Olympians including Dutch marathon runner Abdi Nageeye are using a new tool they hope will boost their medal chances this summer: tiny monitors that attach to the skin to track blood glucose levels.

Continuous glucose monitors, or CGMs, were developed for use by diabetes patients but their makers, led by Abbott and Dexcom, also spy opportunities in sports and wellness.

The Paris Olympics, which start on July 26, are an opportunity to showcase the technology — even though there is as yet no proof it can boost athletic performance.