Cardiovascular and metabolic responses to passive hypoxic conditioning in overweight and mildly obese individuals.
Samarmar ChacarounAnna BorowikStephane DoutreleauElise BelaidiBernard WuyamRenaud TamisierJean-Louis PépinPatrice FloreSamuel VergesPublished in: American journal of physiology. Regulatory, integrative and comparative physiology (2020)
Although severe intermittent hypoxia (IH) is well known to induce deleterious cardiometabolic consequences, moderate IH may induce positive effects in obese individuals. The present study aimed to evaluate the effect of two hypoxic conditioning programs on cardiovascular and metabolic health status of overweight or obese individuals. In this randomized single-blind controlled study, 35 subjects (54 ± 9.3 yr, 31.7 ± 3.5 kg/m2) were randomized into three 8-wk interventions (three 1-h sessions per week): sustained hypoxia (SH), arterial oxygen saturation ([Formula: see text]) = 75%; IH, 5 min [Formula: see text] = 75% - 3 min normoxia; normoxia. Ventilation, heart rate, blood pressure, and tissue oxygenation were measured during the first and last hypoxic conditioning sessions. Vascular function, blood glucose and insulin, lipid profile, nitric oxide metabolites, and oxidative stress were evaluated before and after the interventions. Both SH and IH increased ventilation in hypoxia (+1.8 ± 2.1 and +2.3 ± 3.6 L/min, respectively; P < 0.05) and reduced normoxic diastolic blood pressure (-12 ± 15 and -13 ± 10 mmHg, respectively; P < 0.05), whereas changes in normoxic systolic blood pressure were not significant (+3 ± 9 and -6 ± 13 mmHg, respectively; P > 0.05). IH only reduced heart rate variability (e.g., root-mean-square difference of successive normal R-R intervals in normoxia -21 ± 35%; P < 0.05). Both SH and IH induced no significant change in body mass index, vascular function, blood glucose, insulin and lipid profile, nitric oxide metabolites, or oxidative stress, except for an increase in superoxide dismutase activity following SH. This study indicates that passive hypoxic conditioning in obese individuals induces some positive cardiovascular and respiratory improvements despite no change in anthropometric data and even a reduction in heart rate variability during IH exposure.
Keyphrases
- heart rate
- blood pressure
- heart rate variability
- blood glucose
- weight loss
- type diabetes
- nitric oxide
- glycemic control
- oxidative stress
- hypertensive patients
- adipose tissue
- physical activity
- metabolic syndrome
- body mass index
- diabetic rats
- hydrogen peroxide
- obese patients
- bariatric surgery
- weight gain
- open label
- double blind
- endothelial cells
- placebo controlled
- dna damage
- ms ms
- high intensity
- public health
- smoking cessation
- heart failure
- machine learning
- big data
- signaling pathway
- early onset
- left ventricular
- insulin resistance
- skeletal muscle
- intensive care unit
- endoplasmic reticulum stress
- drug induced
- atrial fibrillation
- human milk
- body composition
- study protocol