The use of glucose rich rehydrating liquids is widely accepted and practiced by both recreational and professional athletes alike, but the results of a study done in Australia suggest that the addition of maize starch may be even better.
A group of researchers from Adelaide, Australia's Flinders University conducted a study which gave footballers a high amylose maize starch and glucose drink to investigate the effect it would have on overall hydration.
A total of 27 Australian football players participated in the study performed over the course of four days; two control days and two days actively using the combination drink.
All participants were club players from Adelaide football club currently undertaking preseason football training in the hot summer months, outdoors, where temperatures routinely reach 90°F.
Control days involved athletes consuming their usual hydration drink of choice, while interventional days included athletes consuming 100 g of the high amylose maize starch in 600 mL of flavored milk the evening before, in an effort to accomplish preloading.
On the subsequent day of training, participants then consumed a blended sports drink containing 5 g/L of glucose and 45 g/L of the resistant maize starch.
Athletes that consumed the combination of maize starch and glucose as part of their hydration strategies experienced not only a better hydration status post training, but also at the commencement.
These observations were made by measuring their hematocrit volume and body weight (as acute weight loss is indicative of dehydration)
In addition to improved hydration status before and after training, the approach was also found to be a better one at the commencement of training, superior to glucose alone .
Rationale For The Study
Even though glucose was accepted as a suitable part for the role of rehydration drink, it was less than ideal. Based on medical observations, the amount of glucose found in commercially available drinks are far higher than necessary for effective rehydration.
It was even found that high glucose concentrations in the small intestine, at a concentration exceeding 80mmol/liter impairs water resorption, contributing to further hypo hydration.
The new combination rehydration drink seeks to reduce the amount of glucose deemed necessary, improving overall hydration status in the process and preventing impairment of exercise performance 
Limitations Of The Study
Owing to the fact that the study was only single blinded, a fair amount of bias could have existed when recording findings. For instance, athletes knew what they were consuming and on which days, and could have compensated by increasing the amount of liquid consumed on those days, along with the rehydrating drink.
In addition, a total of four subjects experienced abdominal discomfort after preloading with the 100 g maize drink the evening prior to training, which mandated a reduction of the dose to 50 g (as necessary). These considerations need to be kept in mind when formulating new studies.
Based on the magnitude of observed findings, it appears promising that such a combination drink may provide a superior alternative for improving hydration status in the near future.
However, further studies are needed to confirm these findings and to take into account the new findings obtained from this study.
Dehydration to the extent of just 2% can have a profound impact, impairing both physical and cognitive performance . This study shows the exciting potential the combination of maize starch and glucose can have on performance.
- Sinead Mary O'Connell et al. Comparison of a sports-hydration drink containing high amylose starch with usual hydration practice in Australian rules footballers during intense summer training. Journal of the International Society of Sports Nutrition 2018 doi: 10.1186/s12970-018-0253-8
- Barr SL. (1999) Effects of dehydration on exercise performance. Can J Appl Physiol. 1999 Apr; 24(2):164-72.
- Shaun K Riebl, Brenda M. Davy (2013) The Hydration Equation: Update on Water Balance and Cognitive Performance. ACSMs Health Fit J. 2013 November/December; 17(6): 21–28. doi:[10.1249/FIT.0b013e3182a9570f]