Normobaric hypoxic conditioning to maximize weight loss and ameliorate cardio-metabolic health in obese populations: a systematic review
Autor: | Olivier Girard, Liam Hobbins, Steve Hunter, Nadia Gaoua |
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Rok vydání: | 2017 |
Předmět: |
Adult
Male medicine.medical_specialty Physiology medicine.medical_treatment 030204 cardiovascular system & hematology Mice 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Risk Factors Weight loss Altitude training Physiology (medical) Weight Loss Prevalence medicine Animals Humans Obesity Ischemic Preconditioning business.industry Cholesterol Insulin Heart 030229 sport sciences Hypoxia (medical) medicine.disease Rats Oxygen Treatment Outcome Blood pressure chemistry Physical therapy Conditioning Female medicine.symptom Energy Metabolism business |
Zdroj: | American Journal of Physiology-Regulatory, Integrative and Comparative Physiology. 313:R251-R264 |
ISSN: | 1522-1490 0363-6119 |
Popis: | Normobaric hypoxic conditioning (HC) is defined as exposure to systemic and/or local hypoxia at rest (passive) or combined with exercise training (active). HC has been previously used by healthy and athletic populations to enhance their physical capacity and improve performance in the lead up to competition. Recently, HC has also been applied acutely (single exposure) and chronically (repeated exposure over several weeks) to overweight and obese populations with the intention of managing and potentially increasing cardio-metabolic health and weight loss. At present, it is unclear what the cardio-metabolic health and weight loss responses of obese populations are in response to passive and active HC. Exploration of potential benefits of exposure to both passive and active HC may provide pivotal findings for improving health and well being in these individuals. A systematic literature search for articles published between 2000 and 2017 was carried out. Studies investigating the effects of normobaric HC as a novel therapeutic approach to elicit improvements in the cardio-metabolic health and weight loss of obese populations were included. Studies investigated passive ( n = 7; 5 animals, 2 humans), active ( n = 4; all humans) and a combination of passive and active ( n = 4; 3 animals, 1 human) HC to an inspired oxygen fraction ([Formula: see text]) between 4.8 and 15.0%, ranging between a single session and daily sessions per week, lasting from 5 days up to 8 mo. Passive HC led to reduced insulin concentrations (−37 to −22%) in obese animals and increased energy expenditure (+12 to +16%) in obese humans, whereas active HC lead to reductions in body weight (−4 to −2%) in obese animals and humans, and blood pressure (−8 to −3%) in obese humans compared with a matched workload in normoxic conditions. Inconclusive findings, however, exist in determining the impact of acute and chronic HC on markers such as triglycerides, cholesterol levels, and fitness capacity. Importantly, most of the studies that included animal models involved exposure to severe levels of hypoxia ([Formula: see text] = 5.0%; simulated altitude >10,000 m) that are not suitable for human populations. Overall, normobaric HC demonstrated observable positive findings in relation to insulin and energy expenditure (passive), and body weight and blood pressure (active), which may improve the cardio-metabolic health and body weight management of obese populations. However, further evidence on responses of circulating biomarkers to both passive and active HC in humans is warranted. |
Databáze: | OpenAIRE |
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