Davide Susta

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.

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.

Early prediction of the highest workload in incremental cardiopulmonary tests

Incremental tests are widely used in cardiopulmonary exercise testing, both in the clinical domain and in sport sciences. The highest workload (denoted Wpeak) reached in the test is key information for assessing the individual body response to the test and for analyzing possible cardiac failures and planning rehabilitation, and training sessions. Being physically very demanding, incremental tests can significantly increase the body stress on monitored individuals and may cause cardiopulmonary overload. This article presents a new approach to cardiopulmonary testing that addresses these drawbacks. During the test, our approach analyzes the individual body response to the exercise and predicts the Wpeak value that will be reached in the test and an evaluation of its accuracy. When the accuracy of the prediction becomes satisfactory, the test can be prematurely stopped, thus avoiding its entire execution. To predict Wpeak, we introduce a new index, the CardioPulmonary Efficiency Index (CPE), summarizing the cardiopulmonary response of the individual to the test. Our approach analyzes the CPE trend during the test, together with the characteristics of the individual, and predicts Wpeak. A K-nearest-neighbor-based classifier and an ANN-based classier are exploited for the prediction. The experimental evaluation showed that the Wpeak value can be predicted with a limited error from the first steps of the test.

Predicting the highest workload in cardiopulmonary test

Cardiopulmonary exercise testing is an objective method to evaluate both the cardiac and pulmonary functions. It is used in different application domains, ranging from the clinical domain to sport sciences, to assess possible cardiac failures as well as athete performance. The highest workload reached in the test is a key information to evaluate the individuals physiological characteristics, to plan rehabilitation and/or training sessions. However, these tests are physically very demanding and may expose the tested individual to cardiopulmonary overload. This paper presents a new approach that allows an early prediction of the highest workload that will be reached in the cardiopulmonary test. The test can be prematurely stopped, avoiding its entire execution. The proposed approach relies on a new index, the CardioPulmonary Efficiency Index, which describes the cardiopulmonary response of an individual by summarizing the physiological signals monitored during the test. A k-Nearest Neighbor based classifier analyzes the index trend during the test, together with the characteristics of the individual, and predicts the highest workload. Preliminary experiments, performed on a real dataset provided by the CSA Sport Training Center, showed that the proposed approach is able to effectively predict the highest workload with a limited error since the first steps of the test.

Adaptations following an intermittent hypoxia-hyperoxia training in coronary artery disease patients: a controlled study: Cardiopulmonary and metabolic adaptations after intermittent hypoxia-hyperoxia training

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).

Predicting Cardiopulmonary Response to Incremental Exercise Test

Cardiopulmonary exercise testing is a non-invasive method widely used to monitor various physiological signals, describing the cardiac and respiratory response of the patient to increasing workload. Since this method is physically very demanding, innovative data analysis techniques are needed to predict patient response thus lowering body stress and avoiding cardiopulmonary overload. This paper proposes the Cardiopulmonary Response Prediction (CRP) framework for early predicting the physiological signal values that can be reached during an incremental exercise test. The learning phase creates different models tailored to specific conditions (i.e., single-test and multiple-test models). Each model can be exploited in the real-time stream prediction phase to periodically predict, during the test execution, signal values achievable by the patient. Experimental results on a real dataset showed that CRP prediction is performed with a limited and acceptable error.

Intermittent Hypoxia-Hyperoxia exposures Improve Cardiometabolic Profile, Exercise Tolerance and Quality of Life: A Preliminary Study in Cardiac Patients

Study design: randomized controlled before-and-after and in follow-up trial. Forty-six CAD patients volunteered to take part in the study: a group of 27 patients undertook an Intermittent Hypoxia (O2 at 10%)-Hyperoxia (O2 at 30%) Training (IHHT), while a control group (CTRL) of 19 patients was allocated to sham IHHT treatment (breathing via face mask by room air, O2 at 21%). Exercise performance, blood and metabolic profile, quality of life (MOS SF-36, Seattle Angina Questionnaire, SAQ) were measured before and after IHHT/sham IHHT in both groups; the intervention group was also assessed one month after completing the IHHT.

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.

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.

Anthropometry with adolescents: participation & perceptions

With increasing overweight and obesity among adolescents in Ireland (1) , it is generally agreed that monitoring trends in body weight is important to effectively plan management and prevention strategies. We must also take account of what adolescents are telling us about body image and how it impacts their lives (2) . Our study wished to address the experience of an adolescent group having their weight, waist circumference and height taken as part of a research study. Five Irish postprimary schools enrolled fourth year classes (aged 15–17 years) in the study. Weight, height and waist circumference were measured on the school grounds by trained health professionals including dietitians, nutritionists, nurses and doctors. Screens provided privacy for participants while measurements were being taken. At the end of the study period, all students were asked to complete an anonymous participant-evaluation questionnaire. Seventy-two percent (362/500) participated in the anthropometric measurements. Response rates were higher in single gender schools and ranged from 58 % (120/206) in a mixed gender school to 86 % (67/78) and 91 % (41/45) in a female only and male only school respectively. Principal reasons given for not participating were lack of interest in the study, absenteeism, and feeling uncomfortable about being measured. Eighty-five percent of students (308/362) who took part in anthropometry completed an evaluation survey. Students were asked to rate the experience as ‘positive’, ‘negative’ or ‘neither positive or negative’ and comment on their response.