Pulmonary gas exchange in response to rebreathing-induced hypoxia

Date

2023-04-18

Authors

Guei, Jamie Gaytan

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Abstract

Rebreathing-induced hypoxia elicits changes in pulmonary gas exchange variables. PURPOSE: This report aims to determine the changes in pulmonary gas exchange variables in response to a rebreathing-induced hypoxia protocol in individuals who are healthy, have prediabetes, or have type 2 diabetes. METHODS: Fifteen participants (M: 9, age 45 ± 17 years, body mass index: 34.2 ± 8.0 kg/m²) visited the laboratory. A 2-hour, 75 g oral glucose tolerance test was conducted during the study visit while simultaneously performing a rebreathing-induced hypoxia protocol. Venous blood samples were collected 0, 30-, 60-, 90-, and 120-min following ingestion of the glucose drink to measure plasma glucose and insulin levels. The rebreathing-induced hypoxia protocol consisted of two series of five 2-min rebreathing bouts in a low-volume, closed circuit system interspersed with two minutes of breathing room air. The first and second series of rebreathing bouts were performed within the first 30 min and 30-60 min after ingesting the glucose drink, respectively. Pulmonary gas exchange was measured using a metabolic cart. RESULTS: End-tidal oxygen, fraction of inspired oxygen, and respiratory rate decreased during rebreathing-induced hypoxia. Tidal volume, minute ventilation, oxygen uptake, and end-tidal carbon dioxide increased during rebreathing-induced hypoxia. CONCLUSION: Rebreathing-induced hypoxia elicits changes in pulmonary gas exchange in individuals who are healthy, have prediabetes, or have type 2 diabetes.

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