Only 5 % of all wearables have been scientifically validated, most of them are just gadgets. Progress however is made in accuracy of wearables and mainly in algorithms to distill relevant information from objective measured data. The method that we promote is based upon longer existing scientific insight bringing the method of metabolic energy use versus recovery for analyzing mental problems. Today it becomes possible to measure physiological variables rather than using questionnaires. The new part is to use continuous measurements of physiological variables in combination with real-time estimation of the individual metabolic energy balance. The algorithms used adapt to the individual, are self-adapting to time-varying characteristics of the same user, are running in real-time and work in on people while in full activity. The first health issue we focus on is an objective measure for use and recover of metabolic energy for mental load due to cognitive load or mental stressors. We give examples and demonstrate how accurate the technology is by showing the real-time measured mental focus zone of a race driver. The second issue is automated infection monitoring.