Monitoring blood glucose during maximal intensity racing at national swimming competitions

Introduction: Glucose flux is known to be affected by exercise and many articles have been written concerning glucose rate of appearance, rate of disappearance, and of oxidation. Little is published on the response of blood glucose during maximal competition however. An investigation was undertaken to monitor Blood glucose during competition swimming and to see if there was any relationship to blood lactate and duration of effort. Methods: One hundred and four (104) swimmers from New Zealand world championship trials and South African Olympic trials (National events). Male (n=62) and Female (n=42) subjects were aged between 16 and 24 years. Peak in glucose and lactate levels was measured. The data were pooled for each event (50m to 1500m). Results: Representing race periods from 22 seconds to 18 minutes. The highest values were seen in the 800 and 1500m swims, with values between 8.5 and 11.2 mmol/L respectively. Findings: There appears to be a critical balance point around 45 to 50 seconds where the blood glucose value will remain at or around the resting value although this does not mean that there is not considerable glucose flux at this point. Across different time lines, at maximal effort, blood glucose appears to respond in a predictable way. This may prove useful for the identification of parameters for performance and for training also.