Abstract:
Background: Previously, 24-hour resting metabolic rate (RMR) or exercise energetics (EX) were determined utilizing metabolic carts, with typical measurement durations from 30 to 45-minutes, respectively (Balci et al, 2021; Guerrero et al, 2020). Major disadvantages of metabolic carts are the subject’s physical connection to instrumentation using ventilated hoods or head-gear and the lack of calculation of carbohydrate and lipid oxidation. Moreover, metabolic carts themselves can produce highly inaccurate results (Rising et al, 2015; Rising et al, 2016). Finally, physical connection of the subject to instrumentation can cause anxiety (Malone, 2002), contributing to additional errors in metabolic results. Previously, specific whole room indirect calorimeters (WRIC’s) have been validated for the determination of 24-hour RMR (Rising et al, 2015) and EX (Rising et al 2016) from 60-minute measurement durations. The purpose of this presentation is to show that accurate metabolic measurements of 24-hour RMR and 1-hour EX can be obtained in just 30-minutes, similar that of metabolic carts.
Methods: For simulated 24-hour RMR, ten 30-minute propane (99.5 % purity) combustion tests were performed using a standard torch (Model UL2317, Bernzomatic Inc., Chilton, WI USA). Burn rate (BR; g/min) were determined by recording the propane weight prior to and after test completion using an analytical balance (Mettler Toledo Model MS1602S/03, Mettler Toledo LLC, Columbus, OH USA). For simulated EX, ten thirty-minute propane (99.5 % purity) combustion tests were performed using a larger burner (Coleman Model 5431B, The Colman Company, Wichita, KS USA) to simulate exercise. The BR was determined as described previously. All respiratory exchange measurements were derived utilizing the Promethion (Model GA3m2/FG250) integrated system (Sable Systems International, North Las Vegas NV USA). Instrumentation was calibrated according to the manufacturer’s instructions.
The modified Weir equation was utilized to calculate energy expenditure (EE; kcal), assuming 66 mg/min protein oxidation. Ventilation rates (V;liters) of oxygen (VO2), carbon dioxide (VCO2) and the respiratory quotient (RQ; VCO2/VO2) were also calculated on a per minute basis. Finally, oxidation rates for glucose and lipids were also calculated (Kelly and Basset, 2017). Thirty-minute data were then extrapolated to 24-hours for RMR and one-hour for EX and compared to propane stoichiometry.
Statistical analysis was performed utilizing SPSS (Ver 27, Chicago, IL).
Conclusions: Accurate determinations of 24-hour RMR can be obtained from just a 30- minute metabolic measurement. Furthermore, like 24-hour RMR, one-hour EX can be accurately obtained from just a 30-minute metabolic measurement. Finally, these results suggest that WRIC’s may be suitable as an adjunct for obesity treatment and enhancement of athletic performance, with measurement durations similar to that of metabolic carts.
Audience takeaway notes:
- The audience will have an understating of the ease of using whole room indirect calorimetry as an adjunct for any kind of treatment program where accurate recording of metabolic rate is necessary. They will also understand the advantages of whole room indirect calorimetry over that of metabolic carts, both in terms of subject comfort and accuracy of metabolic measurements. Furthermore, anyone in the audience who is involved in the exercise sciences will understand how accurate measurements of exercise energetics can enhance athletic performance. This is a much underserved area of the metabolic sciences in terms of whole room indirect calorimetry. They will see the versatility of whole room indirect calorimetry in terms of the metabolic measurements for just about any physical activity, unlike that of metabolic carts that are usually restricted to just running or cycling, due to the subject connection to the instrumentation.
- Accurate metabolic measurements could shorten treatment durations for obesity thus saving time and money for those professionals involved. Furthermore, this will allow greater patient thru put thus possibly increasing revenue. Finally, with greater accuracy and subject comfort, success rates in these various obesity treatment programs and athletic training will be greatly increased.
- The information presented to the audience will allow the implementation of metabolic measurements in many disease states such as cancer, Huntington’s disease or metabolic syndrome. Faculty in various departments such as Endocrinology, Physiology, or any other discipline, may benefit from accurate metabolic measurements for their research.
- The increased accuracy of metabolic measurements, without the need for subject connection to instrumentation, opens a wealth of possibilities in terms of any kind of research involving nutritional enhancement, athletic performance in various sports as well as the understanding of the metabolic profiles of patients whom have, or are being treated for various diseases such as cancer, diabetes, obesity, or any other medical condition.
- The versatility of whole room indirect calorimetry allows metabolic measurements under many experimental conditions that were not possible with metabolic carts. Furthermore, the ease of use and subject comfort of whole room calorimetry will allow metabolic measurements in larger numbers of subjects and better attrition rates for various studies.
