Sweat

Over the last years continuous and non-invasive measurement techniques to gain insight in health and performance have become popular. These continuous and non-invasive biochemical measurement techniques are commonly manifested in wearable sensors for which sweat is the most preferred bodily fluid to use due to its easy and continuous accessibility and rich biomarker content. Currently sweat sensor developments are largely technology driven while the scientific foundations for the monitoring of health and performance via sweat often are lacking. In the current thesis we aimed to contribute to knowledge on how sweat composition is affected and how to measure sweat in a reliable way. Direct relations between blood and sweat are often assumed. For many components in blood it has already been established how their concentrations relate to specific diseases or sports performance. We have shown that during submaximal exercise relations between blood and sweat sodium, chloride, potassium, lactate, ammonia and glucose were non-significant. Therefore, it may be more relevant to establish what information is in sweat itself and how it varies within individuals. Subsequently, we observed that sweat becomes less salty during heat acclimation. In this way, sweat composition could provide information about the physical state of the body (in this case heat acclimation). By obtaining such knowledge, we hope that athletes and/or healthcare could be eventually be provided with meaningful feedback about physiological parameters based on sweat