MEASUREMENT OF BREATH ACETONE IN THE DETECTION OF LOW CARBOHYDRATE AVAILABILITY FOLLOWING IMPLEMENTATION OF “TRAIN LOW” STRATEGIES

Abstract

Enhancing the metabolism of athletes can be achieved through the manipulation of nutrition and exercise variables. Muscle biopsies are currently viewed as the ‘gold-standard’ for assessing muscle glycogen levels of athletes. However, the process of obtaining a muscle biopsy is invasive and takes a considerable time to analyse. Following research that has implemented muscle biopsies, it has been suggested that an acute reduced carbohydrate intake in conjunction with a suitable training intensity (known as “training low”) has shown to elicit conducive metabolic adaptations to increase the sustainability and production of adenosine triphosphate (ATP) to support endurance athletes. The overarching purpose of this research was to establish and refine a suitable protocol, which could be employed to analyse the effectiveness of a number of “train low” strategies at eliciting low carbohydrate availability in endurance athletes. Six key aims were identified to guide the research, which focused on the integration of chemistry and sports science equipment, identifying the most effective sequence to collect the measurements required, and comparing and understanding two breath acetone (BrAce) detectors for assessing carbohydrate availability. This thesis presented a methodological-development study to address the purpose and aims through a series of four pilot studies. The two BrAce detectors included a Cavity Enhanced Laser Induced Fluorescence (CELIF) prototype (made by the Chemistry Department at Durham University) and a Ketonix® BrAce detector, which is currently in the breath analyser market. In addition to the BrAce detectors, other metabolic measurements included capillary blood glucose, betahydroxybutyrate and gas analysis (i.e., respiratory exchange ratio). The pilot studies concluded with an experimental pilot, which involved an endurance athlete (male, ultra-endurance, running; age: 38 years; stature: 1.76 m; body mass: 66.1 kg), who followed the agreed protocol. Taking the range of measurements sequentially rather than in parallel
was the most effective, with the CELIF BrAce concentrations reflecting the values of the accompanying metabolic measures more than the Ketonix®, with the Ketonix® providing a wider variance of measurements within and between participants. The participant in the experimental trial was unable to complete the exercise protocol after following the “train low” strategies. Overall, the agreed protocol worked effectively, with some revaluation required for elements of the equipment and protocol. The CELIF BrAce detector provided an indication that it detects carbohydrate availability more effectively than the Ketonix®. However, further refining and development is required to improve the prototype’s effectiveness of detecting low carbohydrate availability.