Swedish Elite Swimmers Blood Glucose Levels During Recovery : A Descriptive Study Using Continuous Glucose Monitoring Systems

Abstract: Aim The aim of this study is to form a descriptive picture of Swedish national elite (SNLE) swimmers blood glucose (BG) levels in relation to their nutritional intake.  - Do SNLE swimmers have BG level in a normal range of ≥3.9 mmol/L when measured during a six-day period? - Is there a relationship between the SNLE swimmers blood glucose levels and how often or when they eat, and how they perceive their workout effort? Method Four test subjects, three females and one male, were recruited based on their competitive level, National Championship qualifying cut, geographical location, in Stockholm, and amount of swimming workouts completed weekly, seven on average. The test subjects wore a Continuous Glucose Monitor for a week and in addition a brief meal journal and perceived effort (ranking) of each workout was recorded. The data gathered was analyzed based on three main variables; time spent LOW (blood glucose level below 3.9mmol/L), amount of meals, and ranking. Results This study found that three out of four test subjects had occurrences of a LOW during the week. The test subjects spent on average 1.75 ±1.26 days with a LOW, the average time spent with a LOW per day was 37.3 ±29.7 minutes, the average amount during the whole week was 224 ±177 minutes, and the percent of the whole week spent with a LOW was 2.59 ±0.02%. In addition to this a correlation was found between (total) time spent LOW and (total) amount of meals with an R-value of 0.99, an R2 of 0.979, and P-value of 0.044. Conclusions The results showed that three test subjects spent time with a LOW and indicates similar results should be found in the general population of SNLE swimmers, however, this is definitely in need of further research. The results also indicated that there is a relationship between the amount of meals ingested and the BG level over the full six-day period but not on a daily basis. A regression analysis between (total) time spent LOW and (total) number of meals showed correlations with statistical significance, however, there was too small of a data sample (N=4) to draw conclusions based from this. This study forms a descriptive picture of the situation, which could serve as a platform for further research in this field, and give a first glance at the possible potential use of CGM systems within the sports nutrition field.