Arnt E. Tjønna

Aerobic interval training reduces cardiovascular risk factors more than a multitreatment approach in overweight adolescents

The aim of the present study was to compare the effects of a multidisciplinary approach (MTG) and aerobic interval training (AIT) on cardiovascular risk factors in overweight adolescents. A total of 62 overweight and obese adolescents from Trøndelag County in Norway, referred to medical treatment at St Olavs Hospital, Trondheim, Norway, were invited to participate. Of these, 54 adolescents (age, 14.0 +/- 0.3 years) were randomized to either AIT (4 x 4 min intervals at 90% of maximal heart rate, each interval separated by 3 min at 70%, twice a week for 3 months) or to MTG (exercise, dietary and psychological advice, twice a month for 12 months). Follow-up testing occurred at 3 and 12 months. VO(2max) (maximal oxygen uptake) increased more after AIT compared with MTG, both at 3 months (11 compared with 0%; P<0.01) and 12 months (12 compared with -1%; P<0.01). AIT enhanced endothelial function compared with MTG at both 3 months (absolute change, 5.1 compared with 3.9%; P<0.01) and 12 months (absolute change, 6.3 compared with 1.0%; P<0.01). AIT was favourable compared with MTG in reducing BMI (body mass index), percentage of fat, MAP (mean arterial blood pressure) and increasing peak oxygen pulse. In addition, AIT induced a more favourable regulation of blood glucose and insulin compared with MTG. In conclusion, the novel findings of the present proof-of-concept study was that 3 months of twice weekly high-intensity exercise sessions reduced several known cardiovascular risk factors in obese adolescents more than that observed after a multitreatment strategy, which was initiated as hospital treatment. Follow-up at 12 months confirmed that AIT improved or maintained these risk factors to a better degree than MTG.

Both aerobic endurance and strength training programmes improve cardiovascular health in obese adults.

Regular exercise training is recognized as a powerful tool to improve work capacity, endothelial function and the cardiovascular risk profile in obesity, but it is unknown which of high-intensity aerobic exercise, moderate-intensity aerobic exercise or strength training is the optimal mode of exercise. In the present study, a total of 40 subjects were randomized to high-intensity interval aerobic training, continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks, three times/week. The high-intensity group performed aerobic interval walking/running at 85-95% of maximal heart rate, whereas the moderate-intensity group exercised continuously at 60-70% of maximal heart rate; protocols were isocaloric. The strength training group performed high-intensity leg press, abdominal and back strength training. Maximal oxygen uptake and endothelial function improved in all groups; the greatest improvement was observed after high-intensity training, and an equal improvement was observed after moderate-intensity aerobic training and strength training. High-intensity aerobic training and strength training were associated with increased PGC-1alpha (peroxisome-proliferator-activated receptor gamma co-activator 1alpha) levels and improved Ca(2+) transport in the skeletal muscle, whereas only strength training improved antioxidant status. Both strength training and moderate-intensity aerobic training decreased oxidized LDL (low-density lipoprotein) levels. Only aerobic training decreased body weight and diastolic blood pressure. In conclusion, high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function. An important contribution towards improved aerobic work capacity, endothelial function and cardiovascular health originates from strength training, which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform.

High-Intensity Interval Exercise Effectively Improves Cardiac Function in Patients With Type 2 Diabetes Mellitus and Diastolic Dysfunction: A Randomized Controlled Trial

Left ventricular diastolic dysfunction (DD) may lead to heart failure and is found in approximately 50%xa0of asymptomatic patients with type 2 diabetes mellitus (T2DM). Little is known about the effect of exercise on DD in T2DM [(1)][1], but moderate-intensity exercise (MIE) seems insufficient to

Aerobic high intensity one and two legs interval cycling in chronic obstructive pulmonary disease: the sum of the parts is greater than the whole

The purpose of this study was to investigate whether individual leg cycling could produce higher whole body peak oxygen uptake (VO2peak) than two legs cycling during aerobic high intensity interval training in chronic obstructive pulmonary disease (COPD) patients. Nineteen patients trained in 24 supervised cycling sessions either by one leg training (OLT) (nxa0=xa012) or by two legs training (TLT) (nxa0=xa07) at 4xa0×xa04xa0min intervals at 85–95% of peak heart rate. Whole body VO2peak and peak work rate increased significantly by 12 and 23% in the OLT, and by 6 and 12% in the TLT from pre- to post-training, respectively, and were significantly greater in the OLT than the TLT (Pxa0<xa00.05). The present study demonstrates that one leg aerobic high intensity interval cycling is superior to two legs in increasing whole body VO2peak, indicating a muscle rather than a cardiovascular limitation to VO2peak in these COPD patients.

Carbon Monoxide Levels Experienced by Heavy Smokers Impair Aerobic Capacity and Cardiac Contractility and Induce Pathological Hypertrophy

Cigarette smoke contains hundreds of potentially toxic compounds and is an important risk factor for cardiovascular disease. However, the key components responsible for endothelial and myocardial dysfunction have not been fully identified. The objective of the present study was to determine the cardiovascular effects of long-term inhalation of carbon monoxide (CO) administrated to give concentrations in the blood similar to those observed in heavy smokers. Female rats were exposed to either CO or air (control group) (n = 12). The CO group was exposed to 200 ppm CO (100 h/wk) for 18 mo. Rats exposed to CO had 24% lower maximal oxygen uptake, longer (145 vs. 123 μ m) and wider (47 vs. 25 μ m) cardiomyocytes, reduced cardiomyocyte fractional shortening (12 vs. 7%), and 26% longer time to 50% re-lengthening than controls. In addition, cardiomyocytes from CO-exposed rats had 48% lower intracellular calcium (Ca2 +) amplitude, 22% longer time to Ca2 + decay, 34% lower capacity of sarcoplasmic reticulum Ca2 +-ATPase (SERCA2a), and 37% less t-tubule area compared to controls. Phosphorylation levels of phospholamban at Ser16 and Thr17 were significantly reduced in the CO group, whereas total concentration of phospholamban and SERCA2a were unchanged. Cardiac atrial natriuretic peptide, vascular endothelial growth factor, cyclic guanosine monophosphate, calcineurin, calmodulin, pERK, and pS6 increased, whereas pAkt and pCaMKII δ remained unchanged by CO. Endothelial function and systemic blood pressure were not affected by CO exposure. Long-term CO exposure reduces aerobe capacity and contractile function and leads to pathological hypertrophy. Impaired Ca2 + handling and increased growth factor signaling seem to be responsible for these pathological changes.

Transcriptional changes in blood after aerobic interval training in patients with the metabolic syndrome

Background Regular physical activity has beneficial effects on the metabolic syndrome. Eleven metabolic syndrome patients performing 16 weeks of aerobic interval training, significantly reduced their risk of cardiovascular disease, in terms of improved VO2max, endothelial function, blood pressure, insulin signaling, and plasma lipid composition. The knowledge on underlying mechanism of exercise-induced improvements is sparse, and a broad spectrum of methods is needed to gain more insight. Design The aim was, for the first time, to determine whether transcriptional changes occur in blood cells of metabolic syndrome patients after participating in an exercise program. Methods Blood was collected in PAXgene and EDTA tubes before and after 16 weeks of exercise. RNA was extracted and run on microarrays. Results Eleven biological processes and molecular functions were upregulated after exercise, whereas seven were downregulated. Blood clotting, cell adhesion, and steroid metabolism were among the downregulated processes, whereas steroid hormone-mediated signaling was upregulated. Downregulated protein levels of arginase 1 and von Willebrand factor confirmed microarray results. Conclusion Increased transcription of genes involved in steroid hormone-mediated signaling, decreased levels of arginase 1, and reduced transcription of genes involved in cell adhesion, and blood clotting are likely to be involved in exercise-induced improvements of endothelial function, and improved cardiovascular risk profile of metabolic syndrome patients. These findings have provided new insights on exercise-induced improvement of cardiovascular health. Eur J Cardiovasc Prev Rehabil 16:47-52

Effect of high-intensity interval training on fitness, fat mass and cardiometabolic biomarkers in children with obesity: a randomised controlled trial

BackgroundPaediatric obesity significantly increases the risk of developing cardiometabolic diseases across the lifespan. Increasing cardiorespiratory fitness (CRF) could mitigate this risk. High-intensity interval training (HIIT) improves CRF in clinical adult populations but the evidence in paediatric obesity is inconsistent.ObjectivesThe objectives of this study were to determine the efficacy of a 12-week, HIIT intervention for increasing CRF and reducing adiposity in children with obesity.MethodsChildren with obesity (nxa0=xa099, 7–16xa0years old) were randomised into a 12-week intervention as follows: (1) HIIT [nxa0=xa033, 4xa0×xa04-min bouts at 85–95% maximum heart rate (HRmax), interspersed with 3xa0min of active recovery at 50–70% HRmax, 3xa0times/week] and nutrition advice; (2) moderate-intensity continuous training (MICT) [nxa0=xa032, 44xa0min at 60–70% HRmax, 3xa0times/week] and nutrition advice; and (3) nutrition advice only (nutrition) [nxa0=xa034]. CRF was quantified through a maximal exercise test (

Assessment of the 5-Minute Oxygen Uptake Efficiency Slope in Children With Obesity

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