title: Physiological monitoring and analysis of a manned stratospheric balloon test program.
abstract: BACKGROUND
  The Red Bull Stratos Project consisted of incremental high altitude parachute jumps [maximum altitude 127,852 ft (38,969 m)] from a pressurized capsule suspended from a stratospheric helium-filled balloon. A physiological monitoring system was worn by the parachutist to provide operational medical and acceleration data and to record a unique set of data in a supersonic environment.
  
  
  METHODS
  Various physiological parameters, including heart rate (HR), respiratory rate (RR), skin temperature, and triaxial acceleration, were collected during the ascent, high altitude float, free fall, and parachute opening and descent stages of multiple low- and high altitude jumps. Physiologic data were synchronized with global positioning system (GPS) and audiovisual data for a comprehensive understanding of the environmental stressors experienced.
  
  
  RESULTS
  HR reached maximum during capsule egress and remained elevated throughout free fall and landing. RR reached its maximum during free fall. Temperature data were unreliable and did not provide useful results. The highest accelerations parameters were recorded during parachute opening and during landing. During each high altitude jump, immediately after capsule egress, the parachutist experienced a few seconds of microgravity during which some instability occurred. Control was regained as the parachutist entered denser atmosphere.
  
  
  CONCLUSIONS
  The high altitude environment resulted in extremely high vertical speeds due to little air resistance in comparison to lower altitude jumps with similar equipment. The risk for tumbling was highest at initial step-off. Physiological responses included elevated HR and RR throughout critical phases of free fall. The monitoring unit performed well despite the austere environment and extreme human performance activities.
authors.affiliation: Department of Medicine, Section of Emergency Medicine and Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030-1402, USA.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Garbino
authors.affiliation: Department of Medicine, Section of Emergency Medicine and Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030-1402, USA.
authors.forename: Rebecca S
authors.initials: RS
authors.lastname: Blue
authors.affiliation: Department of Medicine, Section of Emergency Medicine and Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030-1402, USA.
authors.forename: James M
authors.initials: JM
authors.lastname: Pattarini
authors.affiliation: Department of Medicine, Section of Emergency Medicine and Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030-1402, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Law
authors.affiliation: Department of Medicine, Section of Emergency Medicine and Center for Space Medicine, Baylor College of Medicine, Houston, TX, 77030-1402, USA.
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Clark
mesh_terms: D000054:Acceleration; D000337:Aerospace Medicine / Q000295:instrumentation*; D000401:Aircraft; D000531:Altitude; D006339:Heart Rate; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D056152:Respiratory Rate