Prolonged telemetric monitoring of heart rate variability using wireless intelligent sensors and a mobile gateway

Mobile health monitors allow patients to leave the hospital and engage in normal activity, uploading physiological data only periodically. Most existing systems use fixed gateways to upload data to the server. The Wireless Distributed Data Acquisition System presented in this paper is developed for prolonged, synchronized, health/stress monitoring of a selected group of subjects/patients. The system is based on mobile client devices, and mobile gateways. We use personal digital assistant (PDA) as a mobile gateway to collect data from individual monitors, and synchronize collected records with existing records on the telemedical server. Each client device uses flash memory as a temporary storage until the reliable connection with a mobile gateway is established. Individual intelligent sensors are based on a very low-power microcontroller TI MSP430F149, and use standard 900 MHz wireless link, and flash memory. This system is used to evaluate the effects of stressful military training. We have found that patterns of heart rate variability correlate with stress tolerance.