Validity of the Lumen® hand-held metabolic device to measure fuel utilization in healthy young adults.

BACKGROUND Metabolic carts measure the carbon dioxide produced and oxygen consumed from the breath in order to assess metabolic fuel usage (carbohydrates vs. fats). However, these systems are expensive, time-consuming, and only available in healthcare laboratory settings. A small hand-held device capable of measuring metabolic fuel via CO2 from exhaled air has been developed. Objective: To evaluate the validity of a novel hand-held device (Lumen®) for measuring metabolic fuel utilization in healthy young adults. OBJECTIVE To evaluate the validity of a novel hand-held device (Lumen®) for measuring metabolic fuel utilization in healthy young adults. METHODS Metabolic fuel usage was assessed in healthy participants (n = 33; age: 23.1 ± 3.9 y) via respiratory exchange ratio (RER) values obtained from a metabolic cart as well as %CO2 from the Lumen device. Measurements were performed at rest in two conditions: fasting, and after consuming 150 grams of glucose, in order to determine changes in metabolic fuel usage. Reduced major axis regression was performed as well as simple linear regression to test for agreement between RER and Lumen %CO2. RESULTS Both RER and Lumen %CO2 significantly increased after glucose intake (P < .001 for both) compared with fasting conditions, by 0.089 and 0.28, respectively. Regression analyses revealed an agreement between the two measurements (F(1,63) = 18.54; P < .001). CONCLUSIONS This study shows the validity of Lumen® to detect changes in metabolic fuel utilization in a comparable manner with a laboratory standard metabolic cart, providing the ability for real-time metabolic information for users under any circumstances. CLINICALTRIAL