Intermittent Normobaric Hypoxia Alters Substrate Partitioning and Muscle Oxygenation in Obese Individuals: Implications for fat burning

Am J Physiol Regul Integr Comp Physiol. 2023 Dec 4. doi: 10.1152/ajpregu.00153.2023. Online ahead of print.ABSTRACTThis single-blind, crossover study aimed to measure and evaluate the short-term metabolic responses to continuous and intermittent hypoxic patterns in individuals with obesity. Indirect calorimetry was used to quantify changes in resting metabolic rate (RMR), carbohydrate (CHOox, %CHO) and fat oxidation (FATox, %FAT) in nine individuals with obesity pre- and post-: (i) breathing normoxic air [normoxic sham control (NS-control)]; (ii) breathing continuous hypoxia (CH); or (iii) breathing intermittent hypoxia (IH). A mean peripheral oxygen saturation (SpO2) of 80-85% was achieved over a total of 45 minutes of hypoxia. Throughout each intervention pulmonary gas exchanges - oxygen consumption ( ), carbon dioxide production ( - and deoxyhaemoglobin concentration ( [HHb]) in the vastus lateralis were measured. Both RMR and CHOox measured pre- and post-interventions were unchanged following each treatment: NS-control; CH; or IH (all p > 0.05). Conversely, a significant increase in FATox was evident between pre- and post-IH (+44%, p = 0.048). While the mean [HHb] values significantly increased during both IH and CH (p<0.05), the greatest zenith of [HHb] was achieved in IH compared to CH (p = 0.002). Furthermore, there was a positive correlation between ∆[HHb] and the shift in FATox measured pre- and post-intervention. It is suggested that during IH the increased ...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Source Type: research