Effects of active commuting and leisure-time exercise on fat loss in women and men with overweight and obesity: a randomized controlled trial.

BACKGROUND: Aerobic exercise is recommended for weight management but energy balance is often less negative than predicted from exercise energy expenditure (ExEE). OBJECTIVE: To examine effects of active commuting and leisure-time exercise on fat loss in women and men with overweight and obesity. METHODS: We randomized 130 younger, physically inactive women and men with overweight and obesity (body mass index: 25-35 kg m-2) to 6 months of habitual lifestyle (control; CON, n=18), active commuting (BIKE, n=35) or leisure-time exercise of moderate (MOD, 50% VO2peak reserve, n=39) or vigorous intensity (VIG, 70% VO2peak reserve, n=38). The primary outcome was change in fat mass measured by dual-energy X-ray absorptiometry, which was analyzed intention-to-treat. Accumulated energy balance was calculated based on changes in body composition, and ExEE was calculated based on heart rate monitoring during exercise. RESULTS: Testing at 3 and 6 months was completed by 95 and 90 participants, respectively. Fat mass was reduced after 3 and 6 months in BIKE (3 months: -3.6 (-5.5; -1.7) kg (mean (95% CI)); 6 months: -4.2 (-6.6; -1.9) kg; both: P<0.001), MOD (3 months: -2.2 (-3.9; -0.4) kg; 6 months: -2.6 (-4.8; -0.5) kg, both: P<0.02) and VIG (3 months: -3.4 (-5.2; -1.7) kg; 6 months: -4.5 (-6.6; -2.3) kg; both: P<0.001) compared with CON. Furthermore, fat loss was greater in VIG compared with MOD (6 months: -1.8 (-3.6; -0.1) kg, P=0.043). Based on the ExEE and the accumulated energy balance MOD compensated for the ExEE (77 (48; 106) %) but not BIKE (38 (-18; 95) %) and VIG (21 (-14; 55) %). CONCLUSIONS: A meaningful fat loss was obtained by 6 months of active commuting and leisure-time exercise, but fat loss was greater with vigorous compared with moderate intensity exercise. Active commuting is an alternative to leisure-time exercise in the management of overweight and obesity. The trial was registered at clinicaltrials.gov as NCT01962259 (main trial) and NCT01973686 (energy metabolism sub-study).

Changes in peak fat oxidation in response to different doses of endurance training.

The effect of different doses of endurance training on the capacity to oxidize fat during exercise in sedentary, overweight men and assessment of variables associated with changes in peak fat oxidation (PFO) were evaluated. Young, sedentary, overweight men were randomized to either the high-dose (HIGH, 600 kcal/day, n = 17) or moderate-dose (MOD, 300 kcal/day, n = 18) endurance training groups or controls (CON, n = 15). PFO and peak oxygen uptake (VO2 peak) were measured using indirect calorimetry, body composition using dual-energy x-ray absorptiometry, and protein levels of mitochondrial enzymes determined by Western blotting. PFO increased in both MOD [1.2 mg/kg fat-free mass (FFM)/min, 95% confidence interval (CI): 0.08:2.3, P = 0.03] and HIGH (1.8 mg/kg FFM/min, CI: 0.6:2.9, P < 0.001) compared with CON. Skeletal muscle expression of citrate synthase, ß-hydroxyacyl-CoA dehydrogenase, and mitochondrial oxphos complexes II-V increased similarly in MOD and HIGH. Stepwise multiple linear regression analysis with backward elimination of individual variables correlated with changes in PFO revealed increases in cycling efficiency, FFM, and VO2 peak as the remaining associated variables. In conclusion, PFO during exercise increased with both moderate- and high-dose endurance training. Increases in PFO were mainly predicted by changes in VO2 peak, FFM, and cycling efficiency, and less with skeletal muscle mitochondrial enzymes.

Exercise training favors increased insulin-stimulated glucose uptake in skeletal muscle in contrast to adipose tissue: a randomized study using FDG PET imaging.

Physical exercise increases peripheral insulin sensitivity, but regional differences are poorly elucidated in humans. We investigated the effect of aerobic exercise training on insulin-stimulated glucose uptake in five individual femoral muscle groups and four different adipose tissue regions, using dynamic (femoral region) and static (abdominal region) 2-deoxy-2-[¹8F]fluoro-d-glucose (FDG) PET/CT methodology during steady-state insulin infusion (40 mU·m⁻²·min⁻¹). Body composition was measured by dual X-ray absorptiometry and MRI. Sixty-one healthy, sedentary [V(O2max) 36(5) ml·kg⁻¹·min⁻¹; mean(SD)], moderately overweight [BMI 28.1(1.8) kg/m²], young [age: 30(6) yr] men were randomized to sedentary living (CON; n = 17 completers) or moderate (MOD; 300 kcal/day, n = 18) or high (HIGH; 600 kcal/day, n = 18) dose physical exercise for 11 wk. At baseline, insulin-stimulated glucose uptake was highest in femoral skeletal muscle followed by intraperitoneal visceral adipose tissue (VAT), retroperitoneal VAT, abdominal (anterior + posterior) subcutaneous adipose tissue (SAT), and femoral SAT (P < 0.0001 between tissues). Metabolic rate of glucose increased similarly (~30%) in the two exercise groups in femoral skeletal muscle (MOD 24[9, 39] µmol·kg⁻¹·min⁻¹, P = 0.004; HIGH 22[9, 35] µmol·kg⁻¹·min⁻¹, P = 0.003) (mean[95% CI]) and in five individual femoral muscle groups but not in femoral SAT. Standardized uptake value of FDG decreased ~24% in anterior abdominal SAT and ~20% in posterior abdominal SAT compared with CON but not in either intra- or retroperitoneal VAT. Total adipose tissue mass decreased in both exercise groups, and the decrease was distributed equally among subcutaneous and intra-abdominal depots. In conclusion, aerobic exercise training increases insulin-stimulated glucose uptake in skeletal muscle but not in adipose tissue, which demonstrates some interregional differences.

Maintenance of cardiorespiratory fitness, body composition, and a physically active lifestyle after structured exercise interventions in individuals with overweight and obesity: A mixed-method follow-up study.

Objectives: The aim of this mixed-method study was to explore maintenance of physical activity and health effects one year after completion of exercise interventions in transport and leisure-time domains of everyday life. We hypothesised that routinisation of active commuting would lead to better maintenance of physical activity and health effects compared with leisure-time exercise. Study design: Mixed-methods follow-up study. Methods: Individuals with overweight/obesity, who completed a 6-month exercise intervention (active commuting by bike (BIKE), moderate (MOD) or vigorous intensity leisure-time exercise (VIG)), were after one year invited to participate in a follow-up visit which included measurements of cardiorespiratory fitness during an incremental bicycle test and body composition using dual-energy X-ray absorptiometry. Variability in maintenance practices was assessed in a sub-sample of participants who experienced the greatest improvements ('VO2peak improvers') and reductions ('VO2peak reducers'), respectively, in cardiorespiratory fitness. Semi-structured interviews were conducted (15-30 min) and analysed using systematic text condensation to identify barriers and facilitators associated with maintenance of physical activity. Results: Out of the 74 participants completing an exercise intervention, 46 (62%) completed follow-up (BIKE: n = 14; MOD: n = 14; VIG: n = 18). Improvements in VO2peak and reductions in fat mass were maintained in BIKE and VIG. Body weight decreased in BIKE and fat free mass increased in VIG. Changes in VO2peak and anthropometry at follow-up did not differ between BIKE and MOD + VIG. Fat mass decreased and recreational physical activity increased in 'VO2peak improvers'. Findings from the interviews suggested that self-monitoring, collective exercising, and new personal exercise challenges facilitate maintenance of a physically active lifestyle. Conclusion: Completion of a structured exercise intervention consisting of 6 months of active commuting or vigorous intensity leisure-time exercise was associated with long-term maintenance of improvements in VO2peak and body composition, whereas moderate intensity leisure-time exercise was not. In contrast to our hypothesis, active commuting was not associated with better maintenance of physical activity and health effects after the intervention compared with leisure-time exercise.

Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans.

AIM/HYPOTHESIS: The aim of this study was to investigate mitochondrial function, fibre-type distribution and substrate oxidation during exercise in arm and leg muscles in male postobese (PO), obese (O) and age- and body mass index (BMI)-matched control (C) subjects. The hypothesis of the study was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss. METHODS: Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry. RESULTS: During the graded exercise tests, peak fat oxidation during leg cycling and the relative workload at which it occurred (FatMax) were higher in PO and O than in C. During arm cranking, peak fat oxidation was higher in O than in C, and FatMax was higher in O than in PO and C. Similar fibre-type composition was found between groups. Plasma adiponectin was higher in PO than in C and O, and plasma leptin was higher in O than in PO and C. CONCLUSIONS: In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations, but not with differences in fibre-type composition, mitochondrial function or muscle enzyme levels compared with Cs. In PO subjects, the changes in fat oxidation are preserved during leg, but not during arm, exercise.

Insulin resistance induced by physical inactivity is associated with multiple transcriptional changes in skeletal muscle in young men.

Physical inactivity is a risk factor for insulin resistance. We examined the effect of 9 days of bed rest on basal and insulin-stimulated expression of genes potentially involved in insulin action by applying hypothesis-generating microarray in parallel with candidate gene real-time PCR approaches in 20 healthy young men. Furthermore, we investigated whether bed rest affected DNA methylation in the promoter region of the peroxisome proliferator-activated receptor-γ coactivator-1α (PPARGC1A) gene. Subjects were reexamined after 4 wk of retraining. We found that bed rest induced insulin resistance and altered the expression of more than 4,500 genes. These changes were only partly normalized after 4 wk of retraining. Pathway analyses revealed significant downregulation of 34 pathways, predominantly those of genes associated with mitochondrial function, including PPARGC1A. Despite induction of insulin resistance, bed rest resulted in a paradoxically increased response to acute insulin stimulation in the general expression of genes, particularly those involved in inflammation and endoplasmatic reticulum (ER) stress. Furthermore, bed rest changed gene expressions of several insulin resistance and diabetes candidate genes. We also observed a trend toward increased PPARGC1A DNA methylation after bed rest. We conclude that impaired expression of PPARGC1A and other genes involved in mitochondrial function as well as a paradoxically increased response to insulin of genes involved in inflammation and ER stress may contribute to the development of insulin resistance induced by bed rest. Lack of complete normalization of changes after 4 wk of retraining underscores the importance of maintaining a minimum of daily physical activity.

Increased rate of whole body lipolysis before and after 9 days of bed rest in healthy young men born with low birth weight.

Individuals born with low birth weight (LBW) are at risk of developing type 2 diabetes mellitus (T2D), which may be precipitated by physical inactivity. Twenty-two LBW subjects and twenty-three controls were studied before and after bed rest by the hyperinsulinemic euglycemic clamp combined with indirect calorimetry and infusion of stable isotope tracers and preceded by an intravenous glucose tolerance test. LBW subjects had a similar body mass index but elevated abdominal obesity compared with controls. The basal rate of whole body lipolysis (WBL) was elevated in LBW subjects with and without correction for abdominal obesity before and after bed rest (all P = 0.01). Skeletal muscle hormone-sensitive lipase (HSL) protein expression and phosphorylation at Ser565 were similar in the two groups. Bed rest resulted in a decrease in WBL and an increased skeletal muscle HSL Ser565 phosphorylation indicating a decreased HSL activity in both groups. All subjects developed peripheral insulin resistance in response to bed rest (all P < 0.0001) with no differences between groups. LBW subjects developed hepatic insulin resistance in response to bed rest. In conclusion, increased WBL may contribute to the development of hepatic insulin resistance when exposed to bed rest in LBW subjects. Nine days of bed rest causes severe peripheral insulin resistance and reduced WBL and skeletal muscle HSL activity, as well as a compensatory increased insulin secretion, with no differences in LBW subjects and controls.

Fat oxidation at rest predicts peak fat oxidation during exercise and metabolic phenotype in overweight men.

OBJECTIVE: To elucidate if fat oxidation at rest predicts peak fat oxidation during exercise and/or metabolic phenotype in moderately overweight, sedentary men. DESIGN: Cross-sectional study. SUBJECTS: We measured respiratory exchange ratio (RER) at rest in 44 moderately overweight, normotensive and normoglycemic men and selected 8 subjects with a low RER (L-RER, body mass index (BMI): 27.9+/-0.9 kg m(-2), RER: 0.76+/-0.02) and 8 with a high RER (H-RER; BMI 28.1+/-1.1 kg m(-2), RER: 0.89+/-0.02). After an overnight fast, a venous blood sample was obtained and a graded exercise test was performed. Fat oxidation during exercise was quantified using indirect calorimetry. RESULTS: Peak fat oxidation during exercise was higher in L-RER than in H-RER (0.333+/-0.096 vs 0.169+/-0.028 g min(-1); P<0.01) and occurred at a higher relative intensity (36.2+/-6.6 vs 28.2+/-3.1% VO(2max), P<0.05). Using the International Diabetes Federation criteria, we found that there was a lower accumulation of metabolic risk factors in L-RER than in H-RER (1.6 vs 3.5, P=0.028), and no subjects in L-RER and four of eight subjects in H-RER had the metabolic syndrome. Resting RER was positively correlated with plasma triglycerides (P<0.01) and negatively with plasma free fatty acids (P<0.05), and peak fat oxidation during exercise was positively correlated with plasma free fatty acid concentration at rest (P<0.05). CONCLUSION: A low RER at rest predicts a high peak fat oxidation during exercise and a healthy metabolic phenotype in moderately overweight, sedentary men.

Diminished insulin-mediated forearm blood flow and muscle glucose uptake in young men with low birth weight.

BACKGROUND: Low birth weight (LBW) is associated with increased risk of type 2 diabetes and cardiovascular disease. We studied endothelial function and insulin sensitivity in young men with LBW (n = 22) and controls (n = 22). METHODS: Insulin sensitivity and endothelial function was studied with venous occlusion plethysmography and intra-arterial infusions of adenosine and acetylcholine, before and during a hyperinsulinemic isoglycemic clamp. RESULTS: Forearm blood flow response to systemic hyperinsulinemia was diminished in LBW compared to controls (p < 0.05). Fractional arteriovenous glucose extraction was similar, and consequently insulin-stimulated forearm glucose clearance was diminished in LBW compared with controls (0.8 +/- 0.09 vs. 1.4 +/- 0.36 ml x 100 ml(-1) x min(-1), respectively, p < 0.05). Forearm blood flow response to adenosine and acetylcholine with or without insulin stimulation did not differ between groups. Whole-body glucose uptake was lower in LBW than controls (8.7 +/- 0.5 and 9.1 +/- 0.6 mg x min(-1) x kg(-1) lean body mass); however, this was not significant. CONCLUSIONS: Forearm blood flow response to insulin is impaired in LBW, whereas the response to adenosine and acetylcholine is preserved. The impaired insulin-mediated increase in bulk flow in LBW may be due to an impairment of insulin-mediated capillary recruitment independent of - or preceding - whole-body insulin resistance in LBW subjects.

Leptin receptor 170 kDa (OB-R170) protein expression is reduced in obese human skeletal muscle: a potential mechanism of leptin resistance.

To examine whether obesity-associated leptin resistance could be due to down-regulation of leptin receptors (OB-Rs) and/or up-regulation of suppressor of cytokine signalling 3 (SOCS3) and protein tyrosine phosphatase 1B (PTP1B) in skeletal muscle, which blunt janus kinase 2-dependent leptin signalling and signal transducer and activator of transcription 3 (STAT3) phosphorylation and reduce AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase (ACC) phosphorylation. Deltoid and vastus lateralis muscle biopsies were obtained from 20 men: 10 non-obese control subjects (mean +/- s.d. age, 31 +/- 5 years; height, 184 +/- 9 cm; weight, 91 +/- 13 kg; and percentage body fat, 24.8 +/- 5.8%) and 10 obese (age, 30 +/- 7 years; height, 184 +/- 8 cm; weight, 115 +/- 8 kg; and percentage body fat, 34.9 +/- 5.1%). Skeletal muscle OB-R170 (OB-R long isoform) protein expression was 28 and 25% lower (both P < 0.05) in arm and leg muscles, respectively, of obese men compared with control subjects. In normal-weight subjects, SOCS3 protein expression, and STAT3, AMPKalpha and ACCbeta phosphorylation, were similar in the deltoid and vastus lateralis muscles. In obese subjects, the deltoid muscle had a greater amount of leptin receptors than the vastus lateralis, whilst SOCS3 protein expression was increased and basal STAT3, AMPKalpha and ACCbeta phosphorylation levels were reduced in the vastus lateralis compared with the deltoid muscle (all P < 0.05). In summary, skeletal muscle leptin receptors and leptin signalling are reduced in obesity, particularly in the leg muscles.

Cerebral oxygenation and metabolism during exercise following three months of endurance training in healthy overweight males.

Endurance training improves muscular and cardiovascular fitness, but the effect on cerebral oxygenation and metabolism remains unknown. We hypothesized that 3 mo of endurance training would reduce cerebral carbohydrate uptake with maintained cerebral oxygenation during submaximal exercise. Healthy overweight males were included in a randomized, controlled study (training: n = 10; control: n = 7). Arterial and internal jugular venous catheterization was used to determine concentration differences for oxygen, glucose, and lactate across the brain and the oxygen-carbohydrate index [molar uptake of oxygen/(glucose + (1/2) lactate); OCI], changes in mitochondrial oxygen tension (DeltaP(Mito)O(2)) and the cerebral metabolic rate of oxygen (CMRO(2)) were calculated. For all subjects, resting OCI was higher at the 3-mo follow-up (6.3 +/- 1.3 compared with 4.7 +/- 0.9 at baseline, mean +/- SD; P < 0.05) and coincided with a lower plasma epinephrine concentration (P < 0.05). Cerebral adaptations to endurance training manifested when exercising at 70% of maximal oxygen uptake (approximately 211 W). Before training, both OCI (3.9 +/- 0.9) and DeltaP(Mito)O(2) (-22 mmHg) decreased (P < 0.05), whereas CMRO(2) increased by 79 +/- 53 micromol x 100 x g(-1) min(-1) (P < 0.05). At the 3-mo follow-up, OCI (4.9 +/- 1.0) and DeltaP(Mito)O(2) (-7 +/- 13 mmHg) did not decrease significantly from rest and when compared with values before training (P < 0.05), CMRO(2) did not increase. This study demonstrates that endurance training attenuates the cerebral metabolic response to submaximal exercise, as reflected in a lower carbohydrate uptake and maintained cerebral oxygenation.

Immunometabolic parameters in overweight dogs during weight loss with or without an exercise program.

The influence of physical activity on metabolic health in overweight dogs is unknown. This study was conducted to evaluate biomarkers of immunometabolic health in relation to changes in physical activity and adiposity. Client-owned overweight dogs participated in a 12-wk intervention based on caloric restriction combined with a training program (fitness and diet [FD] group, n = 8), or caloric restriction alone (diet-only [DO] group, n = 8). Physical activity was monitored by accelerometry. All dogs were fed the same diet and achieved similar weight loss. Fasting blood samples were collected before and after 6- and 12-wk intervention. Insulin resistance was evaluated from plasma insulin and C-peptide as well as homeostasis model assessment. Inflammation and dyslipidemia were evaluated from circulating leptin, adiponectin, C-reactive protein (CRP), monocyte chemoattractant factor-1 (MCP-1), interleukin-8 (IL-8), and cholesterol. Accelerometer counts in both groups were high compared with previous reports of physical activity in overweight dogs. No difference in blood parameters was evident between groups, evaluated by linear mixed-effects model (P > 0.05). Within the groups, the following changes were significant by t-test (P < 0.05): leptin decreased in both groups. Within the FD group, IL-8, MCP-1, and CRP decreased at 6 wk and IL-8 and cholesterol at 12 wk. Within the DO group, C-peptide and HOMA decreased at 6 wk and C-peptide at 12 wk. We conclude that, for both groups, weight loss resulted in minor indications of improved immunometabolic health, whereas this level of physical activity did not add further benefits.

Maintenance of improvements in fitness and fatness 1 year after a 3-month lifestyle intervention in overweight men.

Sustained improvements in cardiovascular fitness and body composition after lifestyle interventions are challenging. The present study investigated whether changes in cardiovascular fitness and body composition were maintained for up to 1 year after similar exercise-induced (T) or diet-induced weight loss (D) or exercise without weight loss (T-iD) in overweight sedentary men. Six and 12 months after the interventions, we measured cardiovascular fitness and body composition. Cardiovascular fitness was higher at both 6- (3.2±1.5 ml O2/kg/min, P=0.053) and 12-month follow-up (3.9±1.4 ml O2/kg/min, P=0.049) compared with pre-intervention in T. Fat mass (-3.0±1.2 kg, P=0.04) and abdominal fat (-3.6±1.5%, P=0.04) were lower within T at 12-month follow-up compared with pre-intervention. This did not occur in D (P>0.13) or T-iD (P>0.14), although body weight was lower in D (-2.5±2.2 kg, P=0.09). This study showed that fitness and fatness were not returned to pre-intervention levels 1 year after a 3-month exercise-induced weight-loss intervention.

Estimation of rat muscle blood flow by microdialysis probes perfused with ethanol, [14C]ethanol, and 3H2O.

We used the perfused rat hindquarter to evaluate whether the microdialysis ethanol technique can be used to qualitatively estimate nutritive skeletal muscle blood flow. Four microdialysis probes were inserted in different hindlimb muscles in each of 16 rats. Hindquarters were perfused at blood flow rates ranging from 0 to 21 ml. 100 g-1. min-1. The microdialysis probes were perfused at 2 microliter/min with perfusate containing ethanol, [14C]ethanol, and 3H2O. Within and between experiments outflow-to-inflow ratios (o/i) generally varied inversely with blood flow. When a low flow or no flow was maintained in hindquarters, o/i ratios first increased with time (for at least 60 min) and then leveled off. The long time constant impaired detection of rapid oscillations in blood flow, especially at low blood flow rates. Contractions per se apparently decreased o/i ratios independent of blood flow. Ethanol and [14C]ethanol o/i ratios did not differ. 3H2O o/i paralleled ethanol and [14C]ethanol o/i ratios but it was significantly lower. In conclusion, differences in skeletal muscle blood flow can be detected by the microdialysis technique. However, the slow changes in o/i, in particular at low blood flow rates, limit the usefulness of the technique for measuring dynamic changes in blood flow; caution must also be exerted during muscle contractions. 3H2O and [14C]ethanol are good alternatives to ethanol in the determination of blood flow by microdialysis.

Hormone-sensitive lipase (HSL) expression and regulation in skeletal muscle.

Because the enzymatic regulation of muscle triglyceride metabolism is poorly understood we explored the character and activation of neutral lipase in muscle. Western blotting of isolated rat muscle fibers demonstrated expression of hormone-sensitive lipase (HSL). In incubated soleus muscle epinephrine increased neutral lipase activity by beta-adrenergic mechanisms involving cyclic AMP-dependent protein kinase (PKA). The increase was paralleled by an increase in glycogen phosphorylase activity and could be abolished by antiserum against HSL. Electrical stimulation caused a transient increase in activity of both neutral lipase and glycogen phosphorylase. The increase in lipase activity during contractions was not influenced by sympathectomy or propranolol. Training diminished the epinephrine induced lipase activation in muscle but enhanced the activation as well as the overall concentration of lipase in adipose tissue. In agreement with the in vitro findings, in adrenalectomized patients an increase in muscle neutral lipase activity was found at the end of prolonged exercise only if epinephrine was infused. In accordance with feedforward regulation of substrate mobilization in exercise, our studies have shown that HSL is present in skeletal muscle cells and is stimulated in parallel with glycogen phosphorylase by both epinephrine and contractions. HSL adapts differently to training in muscle compared with adipose tissue.

[Alternative treatment of athletic injuries]. / Alternativ behandling af idraetsskader.

A questionnaire was carried out in a Danish sports clinic to find out how many sports-injured patients seek alternative medical treatment. One hundred and fifty persons (81%) answered the questionnaire. Forty-seven percent of the women and 35% of the men had at some time tried alternative medicine. These high numbers might be explained by dissatisfaction with the official medical treatment of sports injuries in Denmark. No age or income difference was found between the persons who had tried alternative medicine compared to the patients who had never tried it. Fifty-nine percent of those who had sought alternative medicine did not find it effective. There is a need for clinically controlled trials to find out if some alternative medical treatments do have effects on some specified injuries.

Only minor additional metabolic health benefits of high as opposed to moderate dose physical exercise in young, moderately overweight men.

OBJECTIVE: The dose-response effects of exercise training on insulin sensitivity, metabolic risk, and quality of life were examined. METHODS: Sixty-one healthy, sedentary (VO2max: 35 ± 5 ml/kg/min), moderately overweight (BMI: 27.9 ± 1.8), young (age: 29 ± 6 years) men were randomized to sedentary living (sedentary control group; n = 18), moderate (moderate dose training group [MOD]: 300 kcal/day, n = 21), or high (high dose training group [HIGH]: 600 kcal/day, n = 22) dose physical exercise for 11 weeks. RESULTS: The return rate for post-intervention testing was 82-94% across groups. Weekly exercise amounted to 2,004 ± 24 and 3,774 ± 68 kcal, respectively, in MOD and HIGH. Cardiorespiratory fitness increased (P < 0.001) 18 ± 3% in MOD and 17 ± 3% in HIGH, and fat percentage decreased (P < 0.001) similarly in both exercise groups (MOD: 32 ± 1 to 29 ± 1%; HIGH: 30 ± 1 to 27 ± 1%). Peripheral insulin sensitivity increased (P < 0.01) (MOD: 28 ± 7%; HIGH: 36 ± 8%) and the homeostasis model assessment of insulin resistance decreased (P < 0.05) (MOD: -17 ± 7%; HIGH: -18 ± 10%). The number of subjects meeting the criteria of the metabolic syndrome decreased by 78% in MOD (P < 0.01) and by 80% in HIGH (P < 0.05). General health assessed by questionnaire increased similarly in MOD (P < 0.05) and HIGH (P < 0.01). CONCLUSIONS: Only minor additional health benefits were found when exercising ∼3,800 as opposed to ∼2,000 kcal/week in young moderately overweight men. This finding may have important public health implications.

Improved glucose tolerance after intensive life style intervention occurs without changes in muscle ceramide or triacylglycerol in morbidly obese subjects.

AIM: This study investigated the effect of a 15-week life style intervention (hypocaloric diet and regular exercise) on glucose tolerance, skeletal muscle lipids and muscle metabolic adaptations in 14 female and 9 male morbidly obese subjects (age: 32.5±2.3 years, body mass index: 46.1±1.9 kg m(-2) ). METHOD: Before and after the life style intervention, an oral glucose tolerance test was performed and a muscle biopsy was obtained in the fasted state. Maximal oxygen uptake was measured by an indirect test. RESULTS: After the intervention, body weight was decreased (P<0.05) by 11±1%, maximal oxygen uptake increased (P<0.05) by 18±5% and glucose tolerance increased (P<0.05) by 12±3%. Muscle glycogen was significantly increased by 47±14%, but muscle ceramide and triacylglycerol content remained completely unchanged. No sex difference was observed for any of these parameters, but during submaximal exercise a marked decrease (P<0.05) of 15±2% in respiratory exchange ratio was seen only in females indicating an enhanced fat oxidation. CONCLUSION: Despite a marked weight loss and an improved aerobic capacity muscle ceramide and triacylglycerol remained unchanged after intensive life style intervention, and muscle lipids hence do not seem to play a major role for the improved glucose tolerance in these morbidly obese subjects. Interestingly, only the females improved fat oxidation during submaximal exercise after the intervention implying the presence of a sex-dependent response to intensive life style adaptation.

No role of interstitial adenosine in insulin-mediated vasodilation.

UNLABELLED: The mechanisms behind the vasodilatory effect of insulin are not fully understood, but nitric oxide plays an important role. We have investigated the possibility that insulin mediates vasodilatation in the human skeletal muscle via an increase in extracellular adenosine concentrations. In eight healthy subjects (H) and in four subjects with a complete, high (C5-C6/7) spinal cord injury (SCI) a hyperinsulinaemic (480 mU min-1 kg-1), isoglycaemic clamp was performed. SCI subjects were included as it has been proposed that adenosine and adenine nucleotides may be released from nerve endings in the skeletal muscle. Adenosine concentrations in the extracellular fluid (ECF) of skeletal muscle in the thigh were measured by means of the microdialysis technique. Leg blood flow (LBF) was measured by termodilution. In response to insulin infusion, LBF always increased (P < 0.05) (from 228 +/- 25 and 318 +/- 18 mL min-1 to 451 +/- 41 and 530 +/- 29 mL min-1, SCI and H, respectively [mean +/- SEM]). Concentrations of adenosine in the muscle ECF did not change with infusion of insulin and did not differ between groups (before: 147 +/- 55 [SCI] and 207 +/- 108 [H] nmol L-1; during: 160 +/- 36 [SCI] and 165 +/- 74 [H] nmol L-1). No significant correlation between concentrations of adenosine and corresponding LBF rates was achieved (LBF=[-0.0936. Adenosine] + 475. R=-0.092, P=0.22, number of samples=181, number of subjects=12). CONCLUSION: the mechanism by which insulin mediates an increase in skeletal muscle blood flow is not associated with adenosine in the ECF.