Supervised exercise in patients with impaired fasting glucose: impact on exercise capacity

Exercise training modalities in prediabetes: a systematic review and network meta-analysis

Background

Lifestyle modification based on exercise intervention is still the primary way to delay or reverse the development of diabetes in patients with prediabetes. However, there are still challenges in setting up a detailed exercise prescription for people with prediabetes. This study mainly ranks exercise prescriptions by comparing the improvement of glucose and lipid metabolism and the level of weight loss in patients.

Method

All studies on exercise intervention in prediabetes were identified by searching five electronic databases. Risk assessment and meta-analysis were performed on eligible studies.

Results

Twenty-four studies involving 1946 patients with prediabetes and seven exercise intervention models were included in the final analysis. The meta-analysis showed that exercise of any type was more effective for glycemic control in prediabetes than no exercise. However, the changes in blood glucose were moderate. In prediabetes, combining moderate-intensity aerobic exercise with low-to moderate-load resistance training showed the most significant improvements in glycosylated hemoglobin (HbA1c), body mass index (BMI), body weight (BW), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL) (P-score=0.82; 0.70; 0.87; 1; 0.99), low-to moderate-load resistance training showed the most significant improvements in fasting blood glucose (FBG) (P-score=0.98), the vigorous-intensity aerobic exercise showed the most significant improvements in 2-hour post-meal blood glucose (2hPG) and systolic blood pressure (SBP) (P-score=0.79; 0.78), and moderate-intensity aerobic exercise showed the most significant improvements in diastolic blood pressure (DBP) (P-score=0.78).

Conclusion

In summary, moderate-intensity aerobic exercise, low-to moderate-load resistance training and the combination of both have beneficial effects on glycemic control, weight loss, and cardiovascular health in patients with prediabetes. These findings provide valuable guidance for rehabilitation clinicians and patients alike to follow.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD 42021284922.

Lower-Intensity Interventions for Prediabetes: A Systematic Review

INTRODUCTION

Systematic reviews of interventions for diabetes prevention have focused on lifestyle interventions, including the Diabetes Prevention Program (DPP) and translations of the DPP. However, nationally, few people with prediabetes have joined or completed a DPP, with one cited barrier being committing to a yearlong program. This study was a systematic review to evaluate the effectiveness of lower-intensity lifestyle interventions for prediabetes on weight change, glycemia, and health behaviors.

METHODS

English-language studies from PubMed, Embase, PsycINFO, and CINAHL from 2000 to February 23, 2022 were searched for RCTs of nonpregnant adults with prediabetes and elevated BMI and lower-intensity interventions (defined as ≤12 months and <14 sessions over 6 months). Two reviewers independently identified 11 trials, assessed study quality (using Cochrane risk-of-bias tool), and extracted data serially. A qualitative synthesis was conducted by outcome.

RESULTS

Only 1 of 11 trials of lower-intensity interventions was of high quality (>80% follow-up rate and low risk of bias). This 6-month study compared an app with standardized dietary advice, showing a 3-kg greater body weight reduction and 0.2% greater reduction of HbA1c.

DISCUSSION

The evidence on lower-intensity lifestyle interventions for diabetes prevention is limited by the small number and methodologic weaknesses of previous trials, and future research is needed in this area. Given the low uptake of and retention in evidence-based high-intensity programs, future work is needed to investigate the effectiveness of novel lower-intensity interventions offered with established DPP content of varying duration and intensity.

Effect of physical activity and different exercise modalities on glycemic control in people with prediabetes: a systematic review and meta-analysis of randomized controlled trials

Background

Numerous studies have shown the beneficial effects of exercise on glycemic control in people with prediabetes. However, the most effective exercise modality for improving glycemic control remains unclear. We aimed to assess which exercise training modality is most effective in improving glycemic control in a population with prediabetes.

Methods

We conducted searches in Pubmed/MEDLINE, EMBASE, SPORTDiscus, Web of Science, PEDro, BVS, and the Cochrane Library from inception to June 2022. Included studies reported fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), and 2-hour postprandial (2hPP) levels and implemented an exercise program lasting at least 12 weeks in adults with prediabetes. We performed a direct meta-analysis using a random-effects model and a network meta-analysis. Cochran's Q statistic and the inconsistency I2 test were used to assess the heterogenicity between studies.

Results

Twenty trials were included, with 15 trials (comprising 775 participants with prediabetes) combined in the meta-analysis, and 13 in the network meta-analysis. The meta-analysis results did not show a statistically significant reduction in fasting plasma glucose (FPG) after aerobic training (AT) intervention compared to a control group (mean (95%CI) difference = -5.18 (-13.48; 3.12) mg/dL, Z=1.22, p=0.22). However, a difference of -7.25 (-13.79; -0.71) mg/dL, p=0.03, in FPG after interval training (IT) intervention was detected compared to a control group. After resistance training (RT) intervention, FPG was significantly lower -6.71 (-12.65,-0.77) mg/dL, Z=2.21, p=0.03, and HbA1c by -0.13 (-0.55, 0.29), p=0.54, compared to the control group. The impact of RT compared to no intervention on 2hPP was not statistically significant (p=0.26). The network meta-analysis did not show statistical significance. Most of the studies presented an unclear risk of bias, and a low and very low-quality of evidence. According to the GRADE criteria, the strength of the body of evidence was low.

Conclusion

Resistance training and IT had demonstrated benefits on glycemic indices, especially on FPG, in a population with prediabetes. Further studies with larger sample sizes and a more robust methodology that compare different types of exercise modalities, frequencies, and durations, are needed to establish a beneficial exercise intervention.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=370688, identifier CRD42022370688.

Differential Effects of Amount, Intensity, and Mode of Exercise Training on Insulin Sensitivity and Glucose Homeostasis: A Narrative Review

As type 2 diabetes remains a leading cause of morbidity and mortality, identifying the most appropriate preventive treatment early in the development of disease is an important public health matter. In general, lifestyle interventions incorporating exercise and weight loss via caloric restriction improve cardiometabolic risk by impacting several key markers of insulin sensitivity and glucose homeostasis. However, variations in the effects of specific types of exercise interventions on these markers have led to conflicting results surrounding the optimal amount, intensity, and mode of exercise for optimal effects. Moreover, the addition of weight loss via caloric restriction to exercise interventions appears to differentially impact changes in body composition, metabolism, and insulin sensitivity compared to exercise alone. Determining the optimal amount, intensity, and mode of exercise having the most beneficial impact on glycemic status is both: (1) clinically important to provide guidelines for appropriate exercise prescription; and (2) physiologically important to understand the pathways by which exercise—with and without weight loss—impacts glycemic status to enhance precision lifestyle medicine. Thus, the purposes of this narrative review are to: (1) summarize findings from the three Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) randomized trials regarding the differential effects of exercise amount, intensity, and mode on insulin action and glucose homeostasis markers; and (2) compare the STRRIDE findings to other published dose–response exercise trials in order to piece together the various physiologic pathways by which specific exercise interventions—with or without weight loss—impact glycemic status.

Effects of Regular Long-Term Circuit Training (Once per Week) on Cardiorespiratory Fitness in Previously Sedentary Adults

The purpose of the study was (1) to investigate the effects of regular long-term circuit training (once per week) on cardiorespiratory fitness (CRF) in sedentary adults and (2) to compare training progress with the effects of continued exercise participation by regularly active age-matched individuals. Ten sedentary, middle-aged (51 ± 6 years) individuals (sedentary group, SG) of both sexes performed 32 weeks (1 training session/week) of supervised circuit training and 10 weeks of self-managed training. Effects were compared to an age-matched group (51 ± 8 years; n = 10) of regularly active individuals (active group, AG). CRF (expressed as peak oxygen uptake: VO₂peak; peak power output: PPO) and systemic blood pressure (BP) during the incremental test were measured at the start and after the training intervention. CRF decreased significantly within the AG (VO₂peak: 43.1 ± 7.3 vs. 40.3 ± 6.5 mL/min/kg, p < 0.05; PPO: 3.3 ± 0.6 vs. 3.1 ± 0.6; p < 0.05) but was maintained in the SG. In addition, significant improvements in restoration of the oxygen level in leg muscles after exercise and reduced systolic BP (180 ± 14 vs. 170 ± 17 mmHg, p = 0.01) at submaximal exercise were found within the SG. However, differences in changes from pre to post did not reach significance between groups. In contrast to the regularly active individuals, circuit training once per week over 32 weeks prevented the aging-related decline of CRF in previously sedentary subjects and reduced systolic BP during submaximal exercise, indicating improved exercise tolerance.

Comparisons of different exercise interventions on glycemic control and insulin resistance in prediabetes: a network meta-analysis

BACKGROUND

In order to recommend the optimal type of exercise for type 2 diabetes prevention, different exercise interventions were compared with respect to their effects on glycemic control and insulin resistance.

METHODS

Studies on the curative effect of aerobic exercise training (AET), resistance training (RT), or control training (CT) on prediabetes were retrieved from the PubMed, Embase, SPORTDiscus, and Cochrane Library databases. Body mass index (BMI); homeostasis model assessment of insulin resistance index (HOMA-IR); and fasting blood glucose (FBG), glycated hemoglobin (HbA1c), and insulin levels were used as outcome indicators. The Q statistic was calculated to evaluate heterogeneity within studies. A fixed- or random-effects model was used for pooling data based on nonsignificant or significant heterogeneities. A consistency test was conducted using a node-splitting analysis.

RESULTS

A total of 13 eligible studies were included. The results of the direct meta-analysis indicated that AET or RT could significantly reduce the HbA1c level in prediabetic individuals compared to CT [AET vs. CT: standardized mean difference (SMD) = - 0.6739, 95% confidence interval (CI) = - 0.9424 to - 0.4055 to RT vs. CT: SMD = - 1.0014, 95% CI = - 1.3582 to - 0.6446]. The findings from the network meta-analysis showed that there were no statistical differences among the four comparisons for all the indicators except for lower HbA1c level (SMD = - 0.75, 95% CI = - 1.31 to - 0.19) and HOMA-IR (SMD = - 1.03, 95% CI = - 1.96 to - 0.10) in the AET group than in the CT group. In addition, prediabetic individuals in the AET + RT group showed greater control of BMI and insulin and FBG levels than those in the other groups, whereas AET was the most effective in controlling HbA1c and HOMA-IR levels in prediabetic individuals.

CONCLUSION

AET, AET + RT, and RT exerted beneficial effects on insulin resistance and glycemic control in prediabetic patients. From the existing data, AET or AET + RT is preferentially recommended for these patients, although further studies may unveil RT as a promising therapy. Benefits from all types of exercise seem to occur in an intensity-dependent manner.

A scoping review of exercise referral schemes involving qualified exercise professionals in primary health care

Qualified exercise professionals (QEPs) have the training, knowledge, and scope of practice to effectively provide physical activity counselling, prescribe exercise, and deliver exercise programming to patients with or without chronic diseases. Healthcare providers identify an interest in referring patients to QEPs; however, the impact of exercise referral schemes (ERS) involving QEPs on patients' physical health is unclear. A scoping review regarding the available evidence of ERS involving healthcare provider referrals to QEPs was performed. A literature search was conducted in 6 databases (initially: n = 6011 articles), yielding n = 23 articles examining QEP delivered physical activity counselling (n = 7), QEP supervised exercise training (n = 4), or some combination (n = 12). Although studies were heterogeneous in methods, procedures, and populations, ERSs increased patients' subjective physical activity levels. Few studies incorporated objective physical activity measures (n = 5/23), and almost half measured aerobic fitness (n = 11/23). ERS involving a QEP that includes activity counselling and/or exercise programming/training report favourable impacts on patients' subjectively measured physical activity and objectively measured aerobic fitness. Based on the existing literature on the topic, this scoping review provides recommendations for designing and evaluating ERS with QEPs that include: objective measures, long-term follow-up, QEP qualifications, and the cost-effectiveness of ERS. Novelty: ERS involving QEPs report increased patients' perceived physical activity level and may improve patients' cardiorespiratory fitness. Promoting the collaboration of QEPs with other healthcare providers can enhance patients' physical fitness and health. This scoping review provides recommendations for the design and evaluation of ERS involving QEPs.

Two-year-supervised resistance training prevented diabetes incidence in people with prediabetes: A randomised control trial

AIM

The purpose of this study is to explore the long-term effects of aerobic training (AT), resistance training (RT), and combined training (AT + RT) on the prevention of T2D incidence in patients with prediabetes.

MATERIALS AND METHODS

In this randomised controlled trial, people with prediabetes (fasting glucose ≥5.6 and <7.0 mmol/L and/or 2-h glucose ≥7.8 and <11.1 mmol/L on the 75-g oral glucose tolerance test and/or haemoglobin A_1c ≥5.7% and <6.4%) were randomly assigned to the control group, AT group, RT group, or AT + RT group. Supervised exercise programmes, including AT, RT, and AT + RT, were completed for 60 minutes per day, three non-consecutive days per week for 24 months. The primary outcome was the incidence of T2D; secondary outcomes were blood glucose and lipid levels, including total cholesterol (TC) and standard 2-hour oral glucose tolerance (2hPG).

RESULTS

A total of 137 (80%) subjects with a mean age of 59 years (45 men, 92 women) entered the final analysis. After 24 months of intervention, the incidences of T2D adjusted by sex and age were significantly decreased by 74% (95% CI, 38-89), 65% (95% CI, 21-85), and 72% (95% CI, 36-87) in the AT + RT, RT, and AT groups compared with the control group (HR: AT + RT 0.26 [95% CI, 0.11-0.62], RT 0.35 [95% CI, 0.15-0.79], and AT 0.28 [95% CI, 0.13-0.64]). The cumulative T2D incidences were significantly lower in the AT + RT, RT, and AT groups than in the control group (21%, 26%, and 22% vs 69%). The blood glucose and lipid profiles improved more in the AT, RT, and AT + RT groups than in the control group.

CONCLUSION

RT and RT plus AT were as effective as isolated AT in preventing progression to T2D.

Inter-individual differences in weight change following exercise interventions: a systematic review and meta-analysis of randomized controlled trials

Previous reports of substantial inter-individual differences in weight change following an exercise intervention are often based solely on the observed responses in the intervention group. Therefore, we aimed to quantify the magnitude of inter-individual differences in exercise-mediated weight change. We synthesized randomized controlled trials (RCTs) of structured, supervised exercise interventions. Fourteen electronic databases were searched for relevant studies published up to March 2017. Search terms focused on structured training, RCTs and body weight. We then sifted these results for those RCTs (n = 12, 1500 participants) that included relevant comparator group data. Standard deviations (SDs) of weight change were extracted, thereby allowing the SD for true inter-individual differences in weight loss to be calculated for each study. Using a random effects meta-analysis, the pooled SD (95% CI) for true individual responses was 0.8 (-0.9 to 1.4) kg. The 95% prediction interval (based on 2SDs) for true inter-individual responses was -2.8 to 3.6 kg. The probability (% chance) that the true individual response variability would be clinically meaningful (>2.5 kg) in a future study in similar settings was 23% ('unlikely'). Therefore, we conclude that evidence is limited for the notion that there are clinically important individual differences in exercise-mediated weight change.

Different training responses to eccentric endurance exercise at low and moderate altitudes in pre-diabetic men: a pilot study

This pilot study aimed (a) to evaluate the effects of eccentric exercise training at low and moderate altitudes on physical fitness in pre-diabetic men and (b) to establish whether or not oxidative stress levels and antioxidant status were associated with performance improvements. In this crossover trial, five pre-diabetic men conducted nine downhill walking sessions (3 days/week, 3 consecutive weeks) at low altitude (from 1360 to 850 m) and one year later at moderate altitude (from 2447 to 2000 m). Exercise testing and the determination of parameters of oxidative stress and antioxidant capacity were performed pre- and post-training. The biological antioxidant activity of plasma (BAP) increased after eccentric training at moderate altitude (p < 0.001), whereas diacron reactive oxygen metabolites (dROMs) remained unchanged. Also, the BAP/dROMs ratio increased only after training at moderate-altitude training (p = 0.009). Maximum power output improved after training at low altitude and the changes were significantly related to baseline BAP/dROMs ratio (r = 0.90). No decrease was seen for fasting plasma glucose. Eccentric exercise training in pre-diabetic men improved performance only when performed at low altitude and this improvement was positively related to the baseline BAP/dROMs ratio. In contrast, 3 weeks of eccentric exercise training increased BAP levels and the BAP/dROMs ratio only at moderate altitude without improving the performance. Thus, one might speculate that the BAP/dROMs ratio has to increase before performance improvements occur at moderate altitude.

Effect of lifestyle interventions on cardiovascular risk factors among adults without impaired glucose tolerance or diabetes: A systematic review and meta-analysis

Structured lifestyle interventions can reduce diabetes incidence and cardiovascular disease (CVD) risk among persons with impaired glucose tolerance (IGT), but it is unclear whether they should be implemented among persons without IGT. We conducted a systematic review and meta-analyses to assess the effectiveness of lifestyle interventions on CVD risk among adults without IGT or diabetes. We systematically searched MEDLINE, EMBASE, CINAHL, Web of Science, the Cochrane Library, and PsychInfo databases, from inception to May 4, 2016. We selected randomized controlled trials of lifestyle interventions, involving physical activity (PA), dietary (D), or combined strategies (PA+D) with follow-up duration ≥12 months. We excluded all studies that included individuals with IGT, confirmed by 2-hours oral glucose tolerance test (75g), but included all other studies recruiting populations with different glycemic levels. We stratified studies by baseline glycemic levels: (1) low-range group with mean fasting plasma glucose (FPG) <5.5mmol/L or glycated hemoglobin (A1C) <5.5%, and (2) high-range group with FPG ≥5.5mmol/L or A1C ≥5.5%, and synthesized data using random-effects models. Primary outcomes in this review included systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and triglycerides (TG). Totally 79 studies met inclusion criteria. Compared to usual care (UC), lifestyle interventions achieved significant improvements in SBP (-2.16mmHg[95%CI, -2.93, -1.39]), DBP (-1.83mmHg[-2.34, -1.31]), TC (-0.10mmol/L[-0.15, -0.05]), LDL-C (-0.09mmol/L[-0.13, -0.04]), HDL-C (0.03mmol/L[0.01, 0.04]), and TG (-0.08mmol/L[-0.14, -0.03]). Similar effects were observed among both low-and high-range study groups except for TC and TG. Similar effects also appeared in SBP and DBP categories regardless of follow-up duration. PA+D interventions had larger improvement effects on CVD risk factors than PA alone interventions. In adults without IGT or diabetes, lifestyle interventions resulted in significant improvements in SBP, DBP, TC, LDL-C, HDL-C, and TG, and might further reduce CVD risk.

Effect of lifestyle interventions on glucose regulation among adults without impaired glucose tolerance or diabetes: A systematic review and meta-analysis

This study systematically assessed the effectiveness of lifestyle interventions on glycemic indicators among adults (⩾18years) without IGT or diabetes. Randomized controlled trials using physical activity (PA), diet (D), or their combined strategies (PA+D) with follow-up ⩾12months were systematically searched from multiple electronic-databases between inception and May 4, 2016. Outcome measures included fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), fasting insulin (FI), homeostasis model assessment-estimated insulin resistance (HOMA-IR), and bodyweight. Included studies were divided into low-range (FPG <5.5mmol/L or HbA1c <5.5%) and high-range (FPG ⩾5.5mmol/L or HbA1c ⩾5.5%) groups according to baseline glycemic levels. Seventy-nine studies met inclusion criteria. Random-effect models demonstrated that compared with usual care, lifestyle interventions achieved significant reductions in FPG (-0.14mmol/L [95%CI, -0.19, -0.10]), HbA1c (-0.06% [-0.09, -0.03]), FI (%change: -15.18% [-20.01, -10.35]), HOMA-IR (%change: -22.82% [-29.14, -16.51]), and bodyweight (%change: -3.99% [-4.69, -3.29]). The same effect sizes in FPG reduction (0.07) appeared among both low-range and high-range groups. Similar effects were observed among all groups regardless of lengths of follow-up. D and PA+D interventions had larger effects on glucose reduction than PA alone. Lifestyle interventions significantly improved FPG, HbA1c, FI, HOMA-IR, and bodyweight among adults without IGT or diabetes, and might reduce progression of hyperglycemia to type 2 diabetes mellitus.

The influence of intensive lifestyle intervention on patients with isolated impaired fasting glucose: a meta-analysis

AIM

To evaluate the effect of intensive lifestyle intervention on patients with isolated impaired fasting glucose.

BACKGROUND

The application of lifestyle intervention to clinical nursing can help improve outcomes of patients with impaired fasting glucose.

DESIGN

We performed a meta-analysis of randomized controlled trials using methods outlined in the Cochrane Handbook.

METHODS

We performed keyword searches of the literature databases up to September 2014 and performed manual searches of selected article reference lists. Data were extracted by the lead reviewer, cross-checked by the second reviewer, entered into RevMan5·3, and pooled and analysed using the fixed effect inverse-variance model or random effects model to determine the mean difference and calculate the weighted mean difference. The heterogeneity statistic (I² ), overall effect (Z) and P-value were calculated.

RESULTS

A total of five studies were included in our analysis. Following the heterogeneity test statistic, overall effect Z score with P-value was calculated. The targets of fasting plasma glucose, weight, body mass index, triglycerides, high-density lipoprotein cholesterol and total cholesterol all showed significant differences between the intervention and control groups.

CONCLUSION

Lifestyle intervention can improve glycaemic control in patients with isolated impaired fasting glucose. It also reduces blood-lipid levels and promotes weight loss. Larger patient cohorts and adequate follow-up should be included in future trials.

Effect of weekly hiking on cardiovascular risk factors in the elderly

BACKGROUND

Hiking is one of the most popular activities among the elderly in Alpine regions. Due to the long-lasting, moderately intensive nature of this form of physical activity, hiking is generally considered to be beneficial to health. However, it is currently unclear whether once-weekly hiking--as commonly practiced at weekends--really does yield such positive effects in elderly persons aged 60 years and over.

OBJECTIVES

This study investigated the effect of a single weekly mountain hiking session on cardiovascular risk factors.

MATERIALS AND METHODS

A 9-month mountain hiking program was completed by 14 male (age 65.6 ± 2.7 years) and 10 female (age 66.2 ± 4.4 years) elderly participants. The program consisted of a single weekly hiking session with the goal of achieving a 500-m altitude increase within 3 h. Before and after the 9-month program, an electrocardiogram (ECG) was performed and blood pressure, glycated hemoglobin (HbA1c), high-density (HDL) and low-density lipoprotein (LDL) measurements were made.

RESULTS

The elderly participants showed a normal cardiovascular risk profile at the start of the investigation. The estimated net energy expenditure for one hiking session was approximately 521 ± 91 kcal. Over the 9-month period, no changes were found in any of the investigated parameters for the entire group. However, participants with untreated hypertension showed a reduced systolic blood pressure.

CONCLUSION

The present investigation showed that moderate-intensity activity only at weekends does not improve cardiovascular risk factors in elderly persons with a relatively normal cardiovascular risk profile. Conversely, elderly persons suffering from hypertension might profit from such a practice.

Normobaric Intermittent Hypoxia over 8 Months Does Not Reduce Body Weight and Metabolic Risk Factors--a Randomized, Single Blind, Placebo-Controlled Study in Normobaric Hypoxia and Normobaric Sham Hypoxia

OBJECTIVE

Both a 1- to 4-week continuous or intermittent stay and moderate exercise in hypoxia versus normoxia can lead to weight loss. We examined the reproducibility and durability of added hypoxic exposure in a feasible health program of several months.

METHODS

32 obese persons, randomly assigned to either a hypoxia (age 50.3 ± 10.3 years, BMI 37.9 ± 8.1 kg/m(²)) or a normoxia (age 52.4 ± 7.9 years, BMI 36.3 ± 4.0 kg/m(²)) group, completed 52 exercise sessions within 8 months. Participants exercised for 90 min (65-70% HR(peak)) either at a simulated altitude of 3,500 m or in normoxia, and rested for further 90 min at 4,500 m or normoxia. Before, after 5 weeks, after 3 months, and after the intervention, body composition and exercise capacity were determined. Risk markers (e.g., blood pressure, cholesterol) were measured before, after 3 months, and after the intervention period.

RESULTS

Body weight, BMI, waist and hip circumference, P(peak) and BP(sys) improved over time (p < 0.05) but without group difference. Fat mass reductions correlated with HDL changes (r = -0.427; p < 0.05) in the entire group.

CONCLUSION

Long-term, moderate intensity exercise and rest in hypoxia does not lead to higher reductions in body weight than normoxia alone. Therefore, for weight loss and metabolic markers hypoxic exposure does not add effects at least when stimuli (i.e., hypoxia dose, exercise intensity/duration) are unaltered throughout the intervention.

Efficacy of interventions that include diet, aerobic and resistance training components for type 2 diabetes prevention: a systematic review with meta-analysis

Current recommendations for the prevention of type 2 diabetes advise modification of diet and exercise behaviors including both aerobic and resistance training. However, the efficacy of multi-component interventions involving a combination of these three components has not been established. The aims of this review were to systematically review and meta-analyze the evidence on multi-component (diet + aerobic exercise + resistance training) lifestyle interventions for type 2 diabetes prevention. Eight electronic databases (Medline, Embase, SportDiscus, Web of Science, CINAHL, Informit health collection, Cochrane library and Scopus) were searched up to June 2013. Eligible studies 1) recruited prediabetic adults or individuals at risk of type 2 diabetes; 2) conducted diet and exercise [including both physical activity/aerobic and resistance training] programs; and 3) reported weight and plasma glucose outcomes. In total, 23 articles from eight studies were eligible including five randomized controlled trials, one quasi-experimental, one two-group comparison and one single-group pre-post study. Four studies had a low risk of bias (score ≥ 6/10). Median intervention length was 12 months (range 4-48 months) with a follow-up of 18 months (range 6.5-48 months). The diet and exercise interventions varied slightly in terms of their specific prescriptions. Meta-analysis favored interventions over controls for weight loss (-3.79 kg [-6.13, -1.46; 95% CI], Z = 3.19, P = 0.001) and fasting plasma glucose (-0.13 mmol.L⁻¹ [-0.24, -0.02; 95% CI], Z = 2.42, P = 0.02). Diabetes incidence was only reported in two studies, with reductions of 58% and 56% versus control groups. In summary, multi-component lifestyle type 2 diabetes prevention interventions that include diet and both aerobic and resistance exercise training are modestly effective in inducing weight loss and improving impaired fasting glucose, glucose tolerance, dietary and exercise outcomes in at risk and prediabetic adult populations. These results support the current exercise guidelines for the inclusion of resistance training in type 2 diabetes prevention, however there remains a need for more rigorous studies, with long-term follow-up evaluating program efficacy, muscular fitness outcomes, diabetes incidence and risk reduction.

Efficacy of interventions that include diet, aerobic and resistance training components for type 2 diabetes prevention: a systematic review with meta-analysis

Current recommendations for the prevention of type 2 diabetes advise modification of diet and exercise behaviors including both aerobic and resistance training. However, the efficacy of multi-component interventions involving a combination of these three components has not been established. The aims of this review were to systematically review and meta-analyze the evidence on multi-component (diet + aerobic exercise + resistance training) lifestyle interventions for type 2 diabetes prevention. Eight electronic databases (Medline, Embase, SportDiscus, Web of Science, CINAHL, Informit health collection, Cochrane library and Scopus) were searched up to June 2013. Eligible studies 1) recruited prediabetic adults or individuals at risk of type 2 diabetes; 2) conducted diet and exercise [including both physical activity/aerobic and resistance training] programs; and 3) reported weight and plasma glucose outcomes. In total, 23 articles from eight studies were eligible including five randomized controlled trials, one quasi-experimental, one two-group comparison and one single-group pre-post study. Four studies had a low risk of bias (score ≥ 6/10). Median intervention length was 12 months (range 4–48 months) with a follow-up of 18 months (range 6.5 - 48 months). The diet and exercise interventions varied slightly in terms of their specific prescriptions. Meta-analysis favored interventions over controls for weight loss (-3.79 kg [-6.13, -1.46; 95% CI], Z = 3.19, P = 0.001) and fasting plasma glucose (-0.13 mmol.L^-1 [-0.24, -0.02; 95% CI], Z = 2.42, P = 0.02). Diabetes incidence was only reported in two studies, with reductions of 58% and 56% versus control groups. In summary, multi-component lifestyle type 2 diabetes prevention interventions that include diet and both aerobic and resistance exercise training are modestly effective in inducing weight loss and improving impaired fasting glucose, glucose tolerance, dietary and exercise outcomes in at risk and prediabetic adult populations. These results support the current exercise guidelines for the inclusion of resistance training in type 2 diabetes prevention, however there remains a need for more rigorous studies, with long-term follow-up evaluating program efficacy, muscular fitness outcomes, diabetes incidence and risk reduction.

Life-style characteristics and cardiovascular risk factors in regular downhill skiers: an observational study

Background

Downhill skiing is part of active life style in many residents of Alpine regions. However, only very little information is available whether downhill skiing on a regular basis is associated with a healthier life style resulting in the reduction of major risk factors for cardiovascular diseases and memory deficits when compared to the general population. Thus, the aim of the study was to compare life-style characteristics and cardiovascular risk factors between regular downhill skiers and the general population.

Methods

Self-reported health and life-style data were collected by questionnaire from 1259 long-term downhill skiers (971 males, aged 57.3 ± 14.6 years; 288 females, aged 47.7 ± 16.4 years) and compared with data from the general population.

Results

Long-term skiers showed more favourable life-style characteristics and a better health status than the general population. Prevalences of hypercholesterolemia, systemic hypertension, diabetes, the frequency of mental stress and the occurrence of memory deficits declined with increasing yearly skiing frequency.

Conclusion

Long-term alpine skiing on a regular basis may contribute to healthy aging by its association with a healthier life style.

High cardiorespiratory fitness is more beneficial in pre-diabetic men than women

OBJECTIVES

To investigate gender-specific relationships between cardiorespiratory fitness and factors that predict the development of diabetes and to identify the risk factors that predict fasting plasma glucose and 2-hour plasma glucose levels.

INTRODUCTION

Different risk factors (e.g., low cardiorespiratory fitness) may cause elevated plasma glucose levels in men compared to women. Therefore, gender-specific analyses are needed.

METHODS

Cardiorespiratory fitness (maximal power output achieved during a standard cycle ergometry test), resting blood pressure, total serum cholesterol, high-density lipoprotein cholesterol and triglyceride levels were measured in 32 pre-diabetic men (mean age: 57.2 ± 6.8 years; mean body mass index (BMI): 28.5 ± 3.0 kg/m²) and 40 pre-diabetic women (mean age: 55.0 ± 7.3 years, mean BMI: 30.4 ± 5.7 kg/m²). A stepwise regression with backward variable selection was performed to construct models that predict 2-hour and fasting plasma glucose levels.

RESULTS

Maximal power output was inversely related to the 2-hour plasma glucose level in the entire group (r= -0.237, p<0.05), but this relationship was significant only for males (r= -0.404, p<0.05). No significant correlation was found between female gender and cardiorespiratory fitness. Age and cardiorespiratory fitness were significant predictors of 2-hour plasma glucose levels in men. High-density lipoprotein cholesterol was predictive of 2-hour plasma glucose levels in women. Triglycerides in women and BMI in men were the only predictors of fasting plasma glucose levels.

CONCLUSIONS

These findings may have consequences for the development of gender-specific diabetes prevention programs. Whereas increasing cardiorespiratory fitness should be a key goal for men, improving the lipid profile seems to be more beneficial for women. However, the present results do not negate the positive effects of increasing cardiorespiratory fitness in women.