Two weeks of exercise training intensity on appetite regulation in obese adults with prediabetes

Exercise Training Independent of Intensity Lowers Plasma Bile Acids in Prediabetes

INTRODUCTION

People with obesity have high circulating bile acids (BA). Although aerobic fitness favors low circulating BA, the effect of training intensity before clinically meaningful weight loss on BA is unclear. This study aimed to test the hypothesis that 2 wk of interval (INT) versus continuous (CONT) exercise would lower plasma BA in relation to insulin sensitivity.

METHODS

Twenty-three older adults with prediabetes (ADA criteria) were randomized to 12 work-matched bouts of INT ( n = 11, 60.3 ± 2.4 yr, 32.1 ± 1.2 kg·m -2 ) at 3 min at 50% HR peak and 3 min at 90% HR peak or CONT ( n = 12, 60.8 ± 2.4 yr, 34.0 ± 1.7 kg·m -2 ) at 70% HR peak cycling training for 60 min·d -1 over 2 wk. A 180-min 75-g oral glucose tolerance test (OGTT) was performed to assess glucose tolerance (tAUC), insulin sensitivity (Siis), and metabolic flexibility (RER postprandial -RER fast ; indirect calorimetry). BA ( n = 8 conjugated and 7 unconjugated) were analyzed at 0, 30, and 60 min of the OGTT. Anthropometrics and fitness (V̇O 2peak ) were also assessed.

RESULTS

INT and CONT comparably reduced body mass index (BMI; P < 0.001) and fasting RER ( P < 0.001) but raised insulin sensitivity ( P = 0.03). INT increased V̇O 2peak as compared with CONT ( P = 0.01). Exercise decreased the unconjugated BA chenodeoxycholic acid iAUC 60min ( P < 0.001), deoxycholic acid iAUC 60min ( P < 0.001), lithocholic acid iAUC 60min ( P < 0.001), and glycodeoxycholic acid (GCDCA) iAUC 60min ( P < 0.001). Comparable reductions were also seen in the conjugated BA hyodeoxycholic acid iAUC 60min ( P = 0.01) and taurolithocholic acid iAUC 60min ( P = 0.007). Increased V̇O 2peak was associated with lowered UDCA 0min ( r = -0.56, P = 0.02) and cholic acid iAUC 60min ( r = -0.60, P = 0.005), whereas reduced BMI was related to higher GDCA 0min ( r = 0.60, P = 0.005) and GCDCA 0min ( r = 0.53, P = 0.01). Improved insulin sensitivity correlated with lower GCDCA iAUC 60min ( r = -0.45, P = 0.03) and GDCA iAUC 60min ( r = -0.48, P = 0.02), whereas increased metabolic flexibility was related to deoxycholic acid iAUC 60min ( r = 0.64, P = 0.004) and GCDCA iAUC 60min ( r = 0.43, P = 0.05).

CONCLUSIONS

Short-term training lowers some BA in relation to insulin sensitivity independent of intensity.

The Influence of Acute and Chronic Exercise on Appetite and Appetite Regulation in Patients with Prediabetes or Type 2 Diabetes Mellitus-A Systematic Review

This systematic review aims to analyze the effects of acute and chronic exercise on appetite and appetite regulation in patients with abnormal glycemic control. PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials were searched for eligible studies. The included studies had to report assessments of appetite (primary outcome). Levels of appetite-regulating hormones were analyzed as secondary outcomes (considered, if additionally reported). Seven studies with a total number of 211 patients with prediabetes or type 2 diabetes mellitus (T2DM) met the inclusion criteria. Ratings of hunger, satiety, fullness, prospective food consumption, nausea, and desire to eat, as well as levels of (des-)acylated ghrelin, glucagon-like peptide 1, glucose-dependent insulinotropic peptide, pancreatic polypeptide, peptide tyrosine tyrosine, leptin, and spexin were considered. Following acute exercise, the effects on appetite (measured up to one day post-exercise) varied, while there were either no changes or a decrease in appetite ratings following chronic exercise, both compared to control conditions (without exercise). These results were accompanied by inconsistent changes in appetite-regulating hormone levels. The overall risk of bias was low. The present results provide more evidence for an appetite-reducing rather than an appetite-increasing effect of (chronic) exercise on patients with prediabetes or T2DM. PROSPERO ID: CRD42023459322.

Exercise increases TCA intermediate concentrations during low-calorie diet independent of insulin resistance among women with obesity

Tricarboxylic acid cycle intermediates (TCAi) have been proposed to act as myokines that influence energy metabolism. We determined if 2-weeks of low-calorie diet with interval exercise (LCD + INT) would increase TCAi more than a low-calorie diet (LCD). Twenty-three women were randomized to 2-weeks of LCD (n = 12, 48.4 ± 2.5 years, 37.8 ± 1.5 kg/m2, ~1200 kcal/d) or LCD + INT (n = 11, 47.6 ± 4.3 years, 37.9 ± 2.3 kg/m2; 60 min/d supervised INT of 3 min 90% & 50% HRpeak). TCAi and amino acids (AA) were measured at 0 min of a 75 g OGTT, while glucose, insulin, and FFA were obtained at 0, 30, 60, 90, 120, and 180 min to assess total area under the curve (tAUC180min) and insulin resistance (IR; tAUC180min of Glucose × Insulin). Fuel use (indirect calorimetry) was also collected at 0, 60, 120, and 180 min as was fitness (VO2peak) and body composition (BodPod). Treatments reduced weight (p < 0.001), fasting RER (p = 0.01), and IR (p = 0.03), although LCD + INT increased VO2peak (p = 0.02) and maintained RER tAUC180min (p = 0.05) versus LCD. Treatments increased FFA tAUC180min (p = 0.005), cis-aconitate, isocitrate, and succinate (p ≤ 0.02), as well as reduced phenylalanine and tryptophan, cysteine (p ≤ 0.005). However, LCD + INT increased malate, citrate, α-ketoglutarate, and alanine more than LCD (p ≤ 0.04). Thus, INT enhanced LCD effects on some TCAi in women with obesity independent of IR.

Early chronotype favors appetite and reduced later day caloric intake among adults with obesity

Late chronotype (LC) is related to obesity and altered food intake throughout the day. But whether appetite perception and gut hormones differ among chronotypes is unclear. Thus, we examined if early chronotype (EC) have different appetite responses in relation to food intake than LC. Adults with obesity were categorized using the Morningness-Eveningness Questionnaire (MEQ) as either EC (n = 21, 18F, MEQ = 63.9 ± 1.0, 53.7 ± 1.2 yr, 36.2 ± 1.1 kg/m2) and LC (n = 28, 24F, MEQ = 47.2 ± 1.5, 55.7 ± 1.4 yr, 37.1 ± 1.0 kg/m2). Visual analog scales were used during a 120 min 75 g oral glucose tolerance test (OGTT) at 30 min intervals to assess appetite perception, as well as glucose, insulin, GLP-1 (glucagon-like polypeptide-1), GIP (glucose-dependent insulinotrophic peptide), PYY (protein tyrosine tyrosine), and acylated ghrelin. Dietary intake (food logs), resting metabolic rate (RMR; indirect calorimetry), aerobic fitness (maximal oxygen consumption (VO2max)), and body composition dual-energy X-ray absorptiometry (DXA) were also assessed. Age, body composition, RMR, and fasting appetite were similar between groups. However, EC had higher satisfaction and fullness as well as reduced desires for sweet, salty, savory, and fatty foods during the OGTT (P <0.05). Only GIP tAUC0-120 min was elevated in EC versus LC (p = 0.01). Daily dietary intake was similar between groups, but EC ate fewer carbohydrates (p = 0.05) and more protein (p = 0.01) at lunch. Further, EC had lower caloric (p = 0.03), protein (p = 0.03) and fat (p = 0.04) intake during afternoon snacking compared to LC. Dietary fat was lower, and carbohydrates was higher, in EC than LC (p = 0.05) at dinner. Low glucose and high insulin as well as GLP-1 tAUC60-120 min related to desires for sweet foods (p < 0.05). Taken together, EC had more favorable appetite and lower caloric intake later in the day compared with LC.

A low-calorie diet raises β-aminoisobutyric acid in relation to glucose regulation and leptin independent of exercise in women with obesity

Introduction: β-aminoisobutyric acid (BAIBA) is a suggested cytokine secreted from skeletal muscles that regulates insulin sensitivity, pancreatic function, and fat oxidation. However, no studies to date have examined if a low-calorie diet (LCD) or LCD + with interval exercise (LCD + INT) differentially raises BAIBA. The purpose was to examine if LCD or LCD + INT raises circulating BAIBA in relation to cardiometabolic health. Methods: For this, twenty-three women with obesity were randomized to either 2-weeks of LCD (n = 12, 48.4 ± 2.5 y, 37.84 ± 1.5 kg/m2; ∼1200 kcal/day) or LCD + INT (n = 11, 47.6 ± 4.3 y, 37.9 ± 2.3 kg/m2; ∼60 min/d of INT alternating 3 min of 90% and 50% HRpeak), with matched energy availability. Fasting BAIBA and adipokines along with glucose, insulin, C-peptide, and FFA after every 30 min up to 120 min were obtained during a 75 g OGTT to estimate total area under the curve (tAUC), insulin sensitivity (SIIS), pancreatic function [disposition index (DI)], and hepatic insulin clearance (HIC). Fuel use (indirect calorimetry) was tested at 0, 60, and 120 min of the OGTT along with fitness (VO2peak) and body composition (BodPod). Results: Both treatments lowered body weight (p < 0.001) and leptin (p < 0.001) but raised BAIBA (p = 0.007) and insulin sensitivity (p = 0.02). LCD + INT increased VO2peak (p = 0.02) and REE tAUC120min (p = 0.02) while LCD and LCD + INT decreased carbohydrate oxidation (CHOox) tAUC120min (p < 0.001). Increased BAIBA associated with reduced weight (r = -0.67, p < 0.001), leptin (r = -0.66, p = 0.001), CHOox tAUC120min (r = -0.44, p = 0.03) and DImuscle120min (r = -0.45, p = 0.03), but elevated HIC120min (r = 0.47, p = 0.02). Discussion: Concluding, LCD and LCD + INT increased BAIBA in relation to reduced body weight and pancreatic function in women with obesity. This suggests energy deficit is a key factor regulating circulating BAIBA.

Plasma LEAP-2 Following a Low-Calorie Diet with or without Interval Exercise in Women with Obesity

Liver-expressed antimicrobial peptide-2 (LEAP-2) is associated with caloric intake and glucose metabolism. Purpose: Assess if a low-calorie diet with interval exercise (LCD+INT) raises LEAP-2 more than LCD in relation to appetite and cardiometabolic health. Methods: Women with obesity were randomized to either 2 weeks of LCD (n = 13, ~1200 kcal/d) or LCD+INT (n = 12; 60 min/d) of INT at 3 min of 90% and 50% HRpeak, respectively. LEAP-2 and acylated ghrelin (AG) were measured at 0, 30, and 60 min, while glucose, insulin, C-peptide, and free fatty acids (FFA) were obtained up to 180 min of a 75 g OGTT. Fasting and 120 min OGTT appetite were assessed via visual analog scales. Results: LCD reduced the BMI (p < 0.001) compared with LCD+INT, but only LCD+INT increased the VO2 max (p = 0.04). Treatments reduced fasting LEAP-2 (p = 0.05), but only LCD increased LEAP-2 iAUC60 min (p = 0.06) and post-prandial LEAP-2 stimulation (p = 0.02). Higher post-LEAP-260 min tended to relate to a lower desire to eat 120 min of sweet (r = 0.40, p = 0.07) and salty foods (r = 0.41, p = 0.06), as well as lower AG30 min (r = -0.51, p = 0.01) and higher FFA iAUC180 min (r = 0.56, p = 0.007) post-treatment. Conclusion: LCD, with or without INT, reduced fasting LEAP-2, but only LCD raised post-prandial LEAP-2. How diet and exercise impact LEAP-2 for lower chronic disease risk awaits further investigation.

Relation of Aortic Waveforms with Gut Hormones following Continuous and Interval Exercise among Older Adults with Prediabetes

Prediabetes raises cardiovascular disease risk, in part through elevated aortic waveforms. While insulin is a vasodilatory hormone, the gut hormone relation to aortic waveforms is less clear. We hypothesized that exercise, independent of intensity, would favor aortic waveforms in relation to gut hormones. Older adults (61.3 ± 1.5 yr; 33.2 ± 1.1 kg/m2) with prediabetes (ADA criteria) were randomized to undertake 60 min of work-matched continuous (CONT, n = 14) or interval (INT, n = 14) exercise for 2 wks. During a 180 min 75-g OGTT, a number of aortic waveforms (applanation tonometry) were assessed: the augmentation pressure (AP) and index (AIx75), brachial (bBP) and central blood pressure (cBP), pulse pressure (bPP and cPP), pulse pressure amplification (PPA), and forward (Pf) and backward pressure (Pb) waveforms. Acylated-ghrelin (AG), des-acylated ghrelin (dAG), GIP, and GLP-1active were measured, and correlations were co-varied for insulin. Independent of intensity, exercise increased VO2peak (p = 0.01) and PPA120min (p = 0.01) and reduced weight (p < 0.01), as well as AP120min (p = 0.02) and AIx75120min (p < 0.01). CONT lowered bSBP (p < 0.02) and bDBP (p < 0.02) tAUC180min more than INT. There were decreases dAG0min related to Pb120min (r = 0.47, p = 0.03), cPP120min (r = 0.48, p = 0.02), and AP120min (r = 0.46, p = 0.02). Declines in AG tAUC60min correlated with lower Pb120min (r = 0.47, p = 0.03) and cPP120min (r = 0.49, p = 0.02) were also found. GLP-1active 0min was reduced associated with lowered AP180min (r = 0.49, p = 0.02). Thus, while CONT exercise favored blood pressure, both intensities of exercise improved aortic waveforms in relation to gut hormones after controlling for insulin.

Neural network methods for diagnosing patient conditions from cardiopulmonary exercise testing data

Background

Cardiopulmonary exercise testing (CPET) provides a reliable and reproducible approach to measuring fitness in patients and diagnosing their health problems. However, the data from CPET consist of multiple time series that require training to interpret. Part of this training teaches the use of flow charts or nested decision trees to interpret the CPET results. This paper investigates the use of two machine learning techniques using neural networks to predict patient health conditions with CPET data in contrast to flow charts. The data for this investigation comes from a small sample of patients with known health problems and who had CPET results. The small size of the sample data also allows us to investigate the use and performance of deep learning neural networks on health care problems with limited amounts of labeled training and testing data.

Methods

This paper compares the current standard for interpreting and classifying CPET data, flowcharts, to neural network techniques, autoencoders and convolutional neural networks (CNN). The study also investigated the performance of principal component analysis (PCA) with logistic regression to provide an additional baseline of comparison to the neural network techniques.

Results

The patients in the sample had two primary diagnoses: heart failure and metabolic syndrome. All model-based testing was done with 5-fold cross-validation and metrics of precision, recall, F1 score, and accuracy. As a baseline for comparison to our models, the highest performing flow chart method achieved an accuracy of 77%. Both PCA regression and CNN achieved an average accuracy of 90% and outperformed the flow chart methods on all metrics. The autoencoder with logistic regression performed the best on each of the metrics and had an average accuracy of 94%.

Conclusions

This study suggests that machine learning and neural network techniques, in particular, can provide higher levels of accuracy with CPET data than traditional flowchart methods. Further, the CNN performed well with a small data set showing that these techniques can be designed to perform well on small data problems that are often found in health care and the life sciences. Further testing with larger data sets is needed to continue evaluating the use of machine learning to interpret CPET data.

Circadian secretion rhythm of GLP-1 and its influencing factors

Circadian rhythm is an inherent endogenous biological rhythm in living organisms. However, with the improvement of modern living standards, many factors such as prolonged artificial lighting, sedentarism, short sleep duration, intestinal flora and high-calorie food intake have disturbed circadian rhythm regulation on various metabolic processes, including GLP-1 secretion, which plays an essential role in the development of various metabolic diseases. Herein, we focused on GLP-1 and its circadian rhythm to explore the factors affecting GLP-1 circadian rhythm and its potential mechanisms and propose some feasible suggestions to improve GLP-1 secretion.

Effect of exercise training interventions on energy intake and appetite control in adults with overweight or obesity: A systematic review and meta-analysis

This systematic review examined the impact of exercise training interventions on energy intake (EI) and appetite control in adults with overweight/obesity (≥18 years including older adults). Articles were searched up to October 2019. Changes in EI, fasting appetite sensations, and eating behavior traits were examined with random effects meta-analysis, and other outcomes were synthesized qualitatively. Forty-eight articles were included (median [range] BMI = 30.6 [27.0-38.4] kg/m² ). Study quality was rated as poor, fair, and good in 39, seven, and two studies, respectively. Daily EI was assessed objectively (N = 4), by self-report (N = 22), with a combination of the two (N = 4) or calculated from doubly labeled water (N = 1). In studies rated fair/good, no significant changes in pre-post daily EI were found and a small but negligible (SMD < 0.20) postintervention difference when compared with no-exercise control groups was observed (five study arms; MD = 102 [1, 203] kcal). There were negligible-to-small pre-post increases in fasting hunger and dietary restraint, decrease in disinhibition, and some positive changes in satiety and food reward/preferences. Within the limitations imposed by the quality of the included studies, exercise training (median duration of 12 weeks) leads to a small increase in fasting hunger and a small change in average EI only in studies rated fair/good. Exercise training may also reduce the susceptibility to overconsumption (PROSPERO: CRD42019157823).

Psychobiology of Appetite and Food Reward in Adults with Type 1 and Type 2 Diabetes: Is there a Role for Exercise?

Hyperglycemia is the defining feature of type 1 diabetes (T1D) and type 2 diabetes (T2D) and results from deficient insulin production, impaired insulin-stimulated glucose uptake or both. It is now well established that hyperglycemia results in profound metabolic complications, but the effect of diabetes and its associated metabolic effects on homeostatic and hedonic appetite control has received less attention. Inappropriate food choices and excess food intake might promote weight gain, further exacerbating the metabolic consequences of T1D and T2D. The need to control blood glucose through diet, physical activity and/or medication as a consequence of impaired insulin secretion and/or sensitivity adds a further level of physiological and behavioural complexity to the processes underlying food choice and appetite control. Alterations in appetite-related processes have been noted in people with T2D, but the effect of T1D on appetite is largely unexplored. Peripheral neuroendocrine signalling appears disrupted in people with T2D, and brain regions involved in the central modulation of appetite might display central insulin resistance. However, it is difficult to isolate the consequences of T2D from those of obesity. Health-care policy advocates the use of physical activity as a means of preventing and treating T2D via the promotion of weight loss and its independent influence on insulin sensitivity. Exercise-induced perturbations to energy balance can elicit biological and behavioural compensation that attenuates weight loss, and diabetes pathophysiology might alter the strength of such compensation. However, the effect of exercise on appetite in people living with diabetes has yet to be fully explored.

Short-term interval exercise suppresses acylated ghrelin and hunger during caloric restriction in women with obesity

Caloric restriction is suggested to increase hunger, in part, through complex interactions of hormones and behavior that contribute to challenges in long-term weight loss. Although intense exercise may attenuate appetite, no data exist testing the effects of interval exercise (INT) during a low-calorie diet (LCD) on appetite regulation. We hypothesized that LCD+INT would favorably influence satiety when compared with an energy-deficit matched LCD in women with obesity. Twenty-six women with obesity (47.3±2.4 yrs; 37.3 ± 1.2 kg/m2) were randomized to either LCD (n = 13; mixed meals of ~1200 kcal/d) or LCD+INT (n = 13; 60 min/d of supervised interval exercise at 90% HRpeak for 3 min and 50% HRpeak for 3 min) for 2 weeks. An additional 350kcal (shake) was provided to LCD+INT individuals post-exercise to equate energy availability between groups. Total PYY, acylated ghrelin and des-ghrelin were measured at 0, 30 and 60 min of a 75g OGTT before and after the intervention. Visual analog scales were also administered at 0 and 120 min of the OGTT to assess appetite perception. Food logs were recorded prior to and during the intervention to ensure caloric intake compliance. Compared with pre-intervention conditions, both interventions decreased food intake (P = 0.001) and body fat (P < 0.01). There was no effect on fasting PYY, but both LCD and LCD+INT increased post-prandial PYY iAUC (P < 0.001) relative to pre-intervention. LCD+INT maintained fasting acylated ghrelin (P = 0.06) and suppressed post-prandial acylated ghrelin iAUC (P = 0.04) compared to LCD. Neither intervention impacted circulating des- ghrelin before or following the OGTT. Interestingly, LCD+INT attenuated fasting hunger and maintained fullness compared with LCD (P = 0.05 and P = 0.06, respectively). Taken together, interval exercise favors acylated ghrelin suppression and perception of hunger during a LCD in women with obesity.

Exercise improves adiposopathy, insulin sensitivity and metabolic syndrome severity independent of intensity

NEW FINDINGS

What is the central question of this study? What are the effects of work-matched continuous versus high-intensity interval training for 2 weeks on adiposopathy and cardiometabolic risk in obese adults with prediabetes? What is the main finding and its importance? Independent of intensity, short-term exercise improves adiposopathy and insulin sensitivity. While both exercise intensities reduced fasting leptin concentrations and metabolic syndrome severity, only interval training elevated total adiponectin. In contrast to previous work, neither condition altered high-molecular weight adiponectin. Collectively, these data suggest that short-term exercise can improve adipokine profiles, which may aid in reducing cardiometabolic risk prior to clinically meaningful weight loss in adults with prediabetes.

ABSTRACT

Individuals with prediabetes who are overweight and obese are at an increased risk of developing endocrine disruption of fat tissue, known as adiposopathy. While short-term exercise improves adipokine profiles, the effects of exercise intensity when matched for energy expenditure on adiposopathy are unknown. We hypothesized that high-intensity exercise would elicit greater changes in adiposopathy compared to moderate exercise. Twenty-eight overweight and obese adults (age: 60.9 ± 8.4 years; BMI: 33.0 ± 5.4 kg m-2 ) with prediabetes were randomized to twelve 60-min sessions of either moderate-continuous (CONT; n = 14) or high-intensity interval (INT; n = 14) exercise training. Total and high molecular weight (HMW) adiponectin and leptin were collected to assess adiposopathy (ratio of total adiponectin to leptin; A/L). Insulin sensitivity (SIIS ) was determined using a 75 g oral glucose tolerance test before and after training. Cardiometabolic risk factors were measured and a z-score was calculated to determine metabolic syndrome (MetS) severity. CONT and INT increased A/L (P < 0.01) and decreased leptin (P < 0.01) and MetS severity (P = 0.04). Neither intervention altered circulating levels of HMW adiponectin (P = 0.76) and only INT increased total adiponectin levels (P = 0.02). Both intensities increased insulin sensitivity (P < 0.01), which was associated with improvements in A/L (r = 0.47, P = 0.01). Additionally, increases in A/L tended to relate to decreased MetS severity (r = -0.36, P = 0.09). Short-term exercise intensity, when matched for energy expenditure, does not differentially affect improvements in adiposopathy in overweight and obese adults with prediabetes. Further, 12 bouts of exercise improved insulin sensitivity and MetS severity, suggesting that improving adipokine profiles may aid in reducing cardiometabolic risk.