight that exercise training, independent of mode of training, is an effective strategy to improve some indices related to hepatic steatosis and blood glucose profiles in women with T2D.

Effects of sprint interval or combined aerobic and resistance training on myokines in overweight women with type 2 diabetes: A randomized controlled trial

Our primary aim was to assess the effects of two different training modalities: sprint interval training (SIT) or combined aerobic and resistance training (A + R) on circulating myokines related to metabolic profile and adiposity in type 2 diabetes (T2D). Fifty-two overweight women with T2D [55 ± 6 yrs., BMI 28.9 ± 4.1 kg/m², HbA1c 9.4 ± 0.82% (79 mmol/mol)] were randomized to SIT (n = 17), A + R training (n = 17) or control (n = 18) for 10 weeks. Myokines, metabolic outcomes, body composition and cardiorespiratory fitness were assessed at baseline and 48 hours after the last training session/control period. Relationships between myokines and other variables were investigated via linear regression models. Completion rate was 81%. There was no effect of either exercise modality on any myokine. Interlukin-15 decreased over time irrespective of group assignment (p = 0.02). Aerobic capacity (p = 0.01), fasting glucose (p = 0.03) and HbA1c (p = 0.006) improved significantly and similarly in both exercise groups compared to controls. Insulin (p = 0.02), weight (p = 0.020, body max index (BMI) (p = 0.01) decreased significantly over time irrespective of group. Changes in myokines were unrelated to changes in body composition or metabolic profile. Neither SIT or A + R training altered myokines measured 48 h after exercise in T2D, despite improving aerobic capacity and glucose homeostasis relative to controls. Future studies are needed to elucidate the time course and clinical relevance of putative myokine responses to exercise in this and other cohorts.

Prevalence of Non-responders for Blood Pressure and Cardiometabolic Risk Factors Among Prehypertensive Women After Long-Term High-Intensity Interval Training

Background: Exercise is known to improve cardiometabolic outcomes; however, results are typically reported as mean values, and there is wide interindividual variability in terms of response that has not been explored in populations at risk for hypertension. Our aim was to investigate both the effects on and the prevalence of non-responders (NRs) for decreasing blood pressure (BP) and other risk factors among prehypertensive women after long-term high-intensity interval training (HIIT). A secondary aim was to report potential variables that can predict decreases in BP after HIIT. Methods: Sedentary overweight/obese women (age 35.9 ± 5.4 year; body mass index [BMI] 30.9 ± 6.2 kg/m2) were assigned to a prehypertensive (PreHTN; N = 44) or normotensive (NT; N = 40) group according to their ambulatory BP at baseline. Subjects underwent a thrice-weekly 16-week HIIT program (7-10 × 1 min exercise with 2 min of rest). Training-induced changes in body composition and cardiovascular, metabolic, strength, and endurance performance markers were measured, and the prevalence of NRs was reported as a percentage. All outcomes were analyzed by multivariable regression. Results: Statistically significant (P < 0.05) decreases in systolic BP (SBP) were detected in the PreHTN group (Δ -8 mmHg) compared with baseline, whereas the NT group (Δ + 3 mmHg) showed a non-significant increase in SBP. Diastolic BP (DBP) was significantly decreased in the PreHTN group (Δ -5.8 mmHg) and non-significantly decreased (Δ -2 mmHg) in the NT group. Also, there were significant differences (P < 0.0001) in the prevalence of NRs based on SBP between the PreHTN and NT groups (11.4 vs. 68.8%), but similar prevalence of NRs based on DBP. SBP alone was a powerful predictive factor for a beneficial SBP reduction, explaining 51.2% of the results, which was similar to other more complex models tested. Conclusion: The prevalence of NRs based on SBP and DBP was different between prehypertensive and normotensive subjects after 16 weeks of HIIT. Other comorbidities such as body composition and metabolic outcomes showed almost similar modifications between prehypertensive and normotensive subjects, being the most basic predictive factor for BP reduction baseline SBP, which we refer to as 'BP health status' (51.2%). This improvement in BP was accompanied by other known improvements of HIIT on body composition, metabolic and endurance performance in both study cohorts. Trial Registration: ClinicalTrials.gov ID: NCT03000140 (Register 20 December, 2016).

Variability in Individual Response to Aerobic Exercise Interventions Among Older Adults

Although a plethora of evidence supports the benefits of exercise among older adults, a majority of studies have emphasized group differences, while giving little, if any, attention to individual differences. Given the lack of data on variability in response, the present review examined how nonresponse to aerobic exercise has been defined in older adult populations and characteristics associated with nonresponse among older adults. The results of this review suggest that interindividual variability in response of maximal oxygen consumption to aerobic exercise interventions is prevalent among older adults (1.4-63.4%); age, sex, race, and body mass index may not be critical determinants of nonresponse; whereas health status, baseline fitness, and exercise dose appear important. Future intervention studies should evaluate and report the variability in individual response of older adults to exercise; investigators should develop programs that allow for modification of components to assist older adults in achieving optimal benefit from exercise programs.

Type 2 diabetes mellitus risk and exercise: is resistin involved?

Obesity and associated disorders such as type 2 diabetes mellitus (T2DM) pose an increasing risk to the health of both individuals and society. Adipose tissue is an active endocrine organ, secreting many hormones, known as adipokines. Evidence suggests that one suggest adipokine, resistin, may be elevated in the plasma of individuals with T2DM, and early reports indicated that this may contribute to the impaired glucose tolerance and insulin resistance observed in T2DM, hence its name, resistin, however subsequent evidence suggests it may have a proinflammatory role. Performing regular exercise and dietary interventions improve insulin sensitivity and glucose tolerance in the majority of individuals with T2DM, and we hypothesized that plasma resistin levels may drop in individuals following a long term aerobic and/or resistance exercise intervention program. Articles analyzing the effects of exercise on serum resistin levels were therefore analyzed. Articles were selected and analyzed based on a minimum aerobic and/or resistance training program of 2 sessions per week for 12 weeks. Plasma resistin levels decreased following either endurance aerobic exercise and/or resistance training plans in individuals with obesity and/or insulin resistance, although this was not related to BMI change. Exercise intervention programs generally showed potentially beneficial changes in plasma resistin concentrations. It is possible these effects are mediated through exercise-induced decreases in inflammation via anti-inflammatory cytokine release rather than alterations in glucose metabolism and reductions in BMI per se. A possible link between resistin, exercise and T2DM is discussed.

High-intensity interval and moderate-intensity continuous training elicit similar enjoyment and adherence levels in overweight and obese adults

BACKGROUND

High-intensity interval training (HIIT) has been shown to improve cardiometabolic health during supervised lab-based studies but adherence, enjoyment, and health benefits of HIIT performed independently are yet to be understood. We compared adherence, enjoyment, and cardiometabolic outcomes after 8 weeks of HIIT or moderate-intensity continuous training (MICT), matched for energy expenditure, in overweight and obese young adults.

METHODS

17 adults were randomized to HIIT or MICT. After completing 12 sessions of supervised training over 3 weeks, participants were asked to independently perform HIIT or MICT for 30 min, 4 times/week for 5 weeks. Cardiometabolic outcomes included cardiorespiratory fitness (VO2 peak), lipids, and inflammatory markers. Exercise enjoyment was measured by the validated Physical Activity Enjoyment Scale.

RESULTS

Exercise adherence (93.4 ± 3.1% vs. 93.1 ± 3.7%, respectively) and mean enjoyment across the intervention (100.1 ± 4.3 vs. 100.3 ± 4.4, respectively) were high, with no differences between HIIT and MICT (p > .05). Similarly, enjoyment levels did not change over time in either group (p > .05). After training, HIIT exhibited a greater decrease in low-density lipoprotein cholesterol than MICT (-0.66 mmol L-1 vs. -0.03 mmol L-1, respectively) and a greater increase in VO2 peak than MICT (p < .05, +2.6 mL kg min-1 vs. +0.4 mL kg min-1, respectively). Interleukin-6 and C-reactive protein increased in HIIT (+0.5 pg mL-1 and + 31.4 nmol L-1, respectively) and decreased in MICT (-0.6 pg mL-1 and -6.7 nmol L-1, respectively, p < .05).

CONCLUSIONS

Our novel findings suggest that HIIT is enjoyable and has high unsupervised adherence rates in overweight and obese adults. However, HIIT may be associated with an increase in inflammation with short-term exercise in this population.

Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance

Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R) or non-responders (NRs), especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT) and the prevalence of NRs in adult women with higher and lower levels of insulin resistance. Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m²; n = 20) and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m²; n = 20). Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training. Results: There were significant training-induced changes [delta percent (Δ%)] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) scores in the H-IR group (-8.8, -26.5, -32.1%, p < 0.0001), whereas no significant changes were observed in the L-IR. Both groups showed significant pre-post changes in other anthropometric variables [waist circumference (-5.2, p < 0.010, and -3.8%, p = 0.046) and tricipital (-13.3, p < 0.010, and -13.6%, p < 0.0001), supra-iliac (-19.4, p < 0.0001, and -13.6%, p < 0.0001), and abdominal (-18.2, p < 0.0001, and -15.6%, p < 0.010) skinfold measurements]. Systolic blood pressure decreased significantly only in the L-IR group (-3.2%, p < 0.010). Both groups showed significant increases in 1RM_LE (+12.9, p < 0.010, and +14.7%, p = 0.045). There were significant differences in the prevalence of NRs between the H-IR and L-IR groups for fasting glucose (25 vs. 95%, p < 0.0001) and fasting insulin (p = 0.025) but not for HOMA-IR (25 vs. 45%, p = 0.185). Conclusion: Independent of the "magnitude" of the cardiometabolic disease (i.e., higher vs. lower insulin resistance), no differences were observed in the NRs prevalence with regard to improved HOMA-IR or to anthropometric, cardiovascular, and muscle performance co-variables after 10 weeks of HIIT in sedentary adult women. This research demonstrates the protective effect of HIIT against cardiometabolic disease progression in a sedentary population.

Effects of 6-Weeks High-Intensity Interval Training in Schoolchildren with Insulin Resistance: Influence of Biological Maturation on Metabolic, Body Composition, Cardiovascular and Performance Non-responses

Background: Previous studies have observed significant heterogeneity in the magnitude of change in measures of metabolic response to exercise training. There are a lack of studies examining the prevalence of non-responders (NRs) in children while considering other potential environmental factors involved such as biological maturation. Aim: To compare the effects and prevalence of NRs to improve the insulin resistance level (by HOMA-IR), as well as to other anthropometric, cardiovascular, and performance co-variables, between early (EM) and normal maturation (NM) in insulin-resistance schoolchildren after 6-weeks of HIIT. Methods: Sedentary children (age 11.4 ± 1.7 years) were randomized to either HIIT-EM group (n = 12) or HIIT-NM group (n = 17). Fasting glucose (FGL), fasting insulin (FINS) and homeostasis model assessment of insulin resistant (HOMA-IR) were assessed as the main outcomes, as well as the body composition [body mass, body mass index (BMI), waist circumference (WC), and tricipital (TSF), suprailiac (SSF) and abdominal skinfold (AbdSF)], cardiovascular systolic (SBP) and diastolic blood pressure (DBP), and muscular performance [one-repetition maximum strength leg-extension (1RMLE) and upper row (1RMUR) tests] co-variables were assessed before and after intervention. Responders or NRs to training were defined as a change in the typical error method from baseline to follow-up for the main outcomes and co-variables. Results: There were no significant differences between groups in the prevalence of NRs based on FGL, FINS, and HOMA-IR. There were significant differences in NRs prevalence to decrease co-variables body mass (HIIT-EM 66.6% vs. HIIT-NM 35.2%) and SBP (HIIT-EM 41.6% vs. HIIT-NM 70.5%). A high risk [based on odds ratios (OR)] of NRs cases was detected for FGL, OR = 3.2 (0.2 to 5.6), and HOMA-IR, OR = 3.2 (0.2 to 6.0). Additionally, both HIIT-EM and HIIT-NM groups showed significant decreases (P < 0.05) in TSF, SSF, and AbdSF skinfold, and similar decreases in fasting insulin and HOMA-IR. The HIIT-EM group showed significant decreases in SBP. The HIIT-NM group showed significant increases in 1RMLE and 1RMUR. A large effect size was observed for pre-post changes in TSF in both groups, as well as in SSF in the HIIT-NM group. Conclusion: Although there were no differences in the prevalence of NRs to metabolic variables between groups of insulin resistance schoolchildren of different maturation starting, other NRs differences were found to body mass and systolic BP, suggesting that anthropometric and cardiovascular parameters can be playing a role in the NRs prevalence after HIIT. These results were displayed with several metabolic, body composition, blood pressure, and performance improvements independent of an early/normal maturation or the prevalence of NRs.

Effects and prevalence of nonresponders after 12 weeks of high-intensity interval or resistance training in women with insulin resistance: a randomized trial

Our aim was to investigate the effects and prevalence of nonresponders (NR) to high-intensity interval training (HIIT) and resistance training (RT) in women with insulin resistance on cardiometabolic health parameters. Sedentary overweight/obese insulin-resistant women (age = 33.5 ± 6.5 yr; body mass index = 29.9 ± 3.7 kg/m2) were randomly assigned to a triweekly HIIT program (HIIT; n = 18) or resistance training (RT; n = 17). Anthropometry (body mass, fat mass, muscle mass, waist circumference, and skinfold thickness), cardiovascular (blood pressure), metabolic [fasting glucose, fasting insulin, and homeostatic model of insulin resistance (HOMA-IR)], as well as muscle strength, and endurance performance covariables were measured before and after 12 wk in both intervention groups. The interindividual variability to exercise training of the subjects was categorized as responders and NR using as cut points two times the typical error of measurement in mean outcomes. After intervention, significant reduction in waist circumference, skinfold thicknesses, fat mass, blood pressure, fasting glucose, insulin, and HOMA-IR ( P < 0.05) were identified to HIIT and RT group, respectively. Both HIIT and RT groups exhibited a significant decrease in the endurance performance, whereas only RT exhibited increased muscle strength. Significant differences in the NR prevalence between the HIIT and RT groups were identified for a decrease in fat mass (HIIT 33.3% vs. RT 70.5%; P = 0.028), muscle mass (HIIT 100% vs. RT 52.9%; P = 0.001), and tricipital skinfold (HIIT 5.5% vs. RT 29.4%; P < 0.041). For diastolic blood pressure, significant differences were observed in the NR prevalence between the HIIT and RT groups (55.5% vs. 94.1; P = 0.009). However, there were no differences in the NR prevalence between HIIT and RT for decreasing fasting glucose. Twelve weeks of HIIT and RT have similar effects and NR prevalence to improve glucose control variables; however, there is different NR prevalence in other anthropometric, cardiovascular, strength, and endurance performance measurements in insulin-resistant women. These findings were displayed with a similar time investment per week of 114 vs. 108 min, respectively, to HIIT and RT.

NEW & NOTEWORTHY The effects and prevalence of nonresponders (NR) to improve glucose control variables have predominately been reported by endurance training. A uniqueness of the present study was to examine the NR prevalence in women with insulin resistance after high-intensity interval (HIIT) and resistance training (RT). This study demonstrates that 12 wk of HIIT and RT have similar effects and NR prevalence to improve glucose control variables. However, significantly different NR prevalence were observed in other anthropometric, cardiovascular, strength, and endurance performance measurements.

Exercise as medicine - evidence for prescribing exercise as therapy in 26 different chronic diseases

This review provides the reader with the up-to-date evidence-based basis for prescribing exercise as medicine in the treatment of 26 different diseases: psychiatric diseases (depression, anxiety, stress, schizophrenia); neurological diseases (dementia, Parkinson's disease, multiple sclerosis); metabolic diseases (obesity, hyperlipidemia, metabolic syndrome, polycystic ovarian syndrome, type 2 diabetes, type 1 diabetes); cardiovascular diseases (hypertension, coronary heart disease, heart failure, cerebral apoplexy, and claudication intermittent); pulmonary diseases (chronic obstructive pulmonary disease, asthma, cystic fibrosis); musculo-skeletal disorders (osteoarthritis, osteoporosis, back pain, rheumatoid arthritis); and cancer. The effect of exercise therapy on disease pathogenesis and symptoms are given and the possible mechanisms of action are discussed. We have interpreted the scientific literature and for each disease, we provide the reader with our best advice regarding the optimal type and dose for prescription of exercise.

Personalised Prescription of Scalable High Intensity Interval Training to Inactive Female Adults of Different Ages

Stepping is a convenient form of scalable high-intensity interval training (HIIT) that may lead to health benefits. However, the accurate personalised prescription of stepping is hampered by a lack of evidence on optimal stepping cadences and step heights for various populations. This study examined the acute physiological responses to stepping exercise at various heights and cadences in young (n = 14) and middle-aged (n = 14) females in order to develop an equation that facilitates prescription of stepping at targeted intensities. Participants completed a step test protocol consisting of randomised three-minute bouts at different step cadences (80, 90, 100, 110 steps·min^-1) and step heights (17, 25, 30, 34 cm). Aerobic demand and heart rate values were measured throughout. Resting metabolic rate was measured in order to develop female specific metabolic equivalents (METs) for stepping. Results revealed significant differences between age groups for METs and heart rate reserve, and within-group differences for METs, heart rate, and metabolic cost, at different step heights and cadences. At a given step height and cadence, middle-aged females were required to work at an intensity on average 1.9 ± 0.26 METs greater than the younger females. A prescriptive equation was developed to assess energy cost in METs using multilevel regression analysis with factors of step height, step cadence and age. Considering recent evidence supporting accumulated bouts of HIIT exercise for health benefits, this equation, which allows HIIT to be personally prescribed to inactive and sedentary women, has potential impact as a public health exercise prescription tool.