Whole-body repeated hyperthermia increases irisin and brain-derived neurotrophic factor: A randomized controlled trial.

CONTEXT: Hyperthermia is known to be beneficial to patients affected by various diseases. Irisin is a key regulators of fat metabolism known to be released as response to cold. Brain Derived Neurotrophic Factor (BDNF) is a marker of neuroplasticity usually increased as response to acute exposure to human body stressors. OBJECTIVE: Effect of a repeated hyperthermia exposure programme on changes in circulating irisin and serum BDNF in healthy humans. DESIGN: Setting, Participants: Randomized, single-blind, cross-over trial in healthy humans conducted at Sechenov University Physiology Laboratory from April 2019. The treatment period was 2 weeks (wash-out 3 weeks). Researchers analysing serum biomarkers and questionnaires data were blinded to participants allocation. Participants were 20 healthy male (age 21.5 ± 2.1 years). INTERVENTION: Hyperthermia exposure programme (WBPH) versus sham exposure (SHAM) to hyperthermia (10 sessions in two weeks). MAIN OUTCOME MEASURE: Changes in irisin and BDNF before and after short hyperthermia exposure. RESULTS: Twenty participants were analyzed. Irisin increased significantly in group WBPH only: 6.3 µg/ml (mean with SD = 1.6) compared to 5.4 µg/ml (SD = 1.7) in SHAM group; This value was also higher than baseline (5.0 mean with SD = 1.1) in WBPH. After 10 sessions mean change in BDNF was higher in WBPH group vs SHAM: BDNF was 28,263 (SD = 4213) pg/ml in WBPH group and 24,064 (SD = 5600) pg/ml in SHAM group. BDNF concentrations were significantly higher than baseline values in WBPH group only, 28,263 (SD 4213) vs 25,888 (SD 4316) pg/ml. CONCLUSION: In healthy young humans a 2-week, ten sessions programme consisting of repeated exposure to hyperthermia resulted in a significantly higher increase of circulating Irisin and BDNF.

Safety and Efficacy of Intermittent Hypoxia Conditioning as a New Rehabilitation/ Secondary Prevention Strategy for Patients with Cardiovascular Diseases: A Systematic Review and Meta-analysis.

BACKGROUND: Once used by mountaineers to facilitate rapid adaptations to altitude and by athletes to improve their aerobic capacity, exposure to hypoxia has been proven to affect various physiological, clinically relevant parameters. A form of conditioning known as Intermittent Hypoxia Conditioning (IHC) consists of repeated exposures to intermittent hypoxia, combined with normoxia and hyperoxia, which has been shown to have potential as a treatment to improve cardio- metabolic risks profile in cardiac patients but results across studies are inconsistent. This systematic review and meta-analysis aimed to evaluate the clinical effectiveness of IHC. METHODS: Four electronic databases (PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials) were searched (from inception to December 2019) to retrieve all studies focused on IHC in elderly patients with cardiovascular disease. A meta-analysis of functional, efficacy and safety outcomes in cardiac patients was completed to compare IHC to sham treatments. RESULTS: Fourteen studies with 320 patients in the Interval Hypoxia-normoxia Group (IHNG) or Interval Hypoxia-hyperoxia training Group (IHHG) and 111 patients in the control group were included in our meta-analysis. IHNT and IHHT were associated with significant reduction in heart rate, SBP, and DBP at rest after treatment [MD= -5.35 beat/min, 95% CI (-9.19 to -1.50), p=0.006], [MD= -13.72 mmHg, 95% CI (-18.31 to -9.132), p<0.001], and [MD= -7.882 mmHg, 95% CI (-13.163 to -2.601), p=0.003], respectively. There were no significant complications or serious adverse events related to IHNT/IHHT. CONCLUSION: The current evidence suggested that the use of the IHNT/IHHT program in elderly patients with CVDs can be safe and effective in terms of heart rate and elevated blood pressure. However, currently, there is no supporting evidence that IHNT/IHHT can significantly improve hematological parameters or lipid profile. Exercise tolerance increased at the end of the course of hypoxic conditioning within IHC group, but did not differ from controls. Further research is needed.

Does supplementation with leucine-enriched protein alone and in combination with fish-oil-derived n-3 PUFA affect muscle mass, strength, physical performance, and muscle protein synthesis in well-nourished older adults? A randomized, double-blind, placebo-controlled trial.

BACKGROUND: Leucine-enriched protein (LEU-PRO) and long-chain (LC) n-3 (ω-3) PUFAs have each been proposed to improve muscle mass and function in older adults, whereas their combination may be more effective than either alone. OBJECTIVE: The impact of LEU-PRO supplementation alone and combined with LC n-3 PUFAs on appendicular lean mass, strength, physical performance and myofibrillar protein synthesis (MyoPS) was investigated in older adults at risk of sarcopenia. METHODS: This 24-wk, 3-arm parallel, randomized, double-blind, placebo-controlled trial was conducted in 107 men and women aged ≥65 y with low muscle mass and/or strength. Twice daily, participants consumed a supplement containing either LEU-PRO (3 g leucine, 10 g protein; n = 38), LEU-PRO plus LC n-3 PUFAs (0.8 g EPA, 1.1 g DHA; LEU-PRO+n-3; n = 38), or an isoenergetic control (CON; n = 31). Appendicular lean mass, handgrip strength, leg strength, physical performance, and circulating metabolic and renal function markers were measured pre-, mid-, and postintervention. Integrated rates of MyoPS were assessed in a subcohort (n = 28). RESULTS: Neither LEU-PRO nor LEU-PRO+n-3 supplementation affected appendicular lean mass, handgrip strength, knee extension strength, physical performance or MyoPS. However, isometric knee flexion peak torque (treatment effect: -7.1 Nm; 95% CI: -12.5, -1.8 Nm; P < 0.01) was lower postsupplementation in LEU-PRO+n-3 compared with CON. Serum triacylglycerol and total adiponectin concentrations were lower, and HOMA-IR was higher, in LEU-PRO+n-3 compared with CON postsupplementation (all P < 0.05). Estimated glomerular filtration rate was higher and cystatin c was lower in LEU-PRO and LEU-PRO+n-3 postsupplementation compared with CON (all P < 0.05). CONCLUSIONS: Contrary to our hypothesis, we did not observe a beneficial effect of LEU-PRO supplementation alone or combined with LC n-3 PUFA supplementation on appendicular lean mass, strength, physical performance or MyoPS in older adults at risk of sarcopenia. This trial was registered at clinicaltrials.gov as NCT03429491.

A qualitative exploration of cardiovascular disease patients' views and experiences with an eHealth cardiac rehabilitation intervention: The PATHway Project.

The aim of this study is to explore participants' views and experiences of an eHealth phase 3 cardiac rehabilitation (CR) intervention: Physical Activity Towards Health (PATHway). Sixty participants took part in the PATHway intervention. Debriefs were conducted after the six-month intervention. All interviews were audio recorded and transcribed verbatim. Transcripts were analysed with Braun and Clarke's thematic analysis. Forty-four (71%) debriefs were conducted (n = 34 male, mean (SD) age 61 (10) years). Five key themes were identified: (1) Feedback on the components of the PATHway system, (2) Motivation, (3) Barriers to using PATHway, (4) Enablers to using PATHway, and (5) Post programme reflection. There were a number of subthemes within each theme, for example motivation explores participants motivation to take part in PATHway and participants motivation to sustain engagement with PATHway throughout the intervention period. Participant engagement with the components of the PATHway system was variable. Future research should focus on optimising participant familiarisation with eHealth systems and employ an iterative approach to development and evaluation.

Repeated hyperthermia exposure increases circulating Brain Derived Neurotrophic Factor levels which is associated with improved quality of life, and reduced anxiety: A randomized controlled trial.

CONTEXT: Hyperthermia is known to be beneficial to patients affected by various diseases. Brain Derived Neurotrophic Factor (BDNF) is a marker of neuroplasticity usually increased as response to acute exposure to human body stressors. Little is known about BDNF changes after repeated exposure to hyperthermia. OBJECTIVE: To investigate the effect of a repeated hyperthermia exposure programme (HTC) on serum BDNF in healthy humans. DESIGN, SETTING, PARTICIPANTS: Randomized, single-blind, controlled trial in healthy humans conducted at Sechenov University Physiology Laboratory between December 2016 and November 2018. The treatment period was 10 weeks. Researchers analysing serum BDNF and questionnaires data were blinded to participants allocation. PARTICIPANTS: Were 34 healthy male (age 20.2 ± 1.6 years). INTERVENTION: Repeated Hyperthermia exposure programme, HTC, versus Light Intermittent Exercise, LIE, programme as control (10 weeks). MAIN OUTCOME MEASURE: Change in BDNF from baseline to final visit three days after treatment completion. RESULTS: 25 participants were analyzed. One participant withdrew before signing the informed consent and 8 participants (n = 3 in HTC and n = 5 in LIE) could not undertake the first assessment and were excluded. Mean change in BDNF was higher in HTC group vs LIE after both time points (after 12 and after 24 sessions). After 24 sessions BDNF was 30170 (SD 5268) pg/ml in HTC group a value that was significantly higher than 24104 (SD 2876) pg/ml measured in LIE group. BDNF concentrations were significantly higher than baseline values in HTC group only, 30170 (SD 5268) vs 26710 (SD 5437) pg/ml. CONCLUSION: A 10-week programme consisting of repeated exposure to hyperthermia resulted in a significantly higher increase of circulating BDNF compared to a programme consisting of intermittent light intensity exercise.

High-intensity interval training accelerates oxygen uptake kinetics and improves exercise tolerance for individuals with cystic fibrosis.

BACKGROUND: Exercise training provides benefits for individuals with cystic fibrosis; however, the optimal program is unclear. High-intensity interval training is safe and effective for improving 'functional capacity' in these individuals with peak rate of O2 uptake typically referenced. The ability to adjust submaximal rate of oxygen uptake (V̇O2 kinetics) might be more important for everyday function because maximal efforts are usually not undertaken. Moreover, the ability of high-intensity training to accelerate V̇O2 kinetics for individuals with cystic fibrosis could be enhanced with O2 supplementation during training. METHODS: Nine individuals with cystic fibrosis completed incremental cycling to limit of tolerance followed by 8 weeks of high-intensity interval cycling (2 sessions per week x ~ 45 min per session) either with (n = 5; O2+) or without (AMB) oxygen supplementation (100%). Each session involved work intervals at 70% of peak work rate followed by 60 s of recovery at 35%. For progression, duration of work intervals was increased according to participant tolerance. RESULTS: Both groups experienced a significant increase in work-interval duration over the course of the intervention (O2+, 1736 ± 141 v. 700 ± 154 s; AMB, 1463 ± 598 v. 953 ± 253 s; P = 0.000); however, the increase experienced by O2+ was greater (P = 0.027). During low-intensity constant-work-rate cycling, the V̇O2 mean response time was shortened post compared to pre training (O2+, 34 ± 11 v. 44 ± 9 s; AMB, 39 ± 14 v. 45 ± 17 s; P = 0.000) while during high-intensity constant-work-rate cycling, time to exhaustion was increased (O2+, 1628 ± 163 v. 705 ± 133 s; AMB, 1073 ± 633 v. 690 ± 348 s; P = 0.002) and blood [lactate] response was decreased (O2+, 4.5 ± 0.9 v. 6.3 ± 1.4 mmol. L- 1; AMB, 4.5 ± 0.6 v. 5.2 ± 1.4 mmol. L- 1; P = 0.003). These positive adaptations were similar regardless of gas inspiration during training. CONCLUSION: Eight weeks of high-intensity interval training for patients with cystic fibrosis accelerated V̇O2 kinetics and increased time to exhaustion. This provides some evidence that these patients may benefit from this type of exercise. TRIAL REGISTRATION: This study was retrospectively registered in the ISRTCN registry on 22/06/2019 (#ISRCTN13864650).

Redox Homeostasis in Humans Exposed to Intermittent Hypoxia-Normoxia and to Intermittent Hypoxia-Hyperoxia.

Aim: Exposure to hypoxia is known to increase oxidative stress and to impair antioxidant defenses in humans. The aim of the study was to measure oxidative stress and antioxidant capacity in healthy humans after being acutely exposed to both intermittent hypoxia-normoxia (IHN) and intermittent hypoxia-hyperoxia (IHH). Methods: Twenty-one healthy, young male participants were exposed to both IHN and IHH (fraction of inspired oxygen [FIO2] 0.11 for up to 7 minutes followed by 3-5 minutes of exposure to normoxia (room air) or hyperoxia, FIO2 0.3-0.35) in a crossover design study. In each participant, oxidative stress and antioxidant capacity were measured before and after each exposure in both experimental conditions. Results: After IHN, compared with baseline, neither oxidative stress (289.1 ± 63.2 vs. 262.2 ± 85.2 UCarr) nor antioxidant capacity (2376.1 ± 452.9 vs. 2525.0 ± 400.7 UCor) was significantly different. After IHH, neither oxidative stress (285.1 ± 94.2 vs. 277.5 ± 86.7 UCarr) nor antioxidant capacity (2653.6 ± 492.7 vs. 2568.4 ± 427.4 UCor) was significantly different compared with baseline. When the two studied exposure modalities were compared, there was no significant difference between groups with respect to both oxidative stress and antioxidant capacity. Conclusions: These data suggest that exposing healthy individuals to short-term IHN and IHH does not increase oxidative stress and it does not impair antioxidant defenses.

Effectiveness of interventions aimed at improving dietary behaviours among people at higher risk of or with chronic non-communicable diseases: an overview of systematic reviews.

Programmes that promote dietary behaviour change for the prevention of chronic disease must include components that are rooted in best practice and associated with effectiveness. The purpose of this overview of systematic reviews was to examine the characteristics and dietary behaviour change outcomes of nutrition interventions among populations with or at risk of non-communicable chronic diseases. Systematic reviews of randomised controlled trials (RCTs) testing dietary behaviour change interventions published between January 2006 and November 2015 were identified via searches in Cochrane Library, PubMed, EMBASE and PsycINFO. Quality of reviews were appraised using AMSTAR. Dietary behaviour change and intervention details were extracted and systematically summarised. Fifteen articles met the inclusion criteria. Dietary behaviour changes in response to nutrition interventions were significant in over half of interventions. Reducing dietary fat and increasing fruits and vegetables were the most common behaviour changes. The characteristics of nutrition interventions and their relationship to effectiveness for dietary behaviour change among chronic disease or at-risk populations were reported inconsistently. However, associative evidence exists to support more frequent contacts and the use of specific behaviour change techniques. No clear relationships were found between effectiveness and intervention setting, mode of delivery or intervention provider, although some population-specific relationships were identified. Interventions that promote long-term maintenance of dietary behaviour changes are lacking in the literature. This comprehensive umbrella review identifies specific characteristics of interventions that are associated with effectiveness in interventions that promote dietary behaviour change among different at-risk populations. In order to maximise outcomes, public health, health promotion and healthcare organisations should consider these results in order to inform the development and improvement of nutrition programmes.

Intermittent Hypoxia-Hyperoxia Conditioning Improves Cardiorespiratory Fitness in Older Comorbid Cardiac Outpatients Without Hematological Changes: A Randomized Controlled Trial.

AIM: To compare a program based on intermittent hypoxia-hyperoxia training (IHHT) consisting of breathing hypoxic-hyperoxic gas mixtures while resting to a standard exercise-based rehabilitation program with respect to cardiorespiratory fitness (CRF) in older, comorbid cardiac outpatients. MATERIALS AND METHODS: Thirty-two cardiac patients with comorbidities were randomly allocated to IHHT and control (CTRL) groups. IHHT completed a 5-week program of exposure to hypoxia-hyperoxia while resting, CTRL completed an 8-week tailored exercise program, and participants in the CTRL were also exposed to sham hypoxia exposure. CRF and relevant hematological biomarkers were measured at baseline and after treatment in both groups. RESULTS: After intervention, CRF in the IHHT group was not significantly different (n = 15, 19.9 ± 6.1 mlO2 minutes-1 kg-1) compared with the CTRL group (n = 14, 20.6 ± 4.9 mlO2 minutes-1 kg-1). CRF in IHHT increased significantly from baseline (6.05 ± 1.6 mlO2 minutes-1 kg-1), while no difference was found in CTRL. Systolic and diastolic blood pressures were not significantly different between groups after treatment. Hemoglobin content was not significantly different between groups. Erythrocytes and reticulocytes did not change pre/post interventions in both experimental groups. CONCLUSIONS: IHHT is safe in patients with cardiac conditions and common comorbidities and it might be a suitable option for older patients who cannot exercise. A 5-week IHHT is as effective as an 8-week exercise program in improving CRF, without hematological changes. Further studies are needed to clarify the nonhematological adaptations to short, repeated exposure to normobaric hypoxia-hyperoxia.

Co-ingestion of protein or a protein hydrolysate with carbohydrate enhances anabolic signaling, but not glycogen resynthesis, following recovery from prolonged aerobic exercise in trained cyclists.

PURPOSE: The effect of carbohydrate (CHO), or CHO supplemented with either sodium caseinate protein (CHO-C) or a sodium caseinate protein hydrolysate (CHO-H) on the recovery of skeletal muscle glycogen and anabolic signaling following prolonged aerobic exercise was determined in trained male cyclists [n = 11, mean ± SEM age 28.8 ± 2.3 years; body mass (BM) 75.0 ± 2.3 kg; VO2peak 61.3 ± 1.6 ml kg-1 min-1]. METHODS: On three separate occasions, participants cycled for 2 h at ~ 70% VO2peak followed by a 4-h recovery period. Isoenergetic drinks were consumed at + 0 and + 2 h of recovery containing either (1) CHO (1.2 g kg -1 BM), (2) CHO-C, or (3) CHO-H (1.04 and 0.16 g kg-1 BM, respectively) in a randomized, double-blind, cross-over design. Muscle biopsies from the vastus lateralis were taken prior to commencement of each trial, and at + 0 and + 4 h of recovery for determination of skeletal muscle glycogen, and intracellular signaling associated with protein synthesis. RESULTS: Despite an augmented insulin response following CHO-H ingestion, there was no significant difference in skeletal muscle glycogen resynthesis following recovery between trials. CHO-C and CHO-H co-ingestion significantly increased phospho-mTOR Ser2448 and 4EBP1 Thr37/46 versus CHO, with CHO-H displaying the greatest change in phospho-4EBP1 Thr37/46. Protein co-ingestion, compared to CHO alone, during recovery did not augment glycogen resynthesis. CONCLUSION: Supplementing CHO with intact sodium caseinate or an insulinotropic hydrolysate derivative augmented intracellular signaling associated with skeletal muscle protein synthesis following prolonged aerobic exercise.

Adaptations following an intermittent hypoxia-hyperoxia training in coronary artery disease patients: a controlled study.

BACKGROUND: Repeated exposure to intermittent normobaric hypoxia improves exercise tolerance in cardiac patients. Little is known on the effects of intermittent normobaric hypoxia-hyperoxia exposure in coronary artery disease (CAD) patients (New York Heart Association II-III). HYPOTHESIS: IHHT improves exercise tolerance, cardiometabolic profile, and quality of life in CAD patients. METHODS: The study design was a nonrandomized, controlled, before-and-after trial. Forty-six CAD patients volunteered to take part in the study: a group of 27 patients undertook the intermittent hypoxia (O2 at 10%)-hyperoxia (O2 at 30%) training (IHHT), whereas a control group (CTRL) of 19 patients, who already completed an 8-week standard cardiac rehabilitation program, was allocated to sham-IHHT treatment (breathing room air, O2 at 21%). Exercise performance, blood and metabolic profiles, and quality of life (Seattle Angina Questionnaire [SAQ]) were measured before and after in the IHHT group (IHHG) and sham-IHHT in the CTRL group. RESULTS: The IHHG showed improved exercise capacity, reduced systolic and diastolic blood pressures, enhanced left ventricle ejection fraction, and reduced glycemia, but only at 1-month follow-up. Angina as a reason to stop exercising was significantly reduced after treatment and at 1-month follow-up. The IHHT SAQ profile was improved in the IHHG and not significantly different to the CTRL group after standard rehabilitation. The IHHG was also compared to the CTRL group at 1-month follow-up, and no differences were found. CONCLUSIONS: In CAD patients, an IHHT program is associated with improved exercise tolerance, healthier risks factors profile, and a better quality of life. Our study also suggests that IHHT is as effective as an 8-week standard rehabilitation program.

A programme based on repeated hypoxia-hyperoxia exposure and light exercise enhances performance in athletes with overtraining syndrome: a pilot study.

Overtraining syndrome (OTS) is a major concern among endurance athletes and is a leading cause in preventing them to perform for long periods. Intermittent exposure to hypoxia has been shown to be an effective way of improving performance without exercising. Aim of this pilot study was to evaluate intermittent hypoxia-hyperoxia training combined with light exercise as an intervention to facilitate athletes with OTS to restore their usual performance level. Thirty-four track and field athletes were recruited: 15 athletes with OTS volunteered to participate and undertook a conditioning programme consisting of repeated exposures to hypoxia (O2 at 10%) and hyperoxia (O2 at 30%) (6-8 cycles, total time 45 min-1 h), three times a week, delivered 1·5-2 h after a low-intensity exercise session (2 bouts of 30 min, running at 50% of VO2max with 10 min rest between bouts) over 4 weeks. Nineteen healthy track and field athletes volunteered to participate as a control group and followed their usual training schedule. Measurements before and after the intervention included exercise capacity, analysis of heart rate variability and hematological parameters. In athletes with OTS, a 4-week light exercise combined with intermittent hypoxia-hyperoxia training improved exercise performance (191·9 ± 26·9 W versus 170·8 ± 44·8 W in exercise capacity test, P = 0·01). Heart rate variability analysis revealed an improved sympatho-parasympathetic index (low frequency/high frequency ratio, 8·01 ± 7·51 before and 1·45 ± 1·71 after, P = 0·007). Hematological parameters were unchanged. Our pilot study showed that intermittent hypoxia-hyperoxia training and low-intensity exercise can facilitate functional recovery among athletes with OTS in a relatively short time.

School lunches in the Republic of Ireland: a comparison of the nutritional quality of adolescents' lunches sourced from home or purchased at school or 'out' at local food outlets.

OBJECTIVE: To compare the energy, nutrient and food group compositions of three sources of school-day lunches among students in five secondary schools in the Republic of Ireland (ROI). DESIGN: Cross-sectional study conducted between October 2012 and March 2013. Students completed self-report food diaries over two school days. The energy, nutrient, nutrient density and food group composition of school-day lunches from home, school and 'out' in local food outlets were compared using ANCOVA and Tukey's Honest Significant Difference post hoc analysis. SETTING: Five secondary schools in the ROI. SUBJECTS: Male and female students aged 15-17 years (n 305). RESULTS: Six hundred and fifteen lunches (376 home lunches, 115 school lunches and 124 lunches sourced 'out' in the local environment) were analysed. School and 'out' purchased lunches were significantly higher than packed lunches from home in energy (2047 kJ (489 kcal), 2664 kJ (627 kcal), 1671 kJ (399 kcal), respectively), total fat (23·5 g, 30·1 g, 16·6 g, respectively) and free (added) sugars (12·6 g, 19·3 g, 7·4 g, respectively). More home lunches contained more fruit, wholemeal breads, cheese and red meat than lunches from school or 'out'. Meat products, chips and high-calorie beverages were sourced more frequently at school or 'out' than home. Fibre and micronutrient contents of lunches from all sources were low. CONCLUSIONS: Home-sourced lunches had the healthiest nutritional profile in terms of energy and macronutrients. Foods high in energy, fat and free sugars associated with school and local food outlets are of concern given the public health focus to reduce their consumption. While school food should be improved, all sources of lunches need to be considered when addressing the dietary behaviours of secondary-school students.

Lessons learned about primary weight maintenance and secondary weight maintenance: results from a qualitative study.

BACKGROUND: Obesity is now a worldwide problem and Ireland is no exception with approximately two thirds of the adult population now overweight or obese. A recent report has found that 53% of Irish adults aged 50 years and over are classified as centrally obese and at substantially increased risk of metabolic complications. While most studies investigating weight maintenance have been conducted on those who have managed to lose weight and/or achieved weight loss maintenance (secondary weight maintainers), few studies have been undertaken to understand the attitudes, behaviours, motivations and strategies of those who maintain their weight within normal weight ranges over their lifetime, so called primary weight maintainers. This study aims to explore this issue through qualitative exploration of primary weight maintainers in an Irish University. METHODS: Seven focus groups were conducted (including three single interviews) with 17 participants in total across three different groups, 1) primary weight maintainers, 2) secondary weight maintainers, and 3) those unable to sustain or achieve weight loss. The interviews were transcribed and thematic analysis was applied to interpret the findings. RESULTS: After analyzing the participant's interviews, planning and organization or lack of, emerged as themes across the three groups in varying degrees. Strategizing, perseverance and willpower were seen as integral to weight maintenance and weight loss in groups one and two, these were lacking in group three. Prioritizing exercise and perseverance in maintaining a high level of activity was evident in groups one and two and was lacking in group three. Motivational influences were equal across the groups however, group three found it difficult to turn this into action. Group one had behavioural control of calorie intake maintaining a balance between week and weekend eating. Group three found it difficult to control calorie intake and portion size. Self-image differed across the three groups with cognitive dissonance evident amongst those in group three. CONCLUSIONS: This study showed that there are many factors that influence primary weight maintenance. Considering that we live in a society that is predominantly sedentary, predominantly overweight and with poor food choice options facing us every day, fighting our way through to ensure healthy weight maintenance requires active, conscious efforts. The factors identified in this study which are important in healthy weight maintenance are all potentially modifiable with life-coach, nutrition, exercise and cognitive interventions particularly if peer support and a whole family approach are incorporated.

The effects of aerobic exercise training at two different intensities in obesity and type 2 diabetes: implications for oxidative stress, low-grade inflammation and nitric oxide production.

AIMS: To investigate the effect of 16 weeks of aerobic training performed at two different intensities on nitric oxide (tNOx) availability and iNOS/nNOS expression, oxidative stress (OS) and inflammation in obese humans with or without type 2 diabetes mellitus (T2DM). METHODS: Twenty-five sedentary, obese (BMI > 30 kg/m2) males (52.8 ± 7.2 years); 12 controls versus 13 T2DM were randomly allocated to four groups that exercised for 30 min, three times per week either at low (Fat-Max; 30-40% VO(2max)) or moderate (T(vent); 55-65 % VO(2max)) intensity. Before and after training, blood and muscle samples (v. lateralis) were collected. RESULTS: Baseline erythrocyte glutathione was lower (21.8 ± 2.8 vs. 32.7 ± 4.4 nmol/ml) and plasma protein oxidative damage and IL-6 were higher in T2DM (141.7 ± 52.1 vs. 75.5 ± 41.6 nmol/ml). Plasma catalase increased in T2DM after T(vent) training (from 0.98 ± 0.22 to 1.96 ± 0.3 nmol/min/ml). T2DM groups demonstrated evidence of oxidative damage in response to training (elevated protein carbonyls). Baseline serum tNOx were higher in controls than T2DM (18.68 ± 2.78 vs. 12.34 ± 3.56 µmol/l). Training at T(vent) increased muscle nNOS and tNOx in the control group only. Pre-training muscle nNOS was higher in controls than in T2DMs, while the opposite was found for iNOS. No differences were found after training for plasma inflammatory markers. CONCLUSION: Exercise training did not change body composition or aerobic fitness, but improved OS markers, especially when performed at T(vent). Non-diabetics responded to T(vent) training by increasing muscle nNOS expression and tNOx levels in skeletal muscle while these parameters did not change in T2DM, perhaps due to higher insulin resistance (unchanged after intervention).

Differential nitric oxide levels in the blood and skeletal muscle of type 2 diabetic subjects may be consequence of adiposity: a preliminary study.

BACKGROUND AND AIMS: Nitric oxide (NO·) exerts key regulatory functions including vasodilation and glucose uptake. Thus reduced NO· levels are associated with insulin resistance and hypertension. In this preliminary work we aimed to measure the levels of NO· metabolites in serum and skeletal muscle of obese and non-obese subjects, with or without type 2 diabetes mellitus (T2DM). METHODS: Fifteen sedentary male participants [7 obese controls (C) vs 5 obese and 3 non-obese T2DM; age 54±9 years] were selected according to their BMI (>30 kg/m(2) for obese and 23-27 kg/m(2) for non-obese participants) and evaluated for fasted values of blood glucose, HbA1c, lipid profile, serum CRP (C-reactive protein), erythrocyte glutathione (GSH) metabolism, plasma adiponectin, leptin and cytokines (TNF-α and INFγ), serum and skeletal muscle nitric oxide metabolites (nitrite and nitrates; tNOx) and skeletal muscle nNOS and iNOS expression. Body composition was measured by whole body DEXA and muscle microbiopsy was performed in the vastus lateralis. RESULTS: We found that serum tNOx (total nitrite/nitrate; µmol/L) was lower in obese T2DM group (12.7±3.5) when compared with their controls (21.1±2.4), although the non-obese group presented higher concentration of tNOx (33.8±7.2). Skeletal muscle nNOS was higher in obese controls, lower in non-obese T2DM and undetected in obese T2DM. On the other hand, expression of iNOS had an inverse relationship with nNOS, showing higher expression in obese T2DM, decrease in non-obese T2DM and absence in obese control group. tNOx levels (µmol/mg protein) were decreased in the non-obese T2DM group (12.07±0.59) when compared with the obese control (21.68±6.2) and the obese T2DM group (26.3±7.26). CONCLUSION: We conclude that the decreased serum NO∙ production in obese T2DM patients seems to be associated with adipose mass as lower adiposity was associated with normal NO∙ which was reduced in the skeletal muscle of the non-obese T2DM patients. We suggest that the lower adiposity (and higher adiponectin) in non-obese T2DM could be responsible for differential levels of NO∙ production and insulin resistance.

The effects of beta1-adrenergic blockade on cardiovascular oxygen flow in normoxic and hypoxic humans at exercise.

At exercise steady state, the lower the arterial oxygen saturation (SaO(2)), the lower the O(2) return (QvO(2)). A linear relationship between these variables was demonstrated. Our conjecture is that this relationship describes a condition of predominant sympathetic activation, from which it is hypothesized that selective beta1-adrenergic blockade (BB) would reduce O(2) delivery (QaO(2)) and QvO(2). To test this hypothesis, we studied the effects of BB on QaO(2) and QvO(2) in exercising humans in normoxia and hypoxia. O(2) consumption VO(2), cardiac output Q, CO(2) rebreathing), heart rate, SaO(2) and haemoglobin concentration were measured on six subjects (age 25.5 +/- 2.4 years, mass 78.1 +/- 9.0 kg) in normoxia and hypoxia (inspired O(2) fraction of 0.11) at rest and steady-state exercises of 50, 100, and 150 W without (C) and with BB with metoprolol. Arterial O(2) concentration (CaO(2)), QaO(2) and QvO(2) were then computed. Heart rate, higher in hypoxia than in normoxia, decreased with BB. At each VO(2), Q was higher in hypoxia than in normoxia. With BB, it decreased during intense exercise in normoxia, at rest, and during light exercise in hypoxia. SaO(2) and CaO(2) were unaffected by BB. The QaO(2) changes under BB were parallel to those in Q.QvO(2) was unaffected by exercise in normoxia. In hypoxia the slope of the relationship between QaO(2) and VO(2) was lower than 1, indicating a reduction of QvO(2) with increasing workload. QvO(2) was a linear function of SaO(2) both in C and in BB. The line for BB was flatter than and below that for C. The resting QvO(2) in normoxia, lower than the corresponding exercise values, lied on the BB line. These results agree with the tested hypothesis. The two observed relationships between QvO(2) and SaO(2) apply to conditions of predominant sympathetic or vagal activation, respectively. Moving from one line to the other implies resetting of the cardiovascular regulation.

Energy cost of walking and running at extreme uphill and downhill slopes.

The costs of walking (Cw) and running (Cr) were measured on 10 runners on a treadmill inclined between -0.45 to +0.45 at different speeds. The minimum Cw was 1.64 +/- 0.50 J. kg(-1). m(-1) at a 1.0 +/- 0.3 m/s speed on the level. It increased on positive slopes, attained 17.33 +/- 1.11 J. kg(-1). m(-1) at +0.45, and was reduced to 0.81 +/- 0.37 J. kg(-1). m(-1) at -0.10. At steeper slopes, it increased to reach 3.46 +/- 0.95 J. kg(-1). m(-1) at -0.45. Cr was 3.40 +/- 0.24 J. kg(-1). m(-1) on the level, independent of speed. It increased on positive slopes, attained 18.93 +/- 1.74 J. kg(-1). m(-1) at +0.45, and was reduced to 1.73 +/- 0.36 J. kg(-1). m(-1) at -0.20. At steeper slopes, it increased to reach 3.92 +/- 0.81 J. kg(-1). m(-1) at -0.45. The mechanical efficiencies of walking and running above +0.15 and below -0.15 attained those of concentric and eccentric muscular contraction, respectively. The optimum gradients for mountain paths approximated 0.20-0.30 for both gaits. Downhill, Cr was some 40% lower than reported in the literature for sedentary subjects. The estimated maximum running speeds on positive gradients corresponded to those adopted in uphill races; on negative gradients they were well above those attained in downhill competitions.