Scientists are working on a new biosensor, applied to the human skin like a temporary tattoo, that can alert marathoners, competitive bikers and other “extreme” athletes that they’re about to “bonk,” or “hit the wall.” The study, in ACS’ journal Analytical Chemistry, describes the first human tests of this sensor, which also could help soldiers and others who engage in intense exercise — and their trainers — monitor stamina and fitness.
The sensor monitors lactate, a form of lactic acid released in sweat. Lactate forms when the muscles need more energy than the body can supply from aerobic respiration. The body then shifts to anaerobic metabolism, producing lactic acid and lactate. That helps for a while, but lactate builds up in the body, causing extreme fatigue and the infamous “bonking out,” where an athlete just cannot continue. Current methods of measuring lactate are cumbersome, require blood samples or do not give instant results. Joseph Wang and his colleagues sought to develop a better approach.
In their study they describe the first human tests of a lactate sensor applied to the skin like a temporary tattoo that stays on and flexes with body movements. Tests on 10 human volunteers showed that the sensor accurately measured lactate levels in sweat during exercise. The scientists say that such skin-worn metabolite biosensors could lead to useful insights into physical performance and overall physiological status, hence offering considerable promise for diverse sport, military, and biomedical applications.
Future research will further correlate sweat lactate levels with fitness, performance and blood lactate levels, Wang added.
AVOID THE BONK
If you exercise at high intensities for more than 90 minutes, you’ll need to fuel properly to avoid hitting the wall. How do you know if you’ve hit the wall? You’ll feel dizzy, disoriented, and suddenly heavy and uncoordinated. At this point, it’s best to stop and get some glucose (sugar) into your system. Gels and drinks (Gatorade, Powerade) are best as they take less energy to absorb compared to nutritional bars or bananas.
For more on fueling properly before/during/after a workout, check out Nancy Clark’s books on sports nutrition.