Live measurement includes heart rate, HRV, heart rate recovery, breathing rate, accelerometry, intensity & load and estimated core temperature – without pills or probes. Streaming live data allows real-time insight into the potential of heat stress, fatigue and dehydration. The system allows the coach to design practice drills and exercise regimes that will train each athlete, and the team as a whole, to their peaks, ensuring the highest level of performance per unit of effort.