Physical activity in prevention and treatment of the metabolic syndrome

The association of levels of physical activity with metabolic syndrome in rural Australian adults

Background

Physical activity (PA) reduces risk factors related to metabolic syndrome. Rurality influences the way people incorporate physical activity into daily life. The aim of this study is to determine the association of PA level with metabolic syndrome in a rural Australian population. The influence of adiposity on these associations is also investigated.

Methods

Three cross-sectional population health surveys were conducted in south-east Australia during 2004–2006 using a random population sample (n = 1563, participation rate 49%) aged 25–74 years. PA was assessed via a self-administered questionnaire, and components of the metabolic syndrome via anthropometric measurements taken by specially trained nurses and laboratory tests.

Results

Approximately one-fifth of participants were inactive in leisure-time and over one-third had metabolic syndrome (men 39%, women 33%; p = 0.022). There was an inverse association between level of PA and metabolic syndrome (p < 0.001). Men who were inactive in leisure-time were more than twice as likely and women more than three times as likely to have metabolic syndrome compared with those having high PA. Body mass index (BMI) is a mediating factor in the association between level of PA and metabolic syndrome.

Conclusion

Some PA is better than none if adults, particularly women, are to reduce their risk of metabolic syndrome and associated vascular diseases. Specialised interventions that take rurality into consideration are recommended for adults who are inactive.

The role of phosphoinositide 3-kinase and phosphatidic acid in the regulation of mammalian target of rapamycin following eccentric contractions

Resistance exercise induces a hypertrophic response in skeletal muscle and recent studies have begun to shed light on the molecular mechanisms involved in this process. For example, several studies indicate that signalling by the mammalian target of rapamycin (mTOR) is necessary for a hypertrophic response. Furthermore, resistance exercise has been proposed to activate mTOR signalling through an upstream pathway involving the phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB); however, this hypothesis has not been thoroughly tested. To test this hypothesis, we first evaluated the temporal pattern of signalling through PI3K-PKB and mTOR following a bout of resistance exercise with eccentric contractions (EC). Our results indicated that the activation of signalling through PI3K-PKB is a transient event (<15 min), while the activation of mTOR is sustained for a long duration (>12 h). Furthermore, inhibition of PI3K-PKB activity did not prevent the activation of mTOR signalling by ECs, indicating that PI3K-PKB is not part of the upstream regulatory pathway. These observations led us to investigate an alternative pathway for the activation of mTOR signalling involving the synthesis of phosphatidic acid (PA) by phospholipase D (PLD). Our results demonstrate that ECs induce a sustained elevation in [PA] and inhibiting the synthesis of PA by PLD prevented the activation of mTOR. Furthermore, we determined that similar to ECs, PA activates mTOR signalling through a PI3K-PKB-independent mechanism. Combined, the results of this study indicate that the activation of mTOR following eccentric contractions occurs through a PI3K-PKB-independent mechanism that requires PLD and PA.

Beneficial effects of individualized physical activity on prescription on body composition and cardiometabolic risk factors: results from a randomized controlled trial

BACKGROUND

Insufficient physical activity (PA), overweight and abdominal obesity are increasing global public health problems.

DESIGN

Randomized controlled 6-month intervention study.

METHODS

One hundred and one 68-year-old individuals (57% female) with low PA, overweight (BMI 25-40 kg/m) and abdominal obesity (waist circumference >88 cm in women and >102 cm in men), were randomized to PA on prescription (PAP) or a minimal intervention. PA measured by several methods, anthropometric parameters, body composition and cardiometabolic risk factors were measured at baseline and after intervention.

RESULTS

Favourable changes in anthropometrics, body composition, S-glucose, glycosolated haemoglobin (HbA1c), blood lipids and apolipoproteins were seen in the PAP group. In the control group, however, some positive changes were also noted. Bodyweight, neck circumference, fat mass, S-cholesterol and HbA1c decreased significantly more in the PAP group.

CONCLUSION

Individualized PAP improves body composition and cardiometabolic risk factors in sedentary older overweight individuals. PAP might be useful in clinical practice to counteract the epidemic of sedentary lifestyle and concomitant cardiometabolic disorders.

Comparison of aerobic exercise capacity and muscle strength in overweight women with and without polycystic ovary syndrome

OBJECTIVE

To assess maximal aerobic capacity (VO2max) and muscle strength in overweight and obese women with polycystic ovary syndrome (PCOS) and determine their relationship with metabolic and hormonal factors.

DESIGN

Cross-sectional study.

SETTING

Clinical Research Unit.

POPULATION

Overweight and obese women with PCOS (n = 10) and age-and weight-matched healthy controls (n = 16).

METHODS

VO2max was measured during an incremental treadmill test and maximal isometric (ImS) and isokinetic knee extensor strength (IkS) (120 degrees/second) were assessed by isokinetic dynamometry.

MAIN OUTCOME MEASURES

VO2max, ImS, IkS, waist circumference, blood lipids, glucose, insulin, insulin resistance (homeostatic model assessment [HOMA2]), C-reactive protein (CRP), hormonal profile.

RESULTS

PCOS women had higher levels of testosterone and free testosterone (P < or = 0.05), but there were no significant differences in any cardiovascular disease (CVD) risk markers between the groups. VO2max was similar in women with PCOS and healthy controls (PCOS 26.0 +/- 4.1 ml/kg/minute, controls 25.7 +/- 3.8 ml/kg/minute; P = 0.90), as was ImS (PCOS 1.50 +/- 0.54 Nm/kg, controls 1.50 +/- 0.47 Nm/kg; P = 0.96) and IkS (PCOS 1.04 +/- 0.32 Nm/kg, controls 1.16 +/- 0.23 Nm/kg; P = 0.32). VO2max was inversely related to waist circumference, insulin, HOMA2 and CRP. Waist circumference was inversely associated with ImS and IkS. No significant associations between exercise parameters and hormonal variables were identified.

CONCLUSIONS

Compared to age- and weight-matched healthy overweight and obese women with similar insulin resistance and CVD risk profiles, women with PCOS had similar aerobic capacity and muscle strength. This suggests PCOS, at least in the absence of an adverse metabolic profile is unlikely to limit physical function. Larger studies examining the effects of PCOS on exercise tolerance in a diverse range of PCOS phenotypes is required.

Comparable reduction of the visceral adipose tissue depot after a diet-induced weight loss with or without aerobic exercise in obese subjects: a 12-week randomized intervention study

OBJECTIVE

Weight loss with preferential effect on the visceral adipose tissue (VAT) depot could have important clinical benefits. In this study, we investigated the independent and combined effect of regular exercise and diet induced weight loss on body fat distribution. DESIGN; Randomized control design of i) exercise-only (EXO; 12 weeks of exercise without diet-restriction), ii) hypocaloric-diet (DIO; 8 weeks of very low energy diet (VLED 600 kcal/day) followed by 4-weeks weight maintenance diet) and iii) hypocaloric-diet and exercise (DEX; 8 weeks VLED 800 kcal/day+a 4-week weight maintenance diet combined with exercise throughout the 12 weeks).

SUBJECTS

Seventy-nine obese males and females were included.

MEASUREMENTS

Body fat distribution was quantified by magnetic resonance imaging (MRI)-technology.

RESULTS

In the EXO group, the weight loss (3.5 kg) and the relative reduction in VAT (18%) was significantly lower compared with the weight losses in the DIO and DEX groups (12.3 kg; P<0.01) and to the reduction in VAT (30-37%; P<0.01). In all the three groups, the relative reduction of VAT was higher as compared with the reduction in fat mass (FM; combining all fat depots determined by MRI; P<0.01 for all comparisons). The changes in VAT were associated with changes in FM and related to the initial VAT/FM ratio (r(2)=0.72; P<0.01).

CONCLUSION

Exercise has no additional effects in reduction of the VAT depot, compared with the major effects of hypocaloric diet alone. In addition, the effects of exercise per se on VAT are relatively limited. The effects on the VAT depot are closely associated with changes in total FM.

Prediction of leisure-time physical activity among obese individuals

The aims of this study were to identify (i) what cognitions predict leisure-time physical activity and (ii) the moderators of cognition-behavior relationships among obese individuals. A sample of 91 adults (BMI >or=30 kg/m(2)) completed a baseline questionnaire assessing variables of the theory of planned behavior (TPB). Biological measures and socio-demographic variables were also obtained. Behavior was assessed 3 months later. Multiple hierarchical regression analyses indicated that significant variables predicting behavior were past behavior (beta = 0.39; P = 0.0001), intention (beta = 0.27; P = 0.03), and the interaction term "perceived behavioral control (PBC) x perceived built environment" (beta = 0.17; P = 0.05). The PBC-behavior relation was better when the built environment was perceived as favorable to physical activity. The model explained 41% of variance in behavior. The determinants explaining intention were PBC (beta = 0.55; P < 0.0001), anticipated regret (beta = 0.26; P = 0.0007), and past behavior (beta = 0.22; P = 0.005), accounting for 59% of variance. Participation in leisure-time physical activity is explained primarily by a person's intentions to perform this behavior. The results also suggest that people are more able to translate their perception of control into action if they perceive the built environment as favorable, although this additional gain in prediction is small relative to intention. Nonetheless, both cognitions and aspects of the built environment should be given consideration in the promotion of leisure-time physical activity among obese individuals.

Body composition, fitness, and metabolic health during strength and endurance training and their combination in middle-aged and older women

In this study adaptations in body composition, physical fitness and metabolic health were examined during 21 weeks of endurance and/or strength training in 39- to 64-year-old healthy women. Subjects (n = 62) were randomized into endurance training (E), strength training (S), combined strength and endurance training (SE), or control groups (C). S and E trained 2 and SE 2 + 2 times in a week. Muscle strength and maximal oxygen uptake (VO(2)max) were measured. Leg extension strength increased 9 +/- 8% in S (P < 0.001), 12 +/- 8% in SE (P < 0.001) and 3 +/- 4% in E (P = 0.036), and isometric bench press 20% only in both S and SE (P < 0.001). VO(2)max increased 23 +/- 18% in E and 16 +/- 12% in SE (both P < 0.001). The changes in the total body fat (dual X-ray absorptiometry) did not differ between groups, but significant decreases were observed in E (-5.9%, P = 0.022) and SE (-4.8%, P = 0.005). Lean mass of the legs increased 2.2-2.9% (P = 0.004-0.010) in S, SE and E. There were no differences between the groups in the changes in blood lipids, blood pressure or serum glucose and insulin. Total cholesterol and low-density lipoprotein cholesterol decreased and high-density lipoprotein cholesterol increased in E. Both S and SE showed small decreases in serum fasting insulin. Both endurance and strength training and their combination led to expected training-specific improvements in physical fitness, without interference in fitness or muscle mass development. All training methods led to increases in lean body mass, but decreases in body fat and modest improvements in metabolic risk factors were more evident with aerobic training than strength training.

Total mortality after changes in leisure time physical activity in 50 year old men: 35 year follow-up of population based cohort

OBJECTIVE

To examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation.

DESIGN

Population based cohort study with follow-up over 35 years.

SETTING

Municipality of Uppsala, Sweden.

PARTICIPANTS

2205 men aged 50 in 1970-3 who were re-examined at ages 60, 70, 77, and 82 years.

MAIN OUTCOME MEASURE

Total (all cause) mortality.

RESULTS

The absolute mortality rate was 27.1, 23.6, and 18.4 per 1000 person years in the groups with low, medium, and high physical activity, respectively. The relative rate reduction attributable to high physical activity was 32% for low and 22% for medium physical activity. Men who increased their physical activity level between the ages of 50 and 60 continued to have a higher mortality rate during the first five years of follow-up (adjusted hazard ratio 2.64, 95% confidence interval 1.32 to 5.27, compared with unchanged high physical activity). After 10 years of follow-up their increased physical activity was associated with reduced mortality to the level of men with unchanged high physical activity (1.10, 0.87 to 1.38). The reduction in mortality associated with increased physical activity (0.51, 0.26 to 0.97, compared with unchanged low physical activity) was similar to that associated with smoking cessation (0.64, 0.53 to 0.78, compared with continued smoking).

CONCLUSIONS

Increased physical activity in middle age is eventually followed by a reduction in mortality to the same level as seen among men with constantly high physical activity. This reduction is comparable with that associated with smoking cessation.

Metabolic syndrome in people with schizophrenia: a review

Metabolic syndrome and other cardiovascular risk factors are highly prevalent in people with schizophrenia. Patients are at risk for premature mortality and overall have limited access to physical health care. In part these cardio-metabolic risk factors are attributable to unhealthy lifestyle, including poor diet and sedentary behaviour. But over recent years it has become apparent that antipsychotic agents can have a negative impact on some of the modifiable risk factors. The psychiatrist needs to be aware of the potential metabolic side effects of antipsychotic medication and to include them in the risk/benefit assessment when choosing a specific antipsychotic. He should also be responsible for the implementation of the necessary screening assessments and referral for treatment of any physical illness. Multidisciplinary assessment of psychiatric and medical conditions is needed. The somatic treatments offered to people with severe and enduring mental illness should be at par with general health care in the non-psychiatrically ill population.

Extremely short duration high intensity interval training substantially improves insulin action in young healthy males

BACKGROUND

Traditional high volume aerobic exercise training reduces cardiovascular and metabolic disease risk but involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been demonstrated to produce improvements to aerobic function, but it is unknown whether HIT has the capacity to improve insulin action and hence glycemic control.

METHODS

Sixteen young men (age: 21 +/- 2 y; BMI: 23.7 +/- 3.1 kg x m-2; VO2peak: 48 +/- 9 ml x kg-1 x min-1) performed 2 weeks of supervised HIT comprising of a total of 15 min of exercise (6 sessions; 4-6 x 30-s cycle sprints per session). Aerobic performance (250-kJ self-paced cycling time trial), and glucose, insulin and NEFA responses to a 75-g oral glucose load (oral glucose tolerance test; OGTT) were determined before and after training.

RESULTS

Following 2 weeks of HIT, the area under the plasma glucose, insulin and NEFA concentration-time curves were all reduced (12%, 37%, 26% respectively, all P < 0.001). Fasting plasma insulin and glucose concentrations remained unchanged, but there was a tendency for reduced fasting plasma NEFA concentrations post-training (pre: 350 +/- 36 v post: 290 +/- 39 micromol x l-1, P = 0.058). Insulin sensitivity, as measured by the Cederholm index, was improved by 23% (P < 0.01), while aerobic cycling performance improved by approximately 6% (P < 0.01).

CONCLUSION

The efficacy of a high intensity exercise protocol, involving only ~250 kcal of work each week, to substantially improve insulin action in young sedentary subjects is remarkable. This novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle aged sedentary populations who otherwise would not adhere to time consuming traditional aerobic exercise regimes.

Cardiorespiratory fitness and components of the metabolic syndrome in sedentary men

OBJECTIVE

To investigate the relationships between fitness and components of the metabolic syndrome in sedentary men.

SUBJECTS AND METHODS

39 subjects (34-53 years) were evaluated for fitness (VO(2max)) and anthropometric, metabolic, and skeletal muscle phenotypes. VO(2max) was assessed on a bicycle ergometer whereas other variables were obtained from an oral glucose tolerance test (OGTT), hydrostatic weighing, and a muscle biopsy.

RESULTS

Pearson and partial correlations adjusted for fat mass (FM), waist circumference (WC), muscle enzyme activities (citrate synthase (CS), cytochrome c oxidase (COX)), and capillary density were used to investigate the independent relationships be tween variables. Negative correlations between VO(2max) and WC as well as blood pressure and OGTT test were observed. When adjusted for FM, correlations remained between VO(2max) and WC (r = -0.46, p < 0.01) and systolic blood pressure (r = -0.35, p < 0.05). When adjusted for WC and CS activity, all correlations were lost except for high-sensitivity C-reactive protein (hs-CRP) (r = -0.34, p < 0.05) which remained when adjusted for CS activity. Adjustment for COX activity failed to remove correlations with hs-CRP (r = -0.36, p < 0.05), age (r = 0.34, p < 0.05), WC (r = -0.35, p < 0.05), and blood pressure. Negative correlations persisted when fitness was adjusted for the mean number of capillaries.

CONCLUSION

The effects of fitness on components of the metabolic syndrome in sedentary men are explained by abdominal obesity and muscle phenotypes.

Central adiposity and associated lifestyle factors in Cree children

Aboriginal children are prone to central adiposity (CA), a component of the metabolic syndrome. The objective of this study was to determine if lifestyle factors were associated with CA in Canadian Cree children. Children aged 9-12 years were classified as having CA if their waist circumference met or exceeded the 85th percentile of the NHANES III reference. Weight status was determined using the CDC growth reference, dietary intake using three 24 h dietary recalls, physical activity using pedometers, and fitness by completion of the 20 m shuttle run test. Of the 178 children (79% participation rate), 32.6% were normal weight, 23.6% were overweight, and 43.8% were obese. Half (52.2%) of the children had CA (97.4% of obese children, 35.7% of overweight children, and 2.2% of normal weight children). Waist circumference was negatively correlated with pedometer step counts (r = -0.187, p = 0.012) and shuttle run time (r = -0.508, p < 0.001). In children with CA, waist circumference was positively correlated with sweetened beverage intake (r = 0.250, p = 0.016). The odds ratio (adjusted for age and sex) for CA for children consuming 3 or more fruits and vegetables per day was 0.43 (95% CI 0.18 - 0.98), for meeting step recommendations for a healthy body weight was 0.45 (95% CI 0.24 - 0.84), and for relative fitness was 0.12 (95% CI 0.04 - 0.33). CA was prevalent in children who were overweight and obese. Preventive strategies might include promoting a healthy diet, physical activity, and fitness.

Capacidade aeróbia de ratos alimentados com dieta rica em frutose

INTRODUÇÃO: Evidências apontam que a ingestão exacerbada de frutose pode desencadear distúrbios característicos da síndrome metabólica. OBJETIVOS: Analisar os efeitos da ingestão de dieta rica em frutose sobre aspectos metabólicos de ratos da linhagem Wistar. Adicionalmente, verificar a capacidade aeróbia através da identificação da máxima fase estável de lactato (MFEL). MÉTODOS: Dezesseis ratos foram separados em dois grupos de oito animais: a) controle, alimentados com dieta balanceada, e b) frutose, alimentados com dieta rica em frutose. Foram analisadas a tolerância à glicose (área sob a curva de glicose durante teste de tolerância à glicose), sensibilidade à insulina (taxa de remoção da glicose sérica após sobrecarga exógena de insulina), perfil lipídico sérico e concentração de lactato sanguíneo [lac]s durante exercício na intensidade da MFEL. RESULTADOS: Teste t não pareado (p < 0,05) revelou diferença para a tolerância à glicose e triglicérides, porém não houve diferença na sensibilidade à insulina e na [lac]s. Anova one way com post hoc de Newman-Keuls (p < 0,05) revelou diferença para a cinética da glicose durante o teste de tolerância, mas não para a cinética do lactato durante exercício na MSSL. CONCLUSÃO: As Alterações fisiológicas provocadas pela dieta rica em frutose e inerentes à síndrome metabólica não prejudicam a capacidade aeróbia de ratos.

Body composition and fitness during strength and/or endurance training in older men

PURPOSE

This study examined adaptations in body composition and physical fitness during a 21-wk strength and/or endurance training period in 40- to 65-yr-old men. We also compared the usefulness of different methods for the analysis of body composition to detect training-induced adaptations.

METHODS

Fifty-three men were randomized into the endurance training (E: N = 14), strength training (S: N = 13), combined strength and endurance training (SE: N = 15), or control (C: N = 11) groups. S and E trained 2 and SE 2 x 2 times a week for strength and endurance.

RESULTS

Percentage of fat (fat%) decreased (5-8%) similarly in all training groups. Fat% measured by DXA at baseline and its change correlated with those recorded by bioimpedance (r = 0.90 and 0.66), skinfolds (r = 0.80 and 0.78), and waistline (r = 0.84 and 0.74). Lean mass in legs (DXA) increased only in S (2.0 +/- 1.5%, P < 0.001), but the thickness of vastus lateralis and intermedius measured by ultrasound increased (7-11%) in all training groups, and that of triceps brachii increased in S (22%) and SE (20%). Maximal concentric force increased significantly in S, SE, and E (by 22, 23, and 7%), and maximal oxygen uptake increased in both E (11%) and SE (11%).

CONCLUSIONS

Waist circumference and skinfold thickness seem to reasonably assess changes in percent body fat during training. However, only DXA was capable to separate small differences between the groups in training-induced changes in lean body mass. Combined strength and endurance training is of greater value than either alone in optimizing body composition or improving physical fitness in older men.

Effects of strength and endurance training on metabolic risk factors in healthy 40-65-year-old men

This study compared 21 weeks of combined high-intensity strength and endurance training with endurance or strength training only on metabolic risk factors in 40-65-year-old men. The healthy men (n=63) were randomized into endurance (E), strength (S), combined strength and endurance training (SE) and control (C) groups. S and E trained two times a week and SE 2+2 times a week. Systolic (SBP) and diastolic blood pressure decreased significantly both in E (-6+/-8 and -4+/-6 mmHg) and in S (-9+/-8 and -5+/-7 mmHg), but not in SE or C (P=0.003 for the difference in the changes of SBP between the groups). The changes in serum glucose and insulin during an oral glucose tolerance test did not differ between the groups. Only E decreased serum fasting insulin levels (-17+/-27%, P=0.013). Minor changes were observed in blood lipids and lipoproteins in all groups. Both endurance and strength training can modestly improve metabolic health even in relatively lean older men with normal glucose tolerance. Combined strength and endurance training did not produce complementary benefits on metabolic risk factors. Combined training is effective in improving body composition and cardiorespiratory and muscular fitness, however, which is likely to decrease the risk of future metabolic and cardiovascular disease.

Metabolic syndrome status changes with fitness level change: a retrospective analysis

BACKGROUND

Cardiorespiratory fitness level is inversely related to the incidence of Metabolic Syndrome (MetS). This study examined the effects of changes in cardiorespiratory fitness level on MetS status.

METHODS

Male and female participants in a health enhancement program (n = 212) were clinically examined for changes in their MetS status and estimated aerobic capacity over a 3-year period. Two physical examinations, each including a maximal treadmill stress test, occurred within this time frame. Participants were divided into three groups: Group 1 (n = 103) was composed of individuals who presented with MetS at exam 1 and reversed their MetS disease status by exam 2; Group 2 (n = 75) members presented with MetS at both exams; and Group 3 (n = 34) individuals were MetS-free at exam 1 but acquired MetS by exam 2. The relationships between MetS clinical characteristics at exam 1 and exam 2 and changes in graded exercise test (GXT) duration were contrasted for the three groups.

RESULTS

GXT duration, estimated aerobic capacity (VO(2) max), and MetS characteristics improved significantly in Group 1 (P < 0.01). Group 2 individuals also increased GXT duration (P < 0.05) but showed only nonsignificant improvements (P > 0.05) in clinical characteristics. Group 3 members declined in most MetS characteristics and in estimated VO(2) max (P < 0.05).

CONCLUSIONS

Increases in GXT duration accompanied MetS reversal while declines in GXT duration occurred with MetS acquisition. On an individual basis, these changes in GXT duration may be an indicator of disease status.

Impact of social support intensity on walking in the severely obese: a randomized clinical trial

OBJECTIVE

There are few established methods for promoting physical activity (PA) in the severely obese. Because social support is a potential method for promoting PA, we compared mean steps/day during 18 weeks in severely obese outpatients receiving either standard support (SS) or added support (AS).

METHODS AND PROCEDURES

Eighty severely obese outpatients from an obesity clinic were invited; 66 provided written consent, 55 were randomized, and 42 were included in final analyses (9 men, 33 women; age 44.4 +/- 13.1 years; BMI 41.9 +/- 5.5 kg/m(2)). All participants received a pedometer and a walking promotion booklet. In addition to SS, the AS group received ten 2-h group counseling sessions aimed at increasing weekly accumulated steps, every second week during the study. Each participant was asked to complete a 7-day walking diary every second week (10 observations).

RESULTS

Baseline steps/day was 6,912 for the AS group and 5,311 for the SS group (P = 0.023). Data at 18 weeks showed that the AS group recorded 10,136 steps/day and the SS group 6,118 steps/day (P = 0.024). There was no allocation x time interaction (P = 0.46). During the follow-up period as a whole, the AS group recorded 1,794 more steps/day than the SS group (P = 0.0074).

DISCUSSION

The AS group recorded more steps/day than the SS group, reaching a mean level of approximately 10,000 steps/day. However, the nonsignificant interaction between allocation x time suggests that this difference was present already at baseline and did not increase during follow-up.

Continuous glucose monitoring counseling improves physical activity behaviors of individuals with type 2 diabetes: A randomized clinical trial

AIMS

Despite the known benefits, 60% of individuals with diabetes do not engage in regular physical activity (PA). This pilot study tested the effects of a counseling intervention using continuous glucose monitoring system (CGMS) feedback on PA self-efficacy, PA levels, and physiological variables.

METHODS

Adults (N=52) with type 2 diabetes (non-insulin requiring, inactive) were randomized to intervention (n=27) or control (n=25) groups. Both groups received 90min of diabetes education with a follow-up phone call 4 weeks later. The intervention group also received counseling derived from self-efficacy theory. This intervention included feedback on each participant's CGMS graph and used role model CGMS graphs to clearly depict glucose reductions in response to PA. Outcomes were assessed at baseline and 8 weeks.

RESULTS

Participants receiving the intervention had higher self-efficacy scores than the control group for sticking to activity/resisting relapse at 8 weeks (p<0.05), indicating more confidence in maintaining a PA program. Intervention group participants light/sedentary activity minutes decreased significantly (p<0.05), moderate activity minutes increased significantly (p<0.05), and, HbA1c and BMI decreased significantly (p<0.05).

CONCLUSIONS

These data suggest that PA counseling interventions using CGMS feedback for individuals with type 2 diabetes may improve PA levels and reduce risk factors for diabetes-related complications.

Interaction of single nucleotide polymorphisms in ADRB2, ADRB3, TNF, IL6, IGF1R, LIPC, LEPR, and GHRL with physical activity on the risk of type 2 diabetes mellitus and changes in characteristics of the metabolic syndrome: The Finnish Diabetes Prevention Study

Single nucleotide polymorphisms (SNPs) in the ADRB2, ADRB3, TNF, IL6, IGF1R, LIPC, LEPR, and GHRL genes were associated with the conversion from impaired glucose tolerance (IGT) to type 2 diabetes mellitus (T2D) in the Finnish Diabetes Prevention Study (DPS). In this study, we determined whether polymorphisms in these genes modified the effect of changes in physical activity (PA) on the risk of T2D in the DPS. Moreover, we assessed whether the polymorphisms modified the effect of changes in PA on changes in measures of body fat, serum lipids, and blood pressure during the first year of the follow-up of the DPS. Overweight subjects with IGT (n = 487) were followed for an average of 4.1 years, and PA was assessed annually with a questionnaire. The interactions of the polymorphisms with changes in total and moderate-to-vigorous PA on the conversion to T2D during the 4.1-year follow-up were assessed using Cox regression with adjustments for the other components of the intervention (dietary changes, weight reduction). Univariate analysis of variance was used to assess interactions on changes in continuous variables during the first year of the follow-up. No interaction between the polymorphisms and PA on the conversion to T2D was found. The Leu72Met (rs696217) polymorphism in GHRL modified the effect of moderate-to-vigorous PA on changes in weight and waist circumference, the -501A/C (rs26802) polymorphism in GHRL modified the effect of total and moderate-to-vigorous PA on change in high-density lipoprotein cholesterol, and the Lys109Arg (rs1137100) polymorphism in LEPR modified the effect of total PA on change in blood pressure. In conclusion, genetic variation may modify the magnitude of the beneficial effects of PA on characteristics of the metabolic syndrome in persons with IGT.

Systemic and mitochondrial adaptive responses to moderate exercise in rodents

The systemic and nonmuscular adaptive response to moderate exercise is reviewed and compared with muscle responses to moderate and exhaustive exercise. Rats participating in voluntary wheel running and mice subjected to treadmill exercise on a lifelong basis showed 10-19% increased median life span. Mice also showed improved neurological functions, such as better (35-216%) neuromuscular coordination (tightrope test) and better (11-27%) exploratory activity (T maze). These effects are consistent with the systemic effects of moderate exercise lowering hyperglycemia, hypercholesterolemia, and hypertension. Mitochondria isolated from brain, liver, heart, and kidney of exercised mice show a 12-32% selectively increased complex IV activity, with a significant correlation between complex IV activity and performance in the tightrope test. Chronic exercise decreases (10-20%) the mitochondrial content of TBARS and protein carbonyls in the four organs after 24 weeks of training. Protein carbonyls were linearly and negatively related to complex IV activity. Exercise increased the levels of nNOSmu in human muscle and of nNOS in mouse brain. It is concluded that chronic moderate exercise exerts a whole-body beneficial effect that exceeds muscle adaptation, likely through mechanosensitive afferent nerves and beta-endorphin release to brain and plasma that promote mitochondrial biogenesis in distant organs.

Cardiorespiratory fitness and metabolic syndrome: US National Health and Nutrition Examination Survey 1999-2002

Increasing physical activity is recommended as a therapeutic lifestyle change in the treatment of metabolic syndrome (MetS); however, little evidence exists for a relationship between cardiorespiratory fitness (CRF) and MetS in representative samples. Using data from the US National Health and Nutrition Examination Survey, 1999-2002, the relationship between CRF and MetS was examined in 692 men and 608 women between the ages of 18 and 49 y who were free of major disease and disability. In men, the odds of MetS were significantly lower in moderate and high CRF categories versus the low CRF category, whereas in women there were no significant relationships between CRF and MetS.