Concerns were expressed over orthostatic problems directly affecting the astronauts during and immediately following reentry.
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The BP-HR recorder was an extensively tested and used, commercially available, ambulatory unit. More information is provided in the hardware description below.
For preflight tests, the subject had a 30 minute briefing session on the recorder use and then made two recordings during simulations. For in-flight and postflight tests, 30 minutes was required for installation of the recorder; it was a one person effort, except for the wrapping of the arm cuff, which involved a second crewmember for less than one minute. The recorder was installed and started at least 30 minutes prior to strapping in for reentry. The recorder was carried on an elastic waist belt and did not interfere with other hardware. The recorder was worn through reentry without any restrictions on the crewmember. Inflation of the AGS was done as desired.
Ambulatory blood pressures (BP) and heart rates (HR) were recorded on a series of early Shuttle flights during preflight and pre-entry, entry, landing and egress. There were no significant differences between flight and preflight values during routine activity. Systolic blood pressure was slightly elevated in the deorbit period and systolic and diastolic blood pressure and heart rates were all elevated with onset of gravitoinertial loads and remained so through egress. Two of seven subjects had orthostatic problems in egress but their data did not show significant differences from others, except in heart rate. Comparison of this data to data from recent studies show even larger increase in HR/BP values during current deorbit and entry phases, which is consistent with increased heat and weight loads imposed by added survival gear. Both value and limitations of ambulatory heart rate/blood pressure data in this situation are demonstrated.