Acute exercise improves postprandial cardiovascular risk factors in overweight and obese individuals

High Levels of Glycated Hemoglobin (HbA1c) Are Associated with Physical Inactivity, and Part of This Association Is Mediated by Being Overweight

The COVID-19 pandemic has generated substantial changes in the lives of the population, such as increased physical inactivity, which can lead to being overweight and, consequently, repercussions on glucose homeostasis. A cross-sectional study based on the adult population of Brazil was conducted by stratified, multistage probability cluster sampling (October and December 2020). Participants were classified as physically active or inactive during leisure time according to the recommendations of the World Health Organization. HbA1c levels were categorized as normal (≤6.4%) or with glycemic changes (≥6.5%). The mediating variable was being overweight (overweight and obese). Descriptive, univariate, and multivariate logistic regression analyses examined the association between physical inactivity and glycemic changes. Mediation was analyzed using the Karlson-Holm-Breen method to verify the influence of being overweight on the association. We interviewed 1685 individuals, mostly women (52.4%), 35-59 years old (45.8%), race/ethnicity brown (48.1%), and overweight (56.5%). The mean HbA1c was 5.68% (95% CI: 5.58-5.77). Mediation analysis verified that physically inactive participants during leisure time were 2.62 times more likely to have high levels of HbA1c (OR: 2.62, 95% CI: 1.29-5.33), and 26.87% of this effect was mediated by over-weight (OR: 1.30: 95% CI: 1.06-1.57). Physical inactivity at leisure increases the chances of high levels of HbA1c, and part of this association can be explained by being overweight.

Comparative effectiveness of playing golf to Nordic walking and walking on acute physiological effects on cardiometabolic markers in healthy older adults: a randomised cross-over study

Objectives

The acute effects of aerobic exercise on cardiometabolic markers are well documented in younger healthy individuals, but the same effects in older adults have not been elucidated. As such, this study compares the acute effects of three different types of age-appropriate aerobic exercises on cardiometabolic markers.

Methods

Healthy older golfers (n=25, 16 male and 9 female, 68±4 years) were enrolled in a randomised cross-over experiment. We compared the effects of three different acute aerobic exercises (18-hole golf, 6 km Nordic walk, 6 km walk) on blood pressure, blood glucose and blood lipid profile in a real-life environment.

Results

In the between-group comparison, playing golf resulted in a difference in blood glucose (golf: 0.01±1.0 mmol/L, walk: 1.3±0.9 mmol/L, p<0.001) compared with walking and triglycerides (golf: 0.13±0.2 mmol/L, Nordic walk: 0.31±0.2 mmol/L, walk: 0.23±0.2 mmol, p=0.012) and high-density lipoprotein cholesterol (golf: 0.04±0.06 mmol/L, Nordic walk: -0.02±0.06 mmol/L, walk: -0.02±0.07 mmol/L, p=0.002) compared with Nordic walking and walking. In addition, all groups had significant decreases (p<0.001) in systolic blood pressure, and Nordic walking and walking also demonstrated a decrease in diastolic blood pressure (p<0.05).

Conclusion

Acute bouts of aerobic exercise improved cardiovascular profile in healthy older adults. Despite the lower exercise intensity of golf, the longer duration and higher energy expenditure appeared to have a more positive effect on lipid profile and glucose metabolism compared with Nordic walking and walking.

Trial registration number

ISRCTN10007294.

Metabolic responses to acute sprint interval exercise training performed after an oral 75-gram glucose load in individuals with overweight/obesity

There is evidence supporting that acute sprint interval training (SIT) might improve metabolic responses to postprandial glucose, but results are inconclusive. The aim of the present study was to explore the effects of acute SIT on metabolic response and substrate utilization in individuals with overweight/obesity after an oral 75-gram glucose challenge. Thirty-three participants with overweight/ obesity (32.7 ± 8.3 years, 24 male, 9 female) participated in the study and a crossover design was followed. After the 75-gram glucose load, participants were randomly allocated to two groups: no exercise (resting) or SIT protocol. Metabolic data including respiratory quotient (RQ) and substrate utilization rates (fats and carbohydrates) were collected using the COSMED Q-NRG + ® calorimeter. The RQ was significantly lower in the acute SIT group (0.76 [0.01]; p < 0.0001) than in the resting group (0.80 [0.01]; p = 0.036) at the 120-min postprandial time point, and the RQ area under the curve (AUC) was also lower in the SIT group (mean difference of -6.62, 95% CI -12.00 to -1.24; p = 0.0161). The contribution of fat to energy expenditure increased after SIT during the postprandial period whereas the contribution of carbohydrates decreased. The AUC for fat contribution was significantly higher (mean difference 2311.9, 95% confidence interval [CI] 578.8 to 4043.3; p = 0.0098) and the AUC for carbohydrate contribution was significantly lower (mean difference -2283.1, 95% CI -4040.2 to -527.1; p = 0.0117) in the SIT group than in the resting group. In conclusions, acute SIT might have a positive effect on metabolic responses to postprandial glucose and, accordingly, should be recommended for improving metabolism in people with overweight/obesity.

Effectiveness of statins vs. exercise on reducing postprandial hypertriglyceridemia in dyslipidemic population: A systematic review and network meta-analysis

BACKGROUND

Individuals at risk of suffering cardiovascular disease (CVD) present with larger increases in blood triglyceride (TG) concentration after a high-fat meal than do healthy individuals. These postprandial hypertriglyceride levels are an independent risk factor for CVD. Prescription of statins and a bout of prolonged exercise are both effective in lowering postprandial hypertriglyceride levels. We aimed to evaluate the comparative effectiveness of statins vs. a bout of aerobic exercise in reducing fasting and postprandial TG (PPTG) concentrations in individuals at high risk of developing CVD.

METHODS

Thirty-seven studies from a systematic literature search of the PubMed, EMBASE, and Cochrane databases were included in this review. The selected studies conducted trials involving statin therapy (n = 20) or a bout of aerobic exercise (n = 19) and measured their impact on PPTG levels as the outcome. Two studies analyzed both treatments and were included in duplicate. The meta-analysis was constructed using a random-effects model to calculate the mean difference (MD). The Student t test was used to compare the data sets for statins vs. exercise.

RESULTS

Overall, statin and exercise interventions showed similar reductions in PPTG levels, with an MD of -0.65 mmol/L for statins (95% confidence interval (95%CI): -0.54 to -0.77; p < 0.001) and -0.46 mmol/L for exercise (95%CI: -0.21 to -0.71; p < 0.01). However, statins lowered fasting TG levels more than exercise (MD = -1.54 mmol/L, 95%CI: -2.25 to -0.83; p = 0.009).

CONCLUSION

Although aerobic exercise is effective in lowering blood TG levels, statins seem to be more efficient, especially in the fasted state. A combination of exercise and statins might reveal a valuable approach to the treatment and prevention of CVD. More studies are required to determine the underlying mechanisms and the possible additive effects of these interventions.

Effect of Prior Exercise on Postprandial Lipemia: An Updated Meta-Analysis and Systematic Review

The purpose of this systematic review was to synthesize the results from current literature examining the effects of prior exercise on the postprandial triglyceride (TG) response to evaluate current literature and provide future direction. A quantitative review was performed using meta-analytic methods to quantify individual effect sizes. A moderator analysis was performed to investigate potential variables that could influence the effect of prior exercise on postprandial TG response. Two hundred and seventy-nine effects were retrieved from 165 studies for the total TG response and 142 effects from 87 studies for the incremental area under the curve TG response. There was a moderate effect of exercise on the total TG response (Cohen's d = -0.47; p < .0001). Moderator analysis revealed exercise energy expenditure significantly moderated the effect of prior exercise on the total TG response (p < .0001). Exercise modality (e.g., cardiovascular, resistance, combination of both cardiovascular and resistance, or standing), cardiovascular exercise type (e.g., continuous, interval, concurrent, or combined), and timing of exercise prior to meal administration significantly affected the total TG response (p < .001). Additionally, exercise had a moderate effect on the incremental area under the curve TG response (Cohen's d = -0.40; p < .0001). The current analysis reveals a more homogeneous data set than previously reported. The attenuation of postprandial TG appears largely dependent on exercise energy expenditure (∼2 MJ) and the timing of exercise. The effect of prior exercise on the postprandial TG response appears to be transient; therefore, exercise should be frequent to elicit an adaptation.

An updated systematic review on the effects of aerobic exercise on human blood lipid profile

Sedentary lifestyle and dyslipidemia are well-recognized risk factors for cardiovascular diseases (CVD). Changes in blood lipid profile (total cholesterol (TC), triglycerides, high-density lipoprotein [HDL], and low-density lipoprotein [LDL]) due to the exercise may be beneficial for decreasing CVD-related events. In this review we aimed to investigate the effect of different types of exercise on lipid profile components in people with different health conditions and age ranges. A systematic search was performed covering PubMed, Web of Science, and Google Scholar for English articles from 2010 until November 2021. Finally, 31 studies were included in our study. Results showed that exercise in younger individuals sometimes resulted in no significant changes of any of the variables or some of them; however, efficient improvement was observed in all studies of older and middle-age groups. In terms of health condition and gender; healthy individuals, overweight people, subjects with type 2 diabetes and obesity, and male participants found to have benefited more from the exercise. In patients with chronic kidney diseases lipid profile improvement was not significant. The cardiac rehabilitation program, particularly comprehensive cardiac rehabilitation, proved to be more beneficial than exercise alone in the case of cardiovascular patients and those at elevated risk of CVD. In conclusion exercise is beneficial in terms of improving lipid profile but for younger population, and those with kidney problems and CVD patients, more further preparations are needed under the supervision of experts in the field of sports and medicine to achieve the desired result. Also, more studies are needed for these groups in order to provide a definite and reliable conclusion.

A META-ANALYSIS OF THE EFFECTS OF GREEN TEA COMBINED WITH PHYSICAL ACTIVITY ON BLOOD LIPIDS IN HUMANS

ABSTRACT Introduction: Most studies of green tea extract (GTE) combined with physical activity have reported a preventative effect for cardiovascular disease; however, the findings regarding the effects on serum lipids are controversial. Objective: This meta-analysis aimed to examine the evidence of the effects of GTE combined with physical activity on the serum lipid content in humans. Methods: In June 2017, we conducted electronic searches of PubMed, Web of Science, and Cochrane Library to identify pertinent studies: those with an experiment period exceeding two weeks, human randomized controlled trials (RCTs), and those that only assessed GTE with physical activity were included. A random effects model meta-analysis was used in this review. Results: A total of 271 citations were retrieved in our search of the electronic literature, and 7 RCTs, which included 608 individuals, were identified. Overall, there was no significant decrease in low-density lipoprotein cholesterol (LDL-C) (SMD:-0.169; 95% confidence interval [CI]:-0.414 to 0.076; I2=22.7%; p=0.177) or total cholesterol (TC) levels between the GTE and placebo combined with the physical activity group. Similar results were also observed for high density-lipoprotein cholesterol (HDL-C) and triglycerides (TG). In the subgroup and sensitivity analyses of the five studies, the TC levels of the subjects who received a lower dose of epigallocatechin gallate (EGCG) together with performing physical activity were significantly decreased. Conclusion: Current evidence suggests that green tea combined with physical activity does not improve the lipid and lipoprotein levels in humans. Level of evidence I; Systematic review.

Acute exercise effects on postprandial fat oxidation: meta-analysis and systematic review

The purpose of this systematic review was to synthesize and evaluate current literature examining the effects of exercise on postprandial fat oxidation, as well as to provide future direction. A quantitative review was performed using meta-analytic methods. A moderator analysis was performed to investigate potential variables that could influence the effect of exercise on postprandial fat oxidation. Fifty-six effects from 26 studies were retrieved. There was a moderate effect of exercise on postprandial fat oxidation (Cohen's d = 0.58 (95% CI, 0.39 to 0.78)). Moderator analysis revealed that sex, age, weight status, training status, exercise type, exercise intensity, timing of exercise, and composition of the meal challenge significantly affected the impact of prior exercise on postprandial fat oxidation. The moderator analysis also indicated that most previous studies have investigated the impact of prior moderate-intensity endurance exercise on postprandial fat oxidation in young, healthy, lean men. Suggested priorities for future research in this area include (i) an examination of sex differences in and/or female-specific aspects of postprandial metabolism; (ii) a comprehensive evaluation of exercise modalities, intensities, and durations; and (iii) a wider variety of test meal compositions, especially those with higher fat content. Novelty A systematic review of the impact of exercise on postprandial fat oxidation was performed using meta-analytic methods. Analysis revealed a moderate effect of exercise on postprandial fat oxidation. The presented data support a need for future studies to investigate sex differences and to include comprehensive evaluations of exercise modalities, intensities, and duration.

Twenty Minute Moderate-Intensity Post-Dinner Exercise Reduces the Postprandial Glucose Response in Chinese Patients with Type 2 Diabetes

BACKGROUND Postprandial hyperglycemia and glycemic fluctuations are significant cardiovascular disease risk factors for patients with type 2 diabetes. We investigated the effects of a single session of post-dinner moderate-intensity exercise on the postprandial glycemic response compared with a non-exercise condition in a study population of Chinese patients with type 2 diabetes. MATERIAL AND METHODS This randomized crossover self-controlled pilot study involved 29 patients with type 2 diabetes who participated in post-dinner exercise days using non-exercise days as a control. The interstitial glucose level was monitored using a continuous glucose monitoring system, with a standardized diet and medication. For the non-exercise control days, patients pursued normal daily activities but refrained from unusual strenuous physical activity. On the exercise days, participants walked on a treadmill for 20 minutes after dinner, with a heart rate reserve of 40%. RESULTS Post-dinner moderate-intensity exercise reduced the 2-hour postprandial glucose spike, mean glucose level, and peak glucose level compared to the control condition. The cumulative glucose total area under the curve during 1-hour post-exercise was lower with exercise than under the control condition. The 12-hour standard deviation of blood glucose and the coefficient variation of glucose were significantly lower in the with exercise day compared to the control day, although the 12-hour mean amplitude of glycemic fluctuations did not reach statistical significance. No nocturnal hypoglycemia subsequently occurred on the exercise day. CONCLUSIONS A short session of moderate-intensity post-dinner exercise can improve postprandial hyperglycemia and glycemic excursions in Chinese patients with type 2 diabetes, with no potential hypoglycemia risk at a later period.

[Effect of moderate exercise for 30 min at 30 min versus 60 min after dinner on glycemic control in patients with type 2 diabetes: a randomized, crossover, self-controlled study]

OBJECTIVE

To compare the effectiveness of moderate exercise for 30 min at 30 min and 60 min after dinner on glycemic control in patients with type 2 diabetes.

METHODS

This randomized, crossover, self-controlled pilot study was conducted in 15 inactive patients with type 2 diabetes without serious complications or use of exogenous insulin. The participants completed two randomly ordered exercise protocols (brisk walking for 30 min at 30 min or 60 min after dinner on the exercise day) spaced 1 week apart. All the exercise was performed while maintaining a heart rate reserve of 40%. The interstitial glucose level was monitored using a continuous glucose monitor (CGM) for all the participants, who maintained a standardized diet with routine medications. The 2-h postprandial mean glucose, peak glucose, and glucose area under the curve (AUC) were measured. The mean amplitude of glycemic excursions (MAGE) and other plasma glucose fluctuation parameters in 12 h after dinner, including the mean blood glucose (MBG) and the coefficient variation (CV) of glucose, were also calculated. The incidence of nocturnal hypoglycemia was recorded in all the participants.

RESULTS

The participants had a mean age of 46±11 years with a mean BMI of 25.8±3.1 kg/m2 and a mean HbA1c of 7.7%. No significant differences were found between postprandial 30 min exercise group and postprandial 60 min exercise group in terms of 2-h postprandial mean glucose, peak glucose, glucose AUC, or in MBG, CV and MAGE during the 12-h period after dinner. No nocturnal hypoglycemia occurred in the participants after exercise at 30 or 60 min after dinner. However, significant reductions in the 2-h postprandial glucose levels were detected after exercise at 60 min after dinner as compared to exercise at 30 min.

CONCLUSIONS

The timing (30 min vs 60 min after dinner) of moderate exercises for 30 min does not produce significant difference in the improvement of postprandial hyperglycemia in type 2 diabetic patients, and both exercise protocols are safe without a potential risk of hypoglycemia. Nevertheless, exercise at 60 min after dinner can be more effective to lower 2-h postprandial glucose, while exercise at 30 min after dinner might be safer for patients with a high risk of hypoglycemia.

Using new technologies to promote weight management: a randomised controlled trial study protocol

Background

Over the last three decades, overweight and obesity and the associated health consequences have become global public health priorities. Methods that have been tried to address this problem have not had the desired impact, suggesting that other approaches need to be considered. One of the lessons learned throughout these attempts is that permanent weight loss requires sustained dietary and lifestyle changes, yet adherence to weight management programs has often been noted as one of the biggest challenges. This trial aims to address this issue by examining whether social media, as a potential health promotion tool, will improve adherence to a weight management program. To test the effectiveness of this measure, the designated program will be delivered via the popular social networking site Facebook, and compared to a standard delivery method that provides exactly the same content but which is communicated through a pamphlet. The trial will be conducted over a period of twelve weeks, with a twelve week follow-up. Although weight loss is expected, this study will specifically investigate the effectiveness of social media as a program delivery method. The program utilised will be one that has already been proven to achieve weight loss, namely The CSIRO Total Wellbeing Diet.

Methods/design

This project will be conducted as a 3-arm randomised controlled trial. One hundred and twenty participants will be recruited from the Perth community, and will be randomly assigned to one of the following three groups: the Facebook group, the pamphlet group, or a control group. The Facebook Group will receive the weight management program delivered via a closed group in Facebook, the Pamphlet Group will be given the same weight management program presented in a booklet, and the Control Group will follow the Australian Dietary Guidelines and the National Physical Activity Guidelines for Adults as usual care. Change in weight, body composition and waist circumference will be initial indicators of adherence to the program. Secondary outcome measures will be blood glucose, insulin, blood pressure, arterial stiffness, physical activity, eating behaviour, mental well-being (stress, anxiety, and depression), social support, self-control, self-efficacy, Facebook activity, and program evaluation.

Discussion

It is expected that this trial will support the use of social media - a source of social support and information sharing - as a delivery method for weight management programs, enhancing the reduction in weight expected from dietary and physical activity changes. Facebook is a popular, easy to access and cost-effective online platform that can be used to assist the formation of social groups, and could be translated into health promotion practice relatively easily. It is anticipated in the context of the predicted findings that social media will provide an invaluable resource for health professionals and patients alike.

Trial registration

Australian New Zealand Clinical Trials Register (ANZCTR): ACTRN12614000536662. Date registered: 21 May 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1849-4) contains supplementary material, which is available to authorized users.

Weight-loss intervention using implementation intentions and mental imagery: a randomised control trial study protocol

BACKGROUND

Overweight and obesity are major health problems worldwide. This protocol describes the HEALTHI (Healthy Eating and Active LifesTyle Health Intervention) Program, a 12-week randomised-controlled weight-loss intervention that adopts two theory-based intervention techniques, mental imagery and implementation intentions, a behaviour-change technique based on planning that have been shown to be effective in promoting health-behaviour change in previous research. The effectiveness of goal-reminder text messages to augment intervention effects will also be tested. The trial will determine the effects of a brief, low cost, theory-based weight-loss intervention to improve dietary intake and physical activity behaviour and facilitate weight-loss in overweight and obese individuals.

METHODS/DESIGN

Overweight or obese participants will be randomly allocated to one of three conditions: (1) a psycho-education plus an implementation intentions and mental imagery condition; (2) a psycho-education plus an implementation intentions and mental imagery condition with text messages; or (3) a psycho-education control condition. The intervention will be delivered via video presentation to increase the intervention's applicability in multiple contexts and keep costs low. We hypothesise that the intervention conditions will lead to statistically-significant changes in the primary and secondary outcome variables measured at 6 and 12 weeks post-intervention relative to the psycho-education control condition after controlling for baseline values. The primary outcome variable will be body weight and secondary outcome variables will be biomedical (body mass, body fat percentage, muscle mass, waist-hip circumference ratio, systolic and diastolic blood pressure, low-density lipoprotein, high-density lipoprotein, total cholesterol, triglycerides, blood glucose and insulin levels), psychological (quality of life, motivation, risk perception, outcome expectancy, intention, action self-efficacy, maintenance self-efficacy, goal setting and planning), and behavioural (self-reported diet intake, and physical activity involvement) measures. We also expect the intervention condition augmented with text messages to lead to statistically significant differences in the primary and secondary outcome variables at the follow up periods after controlling for baseline values.

DISCUSSION

The planned trial will test the effectiveness of the theory-based HEALTHI program intervention to reduce weight and salient psychological, biomedical, and behavioural outcomes in overweight and obese adults. The study has been designed to maximise applicability to real world settings and could be integrated into existing weight management practices.

TRIAL REGISTRATION

ACTRN: ACTRN12613001274763. Registration date 19/11/2013.

Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not

OBJECTIVES

To explore the effects of breaking up prolonged sitting time with standing or light-intensity walking on a range of cardiometabolic risk markers.

DESIGN

A randomised three-period, three-treatment acute crossover trial.

METHODS

Ten non-obese adults took part in three trials: (1) uninterrupted sitting; (2) seated with 2-min bouts of standing every 20 min; and (3) seated with 2-min bouts of light-intensity walking every 20 min. Two standardised test drinks (total 80.3 carbohydrate, 50 g fat) were provided after an initial 1-h period of uninterrupted sitting. Plasma glucose and blood pressure were assessed hourly to calculate area under the curve. Total cholesterol, HDL, and triglycerides were assessed at baseline and 5-h. ANOVAs were used to explore between-trial differences.

RESULTS

Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions: mean area under the curve 18.5 (95% CI 17, 20), 22.0 (20.5, 23.5), and 22.2 (20.7, 23.7) mmol L/5-h, respectively, p<0.001; no difference between uninterrupted sitting and standing-break conditions (p>0.05). Systolic and diastolic blood pressure area under the curve did not differ significantly between conditions, nor did responses in lipid parameters (p>0.05).

CONCLUSIONS

This study suggests that interrupting sitting time with frequent brief bouts of light-intensity activity, but not standing, imparts beneficial postprandial responses that may enhance cardiometabolic health. These findings may have importance in the design of effective interventions to reduce cardiometabolic disease risk.

Potential benefits of exercise on blood pressure and vascular function

Physical activity seems to enhance cardiovascular fitness during the course of the lifecycle, improve blood pressure, and is associated with decreased prevalence of hypertension and coronary heart disease. It may also delay or prevent age-related increases in arterial stiffness. It is unclear if specific exercise types (aerobic, resistance, or combination) have a better effect on blood pressure and vascular function. This review was written based on previous original articles, systematic reviews, and meta-analyses indexed on PubMed from years 1975 to 2012 to identify studies on different types of exercise and the associations or effects on blood pressure and vascular function. In summary, aerobic exercise (30 to 40 minutes of training at 60% to 85% of predicted maximal heart rate, most days of the week) appears to significantly improve blood pressure and reduce augmentation index. Resistance training (three to four sets of eight to 12 repetitions at 10 repetition maximum, 3 days a week) appears to significantly improve blood pressure, whereas combination exercise training (15 minutes of aerobic and 15 minutes of resistance, 5 days a week) is beneficial to vascular function, but at a lower scale. Aerobic exercise seems to better benefit blood pressure and vascular function.

The effects of sex, metabolic syndrome and exercise on postprandial lipemia

OBJECTIVE

Exercise has been suggested to have cardioprotective benefits due to a lowering of postprandial triglycerides (PPTG). We hypothesized that a morning exercise bout would significantly lower PPTG measured over a full day, in response to moderate fat meals (35% energy) in men more so than women, and in metabolic syndrome (MetS) relative to normal weight (NW) individuals.

MATERIALS/METHODS

Participants completed two randomized study days; one control and one exercise day (60 min of morning exercise, 60% VO(2peak)). Meals were consumed at breakfast, lunch and dinner with the energy expended during exercise replaced on the active day. The areas (AUC) and incremental areas (IAUC) under the curve were calculated for total triglycerides, total cholesterol and other metabolites.

RESULTS

Exercise did not significantly change the PPTG AUC & IAUC overall, or within, or between, each sex or group (NW and MetS). Exercise induced a 30% decrease in total cholesterol IAUC (p=0.003) in NW subjects. Overall, women had a lower IAUC for PPTG compared to men (p=0.037), with the greatest difference between MetS women and MetS men, due to a sustained drop in TG after lunch in the women. This suggests that PP, rather than fasting, lipid analyses may be particularly important when evaluating sex differences in metabolic risk.

CONCLUSIONS

With energy replacement, moderate morning exercise did not result in a significant decrease in PPTG excursions. Exercise did elicit a significant decrease in PP cholesterol levels in NW subjects, suggesting a potential mechanism for the cardioprotective effects of exercise.

The effect of 12 weeks of aerobic, resistance or combination exercise training on cardiovascular risk factors in the overweight and obese in a randomized trial

BACKGROUND

Evidence suggests that exercise training improves CVD risk factors. However, it is unclear whether health benefits are limited to aerobic training or if other exercise modalities such as resistance training or a combination are as effective or more effective in the overweight and obese. The aim of this study is to investigate whether 12 weeks of moderate-intensity aerobic, resistance, or combined exercise training would induce and sustain improvements in cardiovascular risk profile, weight and fat loss in overweight and obese adults compared to no exercise.

METHODS

Twelve-week randomized parallel design examining the effects of different exercise regimes on fasting measures of lipids, glucose and insulin and changes in body weight, fat mass and dietary intake. Participants were randomized to either: Group 1 (Control, n = 16); Group 2 (Aerobic, n = 15); Group 3 (Resistance, n = 16); Group 4 (Combination, n = 17). Data was analysed using General Linear Model to assess the effects of the groups after adjusting for baseline values. Within-group data was analyzed with the paired t-test and between-group effects using post hoc comparisons.

RESULTS

Significant improvements in body weight (-1.6%, p = 0.044) for the Combination group compared to Control and Resistance groups and total body fat compared to Control (-4.4%, p = 0.003) and Resistance (-3%, p = 0.041). Significant improvements in body fat percentage (-2.6%, p = 0.008), abdominal fat percentage (-2.8%, p = 0.034) and cardio-respiratory fitness (13.3%, p = 0.006) were seen in the Combination group compared to Control. Levels of ApoB48 were 32% lower in the Resistance group compared to Control (p = 0.04).

CONCLUSION

A 12-week training program comprising of resistance or combination exercise, at moderate-intensity for 30 min, five days/week resulted in improvements in the cardiovascular risk profile in overweight and obese participants compared to no exercise. From our observations, combination exercise gave greater benefits for weight loss, fat loss and cardio-respiratory fitness than aerobic and resistance training modalities. Therefore, combination exercise training should be recommended for overweight and obese adults in National Physical Activity Guidelines.This clinical trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), registration number: ACTRN12609000684224.

Resistance, aerobic, and combination training on vascular function in overweight and obese adults

The authors investigated the effects of moderate-intensity resistance, aerobic, or combined exercise on blood pressure and arterial stiffness in overweight and obese individuals compared with no exercise. Participants were randomized to 4 groups: control, aerobic, resistance, and combination. Assessments were made at baseline, week 8, and week 12. In participant-designated responders, those in the intervention groups who had improved levels of systolic blood pressure (SBP) or augmentation index (AI), we observed a significant decrease of SBP in aerobic (-4%, P=.027), resistance (-5.1%, P=.04), and combination groups (-6.3%, P=.000) at week 8 and in the combination group (-6.3%, P=.005) at week 12, compared with baseline. AI was significantly lower at week 12 in the aerobic (-12%, P=.047), resistance (-9.5%, P=.036), and combination (-12.7%, P=.003) groups compared with baseline, as well as in the combination group (-10.7%, P=.047) compared with the control group. We did not observe significant changes in SBP, DBP, or AI between the interventions when assessing the entire cohort, although there were significant improvements in a subgroup of responders. Thus, some but not all overweight and obese individuals can improve blood pressure and arterial stiffness by participating in regular combination exercise, decreasing the risk of developing cardiovascular disease.

Effects of aerobic exercise training on variability and heart rate kinetic during submaximal exercise after gastric bypass surgery--a randomized controlled trial

BACKGROUND

This study aimed to determine whether morbidly obese women have an alteration of heart rate (HR) kinetics and HR variability (HRV) during the 6-min walk test (6MWT) and if an aerobic exercise training can modify these indexes after gastric bypass surgery (GBS).

DESIGN AND METHODS

Nineteen morbidly obese women were randomized to a trained (TG) or control group and 12 women of eutrophic group (EG) were also evaluated. The obese women were tested on two occasions: 1 week before and 4 months after GBS through record of HR and R-R intervals during 6MWT for analysis HR kinetics. The TG underwent an aerobic exercise training program on a treadmill (1-h session, totaling 36 sessions over 12-week).

RESULTS

Both obese groups demonstrated a significant reduction of rMSSD and slower HR kinetics during the 6MWT when compared to the EG. In addition, only the TG demonstrated a significant improvement in HRV indexes, walking distance, faster time constant and mean response time of HR during 6MWT after training (p < 0.05).

CONCLUSION

Morbidly obese women have slower HR kinetics and altered cardiac modulation during submaximal exercise. However, aerobic exercise training can produce beneficial adaptations in HRV and faster HR kinetics following GBS.

Breaking up prolonged sitting reduces postprandial glucose and insulin responses

OBJECTIVE

Observational studies show breaking up prolonged sitting has beneficial associations with cardiometabolic risk markers, but intervention studies are required to investigate causality. We examined the acute effects on postprandial glucose and insulin levels of uninterrupted sitting compared with sitting interrupted by brief bouts of light- or moderate-intensity walking.

RESEARCH DESIGN AND METHODS

Overweight/obese adults (n = 19), aged 45-65 years, were recruited for a randomized three-period, three-treatment acute crossover trial: 1) uninterrupted sitting; 2) seated with 2-min bouts of light-intensity walking every 20 min; and 3) seated with 2-min bouts of moderate-intensity walking every 20 min. A standardized test drink was provided after an initial 2-h period of uninterrupted sitting. The positive incremental area under curves (iAUC) for glucose and insulin (mean [95% CI]) for the 5 h after the test drink (75 g glucose, 50 g fat) were calculated for the respective treatments.

RESULTS

The glucose iAUC (mmol/L) · h after both activity-break conditions was reduced (light: 5.2 [4.1-6.6]; moderate: 4.9 [3.8-6.1]; both P < 0.01) compared with uninterrupted sitting (6.9 [5.5-8.7]). Insulin iAUC (pmol/L) · h was also reduced with both activity-break conditions (light: 633.6 [552.4-727.1]; moderate: 637.6 [555.5-731.9], P < 0.0001) compared with uninterrupted sitting (828.6 [722.0-950.9]).

CONCLUSIONS

Interrupting sitting time with short bouts of light- or moderate-intensity walking lowers postprandial glucose and insulin levels in overweight/obese adults. This may improve glucose metabolism and potentially be an important public health and clinical intervention strategy for reducing cardiovascular risk.