Short-term high-calorie high-fat feeding induces hyperinsulinemia and blunts skeletal muscle microvascular blood flow in healthy humans.

Skeletal muscle microvascular blood flow (MBF) plays an important role in glucose disposal in muscle. Impairments in muscle MBF contribute to insulin resistance and prediabetes. Animal studies show that short-term (3 day) high-fat feeding blunts skeletal muscle MBF before impairing insulin-stimulated glucose disposal. It is not known whether this occurs in humans. We investigated the temporal impact of a 7-day high-calorie high-fat (HCHF) diet intervention (+52% kJ; 41% fat) on fasting and postprandial cardiometabolic outcomes in 14 healthy adults (18-37 yr). Metabolic health and vascular responses to a mixed-meal challenge (MMC) were measured at pre (day 0)-, mid (day 4)- and post (day 8)-intervention. There were no significant differences in body weight, body fat %, fasting blood glucose, and fasting plasma insulin concentrations at pre-, mid- and postintervention. Compared with preintervention there was a significant increase in insulin (but not glucose) total area under the curve in response to the MMC at midintervention (P = 0.041) and at postintervention (P = 0.028). Unlike at pre- and midintervention, at postintervention muscle MBF decreased at 60 min (P = 0.024) and 120 min (P = 0.023) after the MMC. However, macrovascular blood flow was significantly increased from 0 to 60 min (P < 0.001) and 120 min (P < 0.001) after the MMC at pre-, mid- and postintervention. Therefore, short-term HCHF feeding in healthy individuals leads to elevated postprandial insulin but not glucose levels and a blunting of meal-induced skeletal muscle MBF responses but not macrovascular blood flow responses.NEW & NOTEWORTHY This is the first study to investigate skeletal muscle microvascular blood flow (MBF) responses in humans after short-term high-calorie high-fat (HCHF) diet. The main findings were that HCHF diet causes elevated postprandial insulin in healthy individuals within 3 days and blunts meal-induced muscle MBF within 7 days, despite no impairments in postprandial glucose or macrovascular blood flow.

Acute Effects of Resistance Exercise on Intraocular Pressure in Healthy Adults: A Systematic Review.

ABSTRACT: Hackett, DA, Li, J, Wang, B, Way, KL, Cross, T, and Tran, DL. Acute effects of resistance exercise on intraocular pressure in healthy adults: A systematic review. J Strength Cond Res 38(2): 394-404, 2024-Intraocular pressure (IOP) tends to fluctuate during a resistance exercise (RE). This systematic review examines the acute effects of RE on IOP in healthy adults and factors that influence changes in IOP. Five electronic databases were searched using terms related to RE and IOP. A strict inclusion criterion was applied, which included being 55 years or younger with no medical conditions and RE intensity needing to be quantifiable (e.g., based on a maximal effort). Thirty-four studies met the inclusion criteria for this review. Isometric and isotonic contractions produced similar changes in IOP during RE up to 28.7 mm Hg. Exercises that involved larger muscle mass, such as squats and leg press, were found to produce changes in IOP during exercise ranging from 3.1 to 28.7 mm Hg. Smaller changes in IOP during RE were found for exercises engaging less muscle mass (e.g., handgrip and bicep curls). Intraocular pressure was found to increase during RE when lifting heavier loads and with longer exercise durations (e.g., greater repetitions). The Valsalva maneuver (VM) and breath-hold during RE accentuated the change in IOP, with more extreme changes observed with the VM. However, most studies showed that postexercise IOP returned to baseline after approximately 1 minute of recovery. An acute increase in IOP is observed during RE in healthy adults with fluctuations of varying magnitude. Factors that independently increase IOP during RE include exercises involving larger muscle mass, heavy loads, greater set duration, and when the VM or breath-hold is performed.

Sex-specific associations of fat mass and muscle mass with cardiovascular disease risk factors in adults with type 2 diabetes living with overweight and obesity: secondary analysis of the Look AHEAD trial.

BACKGROUND: Distinguishable sex differences exist in fat mass and muscle mass. High fat mass and low muscle mass are independently associated with cardiovascular disease (CVD) risk factors in people living with type 2 diabetes; however, it is unknown if the association between fat mass and CVD risk is modified by muscle mass, or vice versa. This study examined the sex-specific interplay between fat mass and muscle mass on CVD risk factors in adults with type 2 diabetes living with overweight and obesity. METHODS: Dual-energy X-ray absorptiometry (DXA) measures were used to compute fat mass index (FMI) and appendicular muscle mass index (ASMI), and participants were separated into high-fat mass vs. low-fat mass and high-muscle mass vs. low-muscle mass. A two-way analysis of covariance (ANCOVA: high-FMI vs. low-FMI by high-ASMI vs. low-ASMI) was performed on CVD risk factors (i.e., hemoglobin A1C [A1C]; high-density lipoprotein cholesterol; low-density lipoprotein cholesterol; triglycerides; systolic and diastolic blood pressure; cardiorespiratory fitness, depression and health related-quality of life [HR-QoL]) at baseline and following a 1-year intensive lifestyle intervention (ILI) for females and males separately, with a primary focus on the fat mass by muscle mass interaction effects. RESULTS: Data from 1,369 participants (62.7% females) who completed baseline DXA were analyzed. In females, there was a fat mass by muscle mass interaction effect on A1C (p = 0.016) at baseline. Post-hoc analysis showed that, in the low-FMI group, A1C was significantly higher in low-ASMI when compared to high-ASMI (60.3 ± 14.1 vs. 55.5 ± 13.5 mmol/mol, p = 0.023). In the high-FMI group, there was no difference between high-ASMI and low-ASMI (56.4 ± 12.5 vs. 56.5 ± 12.8 mmol/mol, p = 0.610). In males, only high-FMI was associated with higher A1C when compared to low-FMI (57.1 ± 14.4 vs. 54.2 ± 12.0 mmol/mol, p = 0.008) at baseline. Following ILI, there were significant fat mass by muscle mass interaction effects on changes in the mental component of HR-QoL in males. CONCLUSION: Considering that A1C predicts future CVD, strategies to lower A1C may be especially important in females with low fat and low muscle mass living with type 2 diabetes. Our results highlight the complicated and sex-specific contribution of fat mass and muscle mass to CVD risk factors.

Degree of adiposity and obesity severity is associated with cutaneous microvascular dysfunction in type 2 diabetes.

BACKGROUNDS AND AIMS: Obesity and diabetes independently contribute to cutaneous microvascular dysfunction via pathological processes that are not fully understood. We sought to determine if obesity severity is associated with cutaneous microvascular dysfunction and measures of peripheral arterial disease in adults with type 2 diabetes in cross-sectional observational study design. METHODS AND RESULTS: Primary outcomes were post-occlusive reactive hyperaemia as determined by laser-Doppler fluxmetry (peak flux post-occlusion, time to peak flux post-occlusion, peak as a percentage of baseline, and area under the curve [AuC] index post-occlusion to pre-occlusion). Secondary outcomes were ankle- and toe-brachial indices (ABI and TBI) and systolic toe pressure. Thirty-six participants (20 men, 16 women) with mean age 55 ± 8 years, BMI of 36 ± 5 kg/m2 and duration of diabetes 8 ± 6 years underwent measurements. After adjusting for age and duration of diabetes, SAT and total percentage body fat were able to explain 29% (p = 0.001) and 20% (p = 0.01) of variance of AuC index models, as well as 29% (p = 0.02) and 18% (p = 0.02) of peak as a percentage of baseline models, respectively. Though TBI demonstrated moderate, significant correlations with SAT (r:0.37, p = 0.04) and total percentage body fat (r:0.39, p = 0.03), these were not upheld by regression analyses. Neither ABI nor systolic toe pressure significantly correlated with any measure of adiposity or obesity. CONCLUSION: These findings demonstrate impairment in cutaneous microvascular function related to adiposity and obesity severity in adults with type 2 diabetes, suggesting that obesity may pathologically effect cutaneous microvascular function in the absence of overt macrovascular disease, warranting further investigation.

Meeting the Canadian strength training recommendations: Implications for the cardiometabolic, psychological and musculoskeletal health of nurses.

AIM: To examine the proportion of nurses meeting the strength training recommendation and its associated cardiometabolic, psychological and musculoskeletal benefits. BACKGROUND: Strength training targets poor physical and mental health often reported by nurses; however, it is unknown whether nurses are meeting the strength training guidelines. METHODS: Nurses from 14 hospitals completed a 7-day physical activity log. Nurses were considered meeting the recommendation if they reported ≥2 strength training sessions per week. Cardiometabolic, psychological and musculoskeletal health, and levels of motivation were compared between nurses meeting and not meeting the guidelines. RESULTS: Of the 307 nurses (94% female; age: 43 ± 12 years), 29 (9.4%) met the strength training recommendation. These nurses had lower body mass index (24.1 ± 2.6 vs. 27.3 ± 5.5 kg/m2 , p = .007) and waist circumference (73.8 ± 8.3 vs. 81.1 ± 11.7 cm, p = .017); and higher vigour-activity (18.0 ± 5.8 vs. 15.6 ± 6.5 points, p = .046) and self-determined motivation (relative autonomic index: 54.9 ± 20.3 vs. 45.0 ± 23.8 points, p = .042) scores than nurses not meeting the recommendation. CONCLUSION: While the proportion of nurses meeting the strength training recommendation was small (<10%), they had lower body mass and waist circumference, and higher vigour-activity. IMPLICATIONS FOR NURSING MANAGEMENT: Strategies to increase the strength training engagement may improve the cardiometabolic health and increase vigour among nurses.

Effect of resistance training on liver fat and visceral adiposity in adults with obesity: A randomized controlled trial.

AIM: Regular aerobic exercise reduces visceral adipose tissue (VAT) and liver fat, however, not all individuals are able to adopt and adhere to such programs. Progressive resistance training (PRT) may be an alternative therapy, but there is limited available evidence. We examined the efficacy of PRT as per current exercise guidelines, compared with sham exercise placebo on liver fat and VAT. METHODS: Twenty-nine inactive and overweight/obese (body mass index ≥25 kg/m2 ) adults (age 29-59) were randomized to receive 8 weeks of PRT (n = 15, 10 exercises per session, 8-12 repetitions, 2-3 sets per exercise at 80-85% of one-repetition maximum, 3 days per week) or a sham exercise placebo control (CON) (n = 14). Change in liver fat, VAT, and abdominal s.c. adipose tissue (SAT) were assessed by magnetic resonance spectroscopy and imaging). RESULTS: There were no significant group by time interactions for change in liver fat in PRT versus CON groups (-0.07 ± 0.31% vs. 0.55 ± 0.77%, respectively, P = 0.19), VAT (-175 ± 85 cm3 vs. 10 ± 64 cm3 , respectively, P = 0.11), or abdominal SAT (-436 ± 245 cm3 vs. 127.29 ± 182 cm3 , respectively, P = 0.10) despite a significant increase in muscle volume (55 ± 78 cm3 vs. -0.04 ± 8 cm3 , respectively, P = 0.03). CONCLUSION: Traditional PRT is not effective for reducing liver fat in overweight/obese adults compared with placebo control. Although PRT has known metabolic benefits, an adequate volume of aerobic exercise should be promoted if liver fat is the therapeutic target.

Effects of Age and Playing Position on Field-Based Physical Fitness Measures in Adolescent Female Netball Players.

This cross-sectional study investigated the impact of age and playing position, controlling for maturity, on physical fitness indicators in 303 adolescent female netball players aged 12.0 to 15.9 years. Assessments included estimated maximal oxygen uptake (VO2max) via the 20 m shuttle run test, 10 m and 20 m sprints, change of direction speed (CODS) using the 505 test, and muscle power via the medicine ball chest throw (MBCT) and countermovement vertical jump (CMJ). Participants were grouped by age (12 to 15 years) and playing position (non-circle and circle players), with age at peak height velocity as a covariate for maturity. Results revealed that, at 15 years, CMJ height was greater than at 12 years and 13 years (p < 0.05, partial η2 = 0.048). MBCT distance increased across age groups (p < 0.01, partial η2 = 0.323). Age had no impact on sprints, VO2max, or CODS. Non-circle players outperformed circle players in the 10 m sprint (p = 0.042, partial η2 = 0.016) and 20 m sprints (p = 0.010, partial η2 = 0.025) and displayed higher VO2max (p < 0.001, partial η2 = 0.036). Circle players were taller (p = 0.046, partial η2 = 0.014) and heavier (p < 0.001, partial η2 = 0.040) than non-circle players. Playing positions showed no differences in CMJ and MBCT. In adolescent female netball players, only muscle power is influenced by age, while non-circle players exhibit superior aerobic fitness and speed compared to circle players. Coaches may be able to utilize the distinct age and playing position traits of adolescent netballers to inform player selection and design targeted training programs.

Effects of interval training in cardiovascular disease populations: a clinical perspective.

Nearly 20 years have elapsed since the first clinical trial investigated the impact of interval training on patients with cardiovascular disease (CVD). This clinical corner discusses the health outcomes of systematic reviews and meta-analyses and appropriately powered randomized clinical trials which have tested these interval training programs across various CVDs (i.e., coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, and cardiac implantable electronic devices). The publications included in this clinical corner have shown that interval training leads to similar or superior improvements in peak oxygen uptake (V̇O2peak), functional capacity, pain free walking, quality of life, anxiety, depression, and endothelial function, but the magnitude of improvements across varying protocols (e.g., length and number of work periods, intensities of work periods, duration of exercise sessions, frequency of exercise sessions, and duration of program) and optimal dosage for males and females are unclear across CVD conditions. The heterogeneity in protocols, physical and mental health outcome measures, and lack of sex- and gender-based analyses calls for more high-quality research in this area.

Sex Differences in Physical Activity Levels and Sitting Time in Patients With Atrial Fibrillation.

PURPOSE: While research demonstrates low levels of physical activity (PA) among adults living with atrial fibrillation (AF), there is limited evidence investigating sex differences in moderate to vigorous intensity physical activity (MVPA) and sedentary time in this population. The primary aim was to examine sex differences in MVPA levels and sitting time between women and men with AF. Secondary aims explored sex differences in sociodemographic factors, outcome expectations, and task self-efficacy toward PA levels. METHODS: This was a subanalysis of the CHAMPLAIN-AF cohort study. Women and men with AF completed a survey, including the Short-Form International Physical Activity Questionnaire. RESULTS: A total of 210 women (median = 66.0 yr: 95% CI, 63.5-68.0) and 409 men (median = 66.0 yr: 95% CI, 64.0-67.0) were included. No sex differences were observed in median weekly MVPA (60 min/wk: 95% CI, 0-120 in women vs 120 min/wk: 95% CI, 85-150 in men) and daily sitting time (5.5 hr/d: 95% CI, 5.0-6.0 in women vs 6.0 hr/d: 95% CI, 5.0-6.0 in men). Women engaged in significantly less vigorous-intensity PA than men ( P = .03) and demonstrated significantly lower task self-efficacy ( P < .01). Significant positive correlations in PA levels with outcome expectations (mostly weak) and task self-efficacy (mostly strong) were observed in both sexes. CONCLUSION: Most women and men with AF did not meet the global MVPA guidelines but met the sitting time recommendation. Women presented with lower vigorous-intensity physical activity levels and confidence than men. Strategies to increase physical activity behavior, considering sociodemographic factors and task self-efficacy, are needed and may differ between sexes.

Effect of resistance training on local muscle endurance in middle-aged and older adults: A systematic review with meta-analysis and meta-regression.

BACKGROUND: Local muscle endurance (LME) is a significant indicator of muscle health and function in middle-aged and older adults. However, resistance training (RT) practices which optimise performance in this population are currently unclear. This study examined: 1) the effect of RT on LME; and 2) the impact of acute resistance exercise program variables on LME in middle-aged and older adults. METHODS: Five electronic databases were searched using terms related to RT, LME, and older adults. Random effects (Hedges' g) meta-analyses were undertaken to estimate the effect of RT on upper and lower body LME assessed via maximal repetitions during an isotonic test. The impact of resistance exercise program variables on LME effects was explored using meta-regression analyses. RESULTS: Fifteen studies met the inclusion criteria for this review. Upon sensitivity analysis, one study was removed. Large effects favoured RT for LME of the upper body (g = 1.10, p < 0.001) and lower body (g = 1.18, p < 0.001). Large effects on LME from RT were found irrespective of training intensity or other resistance exercise program variables. Moderate heterogeneity and publication bias were found in most analyses. DISCUSSION: RT is an effective means for improving LME in middle-aged and older adults. Optimal training characteristics have not been defined by this review, as improvement in LME was unrelated to RT volume or loading intensity. Caution is warranted when interpreting the findings due to heterogeneity and bias present in existing literature. Additional studies are needed with direct comparisons of various training techniques.

Cluster Sets to Prescribe Interval Resistance Training: A Potential Method to Optimise Resistance Training Safety, Feasibility and Efficacy in Cardiac Patients.

The integration of resistance training for cardiac patients leads to important health outcomes that are not optimally obtained with aerobic exercise; these include an increase in muscle mass, maintenance of bone mineral density, and improvements in muscular fitness parameters. Despite the proliferation of evidence supporting resistance exercise in recent decades, the implementation of resistance training is underutilised, and prescription is often sub-optimal in cardiac patients. This is frequently associated with safety concerns and inadequate methods of practical exercise prescription. This review discusses the potential application of cluster sets to prescribe interval resistance training in cardiac populations. The addition of planned, regular passive intra-set rest periods (cluster sets) in resistance training (i.e., interval resistance training) may be a practical solution for reducing the magnitude of haemodynamic responses observed with traditional resistance training. This interval resistance training approach may be a more suitable option for cardiac patients. Additionally, many cardiac patients present with impaired exercise tolerance; this model of interval resistance training may be a more suitable option to reduce fatigue, increase patient tolerance and enhance performance to these workloads. Practical strategies to implement interval resistance training for cardiac patients are also discussed. Preliminary evidence suggests that interval resistance training may lead to safer acute haemodynamic responses in cardiac patients. Future research is needed to determine the efficacy and feasibility of interval resistance training for health outcomes in this population.

Effect of High-Intensity Interval Training in Patients With Atrial Fibrillation: A Randomized Clinical Trial.

Importance: Patients with atrial fibrillation (AF) experience poor functional capacity and quality of life (QOL). High-intensity interval training (HIIT) has been shown to elicit greater improvements in functional capacity and QOL compared with moderate to vigorous intensity continuous training (MICT) in other cardiovascular populations, yet HIIT remains understudied in AF. Objective: To compare the effects of 12 weeks of HIIT and MICT-based cardiovascular rehabilitation (CR) on functional capacity and general QOL in patients with persistent and permanent AF. Disease-specific QOL, resting heart rate (HR), time in AF, and physical activity (PA) levels were also assessed. Design, Setting, and Participants: This randomized clinical trial, conducted between November 17, 2015, and February 4, 2020, at a tertiary-care cardiovascular health center in Ottawa, Canada, recruited 94 patients with persistent and permanent AF. Interventions: High-intensity interval training (23 minutes: two 8-minute interval training blocks of 30-second work periods at 80%-100% of peak power output interspersed with 30-second recovery) or CR (60 minutes: continuous aerobic conditioning within 67%-95% of peak HR and 12-16 of 20 ratings of perceived exertion) twice weekly for 12 weeks. Main Outcomes and Measures: The primary outcomes were changes in functional capacity (6-minute walk test [6MWT] distance) and general QOL (Short Form 36) from baseline to 12 weeks' follow-up. Secondary outcomes included changes in disease-specific QOL (Atrial Fibrillation Severity Scale), resting HR, time in AF, and PA levels. An intention-to-treat analysis was used to compare changes between groups. Results: Of the 94 patients who consented, 86 participated (mean [SD] age, 69 [7] years; 57 [66.3%] men). No significant differences in improvements in 6MWT distance (mean [SD], 21.3 [34.1] vs 13.2 [55.2] m; P = .42) and general QOL (Physical Component Summary, 0.5 [6.1] vs 1.1 [4.9] points; P = .87) between HIIT and CR were observed. No significant differences in improvements in disease-specific QOL (AF symptoms: -1.7 [4.3] vs -1.5 [4] points, P = .59), resting HR (-3.6 [10.6] vs -2.9 [12.4] beats per minute, P = .63), and moderate to vigorous PA levels (37.3 [93.4] vs 14.4 [125.7] min/wk; P = .35) between HIIT and CR were detected. Participants attended a mean (SD) of 18.3 (6.1) (75.1%) HIIT sessions and 20.0 (4.5) (83.4%) CR sessions (P = .36). Conclusions and Relevance: In this randomized clinical trial, twice-weekly 23-minute HIIT was as efficacious as twice-weekly 60-minute CR in improving functional capacity, general and disease-specific QOL, resting HR, and PA levels in patients with persistent and permanent AF. Trial Registration: ClinicalTrials.gov Identifier: NCT02602457.

The Physical Activity Levels and Sitting Time of Adults Living With Atrial Fibrillation: The CHAMPLAIN-AF Study.

Background: The primary goal of this study was to determine the time spent completing moderate-to-vigorous intensity physical activity (MVPA) among adults with atrial fibrillation (AF). Secondary aims examined MVPA and sitting time (ST) by AF subtypes (ie, paroxysmal, persistent, long-standing persistent, and permanent) and associations between MVPA or ST and knowledge, task self-efficacy, and outcome expectations. Methods: An observational study was conducted in the Champlain region of Ontario, Canada. AF patients completed a survey to determine MVPA and ST using the Short-Form International Physical Activity Questionnaire. Results: A total of 619 patients (66% male; median age 65 years [95% CI 64-67 years]) completed the survey. Median MVPA and ST were 100 (60-120) min/wk and 6 (5-6) h/d; 56% of patients were not meeting the Canadian 24H Movement Guidelines. Most patients (54%) did not know/were unsure of the MVPA recommendations, yet 72% thought physical activity should be part of AF management. Positive correlations were found between higher MVPA levels and the following: (i) speaking to a healthcare professional about engaging in physical activity for managing AF (ρ = 0.108, P = 0.017); (ii) greater confidence regarding ability to perform physical activity and muscle-strengthening exercise (ρ = 0.421, P < 0.01); and (iii) patient agreement that AF would be better managed if they were active (ρ = 0.205, P < 0.01). Conclusions: Many AF patients do not meet the MVPA recommendations, which may be due to lack of physical activity knowledge. Exercise professionals may help educate patients on the benefits of physical activity, improve task-self efficacy, and integrate MVPA into patient lifestyles.

Introduction: Le principal objectif de la présente étude était de déterminer le temps consacré à faire de l'activité physique modérée à vigoureuse (APMV) chez les adultes atteints de fibrillation auriculaire (FA). Les objectifs secondaires visaient à examiner l'APMV et le temps en position assise (TA) selon les sous-types de FA (c.-à-d. paroxystique, persistante, persistante de longue durée et permanente) et les associations entre l'APMV ou le TA et les connaissances, le sentiment d'auto-efficacité et les attentes de résultats. Méthodes: Nous avons réalisé une étude observationnelle dans la région de Champlain, en Ontario, au Canada. Les patients atteints de FA ont rempli une enquête pour déterminer l'APMV et le TA à l'aide du questionnaire court International Physical Activity Questionnaire (IPAQ). Résultats: Un total de 619 patients (66 % d'hommes; âge médian de 65 ans [IC à 95 % 64-67 ans]) a rempli l'enquête. L'APMV et le TPA médians étaient de 100 (60-120) min/sem et de 6 (5-6) h/j; 56 % des patients ne répondaient pas aux Directives canadiennes en matière de mouvement sur 24 heures. La plupart des patients (54 %) ne connaissaient pas les recommandations d'APMV ou n'étaient pas certains de les connaître, mais 72 % pensaient que l'activité physique devrait faire partie de la prise en charge de la FA. Nous avons observé des corrélations positives entre les degrés plus élevés d'APMV et ce qui suit : (i) le fait de parler à un professionnel de la santé de la pratique de l'activité physique pour prendre en charge la FA (ρ = 0,108, P = 0,017); (ii) la confiance accrue quant à la capacité de faire de l'activité physique et les exercices de renforcement musculaire (ρ = 0,421, P < 0,01); (iii) l'accord du patient sur le fait que la pratique de l'activité physique contribuerait à une meilleure prise en charge de la FA (ρ = 0,205, P < 0,01). Conclusions: Plusieurs patients atteints de FA ne répondaient pas aux recommandations d'APMV, possiblement en raison du manque de connaissances concernant l'activité physique. Les professionnels de l'activité physique peuvent contribuer à l'éducation des patients afin de leur faire connaître les avantages de l'activité physique, améliorer leur auto-efficacité et intégrer l'APMV à leur mode de vie.

The effect of acute aerobic exercise on central arterial stiffness, wave reflections, and hemodynamics in adults with diabetes: A randomized cross-over design.

BACKGROUND: Individuals with diabetes have greater central arterial stiffness, wave reflections, and hemodynamics, all of which promote the accelerated cardiovascular pathology seen in this population. Acute aerobic exercise has been shown to be an effective strategy for reducing central arterial stiffness, wave reflections, and hemodynamics in healthy individuals; however, the effects of acute aerobic exercise in reducing these outcomes is not well established in people with diabetes. Recently, implementation of high-intensity interval exercise (HIIE) has shown superior improvements in cardiovascular health outcomes when compared to traditional aerobic exercise. Yet, the effect of HIIE on the aforementioned outcomes in people with diabetes is not known. The purpose of this study was to (i) describe the central arterial stiffness, wave reflections, and hemodynamic responses to a bout of HIIE and moderate-intensity continuous exercise (MICE) in adults with diabetes; and (ii) compare the effects of HIIE and MICE on the aforementioned outcomes. METHODS: A total of 24 adult men and women (aged 29-59 years old) with type 1 (n = 12) and type 2 (n = 12) diabetes participated in a randomized cross-over study. All participants completed the following protocols: (i) HIIE: cycling for 4 × 4 min at 85%-95% of heart rate peak (HRpeak), interspersed with 3 min of active recovery at 60%-70%HRpeak; (ii) MICE: 33 min of continuous cycling at 60%-70%HRpeak; and (iii) control (CON): lying quietly in a supine position for 30 min. RESULTS: A significant group × time effect was found for changes in central systolic blood pressure (F = 3.20, p = 0.01) with a transient reduction for the HIIE group but not for the MICE or CON groups. There was a significant group × time effect for changes in augmentation index at a heart rate of 75 beats/min (F = 2.32, p = 0.04) with a decrease following for HIIE and MICE but not for CON. For all other measures of central arterial stiffness and hemodynamics, no significant changes were observed (p > 0.05). CONCLUSION: A bout of HIIE appears to lead to a greater transient reduction in central systolic blood pressure than the reduction observed following MICE; however, both HIIE and MICE improved augmentation index at a heart rate of 75 beats/min in people with diabetes. There was no significant difference in response to HIIE and MICE in all outcomes. This provides preliminary evidence on the role of HIIE on such outcomes in people with diabetes.

The association between cardiorespiratory fitness, liver fat and insulin resistance in adults with or without type 2 diabetes: a cross-sectional analysis

BACKGROUND: Exercise-induced improvements in cardiorespiratory fitness (CRF) often coincide with improvements in insulin sensitivity and reductions in liver fat content. However, there are limited data concerning the relationship between CRF and liver fat content in adults with varying degrees of metabolic dysfunction. METHODS: The aim of this study was to examine the association between CRF, liver fat content, and insulin resistance in inactive adults with obesity and with or without type 2 diabetes (T2D), via cross-sectional analysis. CRF was determined via a graded exercise test. Liver fat content was assessed via proton magnetic resonance spectroscopy and insulin resistance was assessed via homeostatic model of insulin resistance (HOMA-IR). A partial correlation analysis, controlling for age and gender, was performed to determine the association between CRF, demographic, cardiometabolic, and anthropometric variables. Independent t tests were performed to compare cardiometabolic outcomes between participants with T2D and participants without T2D. RESULTS: Seventy-two adults (46% male) with a mean age of 49.28 ± 10.8 years, BMI of 34.69 ± 4.87 kg/m2, liver fat content of 8.37 ± 6.90%, HOMA-IR of 3.07 ± 2.33 and CRF of 21.52 ± 3.77 mL/kg/min participated in this study. CRF was inversely associated with liver fat content (r = - 0.28, p = 0.019) and HOMA-IR (r = - 0.40, p < 0.001). Participants with T2D had significantly higher liver fat content (+ 3.66%, p = 0.024) and HOMA-IR (+ 2.44, p < 0.001) than participants without T2D. Participants with T2D tended to have lower CRF than participants without T2D (- 1.5 ml/kg/min, p = 0.094). CONCLUSION: CRF was inversely associated with liver fat content and insulin resistance. Participants with T2D had lower CRF than those without T2D, however, the difference was not statistically significant. Further longitudinal studies are required to elucidate the relationship between CRF and the progression of obesity-related diseases such as T2D. Registration: ACTRN12614001220651 (retrospectively registered on the 19th November 2014) and ACTRN12614000723684 (prospectively registered on the 8th July 2014).

Sex differences in physical and mental health following high-intensity interval training in adults with cardiovascular disease who completed cardiac rehabilitation.

This pre-post study examined sex-differences in peak aerobic power (V̇O2peak) and physical- and mental-health outcomes in adults with cardiovascular disease who completed high-intensity interval training (HIIT)-based cardiac rehabilitation. HIIT consisted of 25 minutes of alternating higher- (4×4 minutes 85-95% heart rate peak (HRpeak)) and lower- (3×3 minutes 60-70% HRpeak) intensity intervals twice weekly for 10 weeks. V̇O2peak estimated from a graded exercise test using the American College of Sports Medicine equation, body mass index (BMI), waist circumference, blood pressure, blood biomarkers and anxiety and depression were assessed at baseline and follow-up. Linear mixed-effects models for repeated measures were performed to examine differences over time between sexes. Of 140 participants (mean ± standard deviation: 58 ± 9 years), 40 were female. Improvements in V̇O2peak did not differ between sexes (interaction: p = 0.273, females: 28.4 ± 6.4 to 30.9 ± 7.6; males: 34.3 ± 6.3 to 37.4 ± 6.0 mL/kg/min). None of the time by sex interactions were significant. Significant main effects of time showed reductions in waist circumference, triglycerides, low-density lipoprotein (LDL), total cholesterol (TC)/high-density lipoprotein (HDL) and anxiety, and increases in V̇O2peak and HDL from baseline to follow-up. Significant main effects of sex revealed smaller V̇O2peak, BMI and waist circumference, and higher LDL, TC and HDL in females than males. HIIT led to similar improvements in estimated V̇O2peak (females: 8.8%, males: 9.0%) and additional health outcomes between sexes. Novelty: HIIT-based cardiac rehabilitation led to similar improvements in estimated V̇O2peak and other physical and mental health outcomes between sexes. The number of sessions attended was high (>70%) and did not differ by sex. Both sexes showed good compliance with the exercise protocol (HR target).

Lessons learned from community- and home-based physical activity programs: A narrative review of factors influencing women's participation in cardiac rehabilitation.

BACKGROUND: Cardiovascular disease remains a leading cause of death in women. Despite the well-known benefits of cardiac rehabilitation, it remains underutilized, especially among women. Physical activity programs in the community, however, attract a large female population, suggesting that they overcome barriers to physical activity encountered by women. The characteristics of interventions that extend beyond the traditional cardiac rehabilitation model and promote physical activity merit examination. OBJECTIVES: This narrative review aimed to: (a) summarize women's barriers to attend cardiac rehabilitation; (b) examine the characteristics of community- and home-based physical activity or lifestyle coaching interventions; and (c) discuss which barriers may be addressed by these alternative programs. METHODS: Studies were included if they: (a) were published within the past 10 years; (b) included ≥70% women with a mean age ≥45 years; (c) implemented a community- or home-based physical activity intervention or a lifestyle education/behavioral coaching program; and (d) aimed to improve physical activity levels or physical function. RESULTS: Most interventions reported high (≥70%) participation rates and significant increases in physical activity levels at follow-up; some improved physical function and/or cardiovascular disease risk factors. Community- and home-based interventions address women's cardiac rehabilitation barriers by: implementing appealing modes of physical activity (e.g. dancing, group-walking, technology-based balance exercises); adapting the program to meet participants' needs; offering flexible options regarding timing and setting (e.g. closer to home, the workplace or faith-based institutions); and promoting social interactions. CONCLUSION: Cardiac rehabilitation can be enhanced by understanding the specific needs of women; novel elements such as program offerings, convenient settings and opportunities for socialization should be considered when designing cardiac rehabilitation programs.

Moving Together While Staying Apart: Practical Recommendations for 24-Hour Home-Based Movement Behaviours for Those With Cardiovascular Disease.

The novel coronavirus disease 2019 is a global public health crisis that disproportionately affects those with preexisting conditions. Cardiovascular disease (CVD) is the leading cause of death worldwide and many key CVD risk factors are modifiable (e.g., physical inactivity, sedentary behaviour, obesity). To limit the spread of coronavirus 2019, most governments have implemented restrictions and recommended staying at home, reducing social contact to a select and exclusive few, and limiting large gatherings. Such public health constraints may have unintended, negative health consequences on 24-hour movement behaviours. The primary purpose of this review is to provide practical at-home recommendations for sedentary time, sleep, and physical activity in those living with CVD. Adults with CVD will benefit from practical recommendations to reduce sedentary time, increase purposeful exercise, and maintain optimal sleep patterns while being at home and adhering to public health restrictions. Our recommendations include the following: (i) self-monitoring sitting time; (ii) engaging in 2-3 days per week of purposeful exercise for those with low exercise capacity and > 3 days per week for those with moderate-to-high exercise capacity; (iii) self-monitoring exercise intensity through the use of scales or wearable devices; (iv) maintaining a regular sleep schedule; and (v) moving daily. Clinicians should be aware that clear communication of the importance of limiting prolonged sedentary time, engaging in regular physical activity and exercise, and ensuring optimal sleep in association with the provision of clear, comprehensible, and practical advice is fundamental to ensuring that those living with CVD respond optimally to the challenges posed by the pandemic.

La nouvelle maladie à coronavirus 2019 représente une crise de santé publique mondiale qui touche de manière disproportionnée les personnes présentant des pathologies préexistantes. Les maladies cardiovasculaires (MCV) constituent la principale cause de décès dans le monde et de nombreux facteurs de risque majeurs de MCV sont modifiables (par exemple, le manque d'activité physique, un comportement sédentaire, l'obésité). Pour limiter la propagation du coronavirus 2019, la plupart des gouvernements ont mis en place des restrictions et recommandé de rester à la maison, de réduire les contacts sociaux à un nombre de personnes restreint et exclusif, et de limiter les grands rassemblements. Ces contraintes de santé publique peuvent involontairement entraîner des conséquences sanitaires négatives sur les habitudes de déplacement sur 24 heures. L'objectif principal de cette étude est de fournir des recommandations pratiques, réalisables à domicile, en rapport avec le temps de sédentarité, le sommeil et l'activité physique chez les personnes atteintes de MCV. Les adultes atteints de MCV tireront avantage de recommandations pratiques dans le but de réduire le temps de sédentarité, augmenter l'activité physique volontaire et maintenir des habitudes de sommeil optimales, tout en restant à la maison et en respectant les restrictions sanitaires. Nos recommandations sont les suivantes: (i) autosurveillance du temps passé assis; (ii) pratique d'une activité physique volontaire 2 à 3 jours par semaine pour les personnes ayant une faible capacité d'exercice et > 3 jours par semaine pour les personnes ayant une capacité d'exercice modérée à élevée; (iii) autosurveillance de l'intensité de l'activité par l'utilisation de barème ou de dispositifs portatifs; (iv) maintien d'horaires de sommeil réguliers; et (v) action de bouger quotidiennement. Les cliniciens doivent être conscients qu'une communication claire quant à l'importance de limiter le temps de sédentarité prolongée, de pratiquer régulièrement de l'exercice ou une activité physique, et d'assurer un sommeil optimal, associée à la préconisation de conseils clairs, compréhensibles et pratiques, est fondamentale pour garantir une réponse optimale de la part des personnes vivant avec des MCV quant aux défis posés par la pandémie.

Sex Differences in Cardiometabolic Health Indicators after HIIT in Patients with Coronary Artery Disease.

PURPOSE: Cardiorespiratory fitness (CRF) is an independent predictor of mortality, and females typically achieve smaller improvements in CRF than males after exercise-based cardiac rehabilitation. High-intensity interval training (HIIT) has been shown to produce superior improvements in CRF than traditional cardiac rehabilitation, but the sex differences are unknown. The purpose of this systematic review and meta-analysis was to evaluate sex differences for changes in CRF and cardiometabolic health indicators after HIIT in adults with coronary artery disease (CAD). METHODS AND RESULTS: A systemic search of five electronic databases for studies examining the effect of HIIT on measured CRF and cardiometabolic health indicators in adults with CAD was performed. Data (published and unpublished) from 14 studies were included in the meta-analyses with approximately eightfold greater male than female participation (n = 836 vs n = 103). Males with CAD achieved a near-significant absolute improvement in CRF (mean difference [MD] = 1.07, 95% confidence interval [CI] = -0.08 to 2.23 mL·kg-1⋅min-1, P = 0.07) after HIIT when compared with control; there were insufficient data to conduct such an analysis in females. Significantly smaller improvements in CRF were experienced by females than males (MD = -1.10, 95% CI = -2.08 to -0.12 mL·kg-1⋅min-1, P = 0.03); there was no sex difference for the relative (percentage) change in CRF after HIIT. Females achieved significantly smaller reductions in body mass index (MD = -0.25, 95% CI = -0.03 to -0.47 kg·m-2, P = 0.02) and fasting blood glucose (MD = -0.38, 95% CI = -0.05 to -0.72, P = 0.03); no sex differences were observed for other cardiometabolic health indicators. CONCLUSION: There are no sex differences for relative improvements in CRF after HIIT; however, females are greatly underrepresented in trials. Future studies should increase female participation and perform sex-based analyses to determine sex-specific outcomes following HIIT.