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Evidence of baroreflex adaptation to repetitive +Gz in fighter pilots.
Aviat Space Environ Med. 1998 May; 69(5):446-51.AS

Abstract

BACKGROUND

The arterial baroreflex acts to maintain arterial pressure in the face of an orthostatic challenge. The high +Gz loads experienced by fighter pilots represent an extreme form of orthostatic challenge. G-induced loss of consciousness (G-LOC) represents a failure of the baroreflex system to maintain the appropriate level of cerebral perfusion. The anecdotal experience of fighter pilots is that their cardiovascular systems adapt to frequent exposure to high +Gz levels.

HYPOTHESIS

The purpose of this study was to demonstrate that the baroreflex-mediated cardiovascular response of a group of 8 fighter pilots to a mild accelerative stimulus differs from that of a group of 12 non-pilots.

METHODS

Arterial pressures and heart rate responses to rapid head-up tilting to +75 degrees were compared between the two groups. Five variables were examined: systolic, diastolic, mean arterial and pulse pressures, and heart rate.

RESULTS

The cardiovascular responses of the groups were fundamentally different. In response to tilt, the non-pilots showed little change in systolic and mean arterial pressures, diastolic pressure increased slightly and pulse pressure decreased significantly. In the pilot group, however, significant increases were observed in systolic, diastolic and mean arterial pressures (p < 0.05), whereas pulse pressure did not change. Between groups there were significant differences observed in terms of arterial pressures (p < 0.05), but not heart rate.

CONCLUSION

The baroreflex of a fighter pilot is capable of adapting to +Gz, becoming a more sensitive and effective BP control system as a result. This adaptation affords the pilot greater protection against G-LOC.

Authors+Show Affiliations

Newman DG
302 Health Services Flight, RAAF Base Williamtown, NSW, Australia.
White SW
No affiliation info available
Callister R
No affiliation info available

MeSH

AdultAerospace MedicineAircraftBaroreflexGravitationHumansMalePostureUnconsciousness

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9591613

Citation

Newman, D G., et al. "Evidence of Baroreflex Adaptation to Repetitive +Gz in Fighter Pilots." Aviation, Space, and Environmental Medicine, vol. 69, no. 5, 1998, pp. 446-51.
Newman DG, White SW, Callister R. Evidence of baroreflex adaptation to repetitive +Gz in fighter pilots. Aviat Space Environ Med. 1998;69(5):446-51.
Newman, D. G., White, S. W., & Callister, R. (1998). Evidence of baroreflex adaptation to repetitive +Gz in fighter pilots. Aviation, Space, and Environmental Medicine, 69(5), 446-51.
Newman DG, White SW, Callister R. Evidence of Baroreflex Adaptation to Repetitive +Gz in Fighter Pilots. Aviat Space Environ Med. 1998;69(5):446-51. PubMed PMID: 9591613.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Evidence of baroreflex adaptation to repetitive +Gz in fighter pilots. AU - Newman,D G, AU - White,S W, AU - Callister,R, PY - 1998/5/20/pubmed PY - 1998/5/20/medline PY - 1998/5/20/entrez SP - 446 EP - 51 JF - Aviation, space, and environmental medicine JO - Aviat Space Environ Med VL - 69 IS - 5 N2 - BACKGROUND: The arterial baroreflex acts to maintain arterial pressure in the face of an orthostatic challenge. The high +Gz loads experienced by fighter pilots represent an extreme form of orthostatic challenge. G-induced loss of consciousness (G-LOC) represents a failure of the baroreflex system to maintain the appropriate level of cerebral perfusion. The anecdotal experience of fighter pilots is that their cardiovascular systems adapt to frequent exposure to high +Gz levels. HYPOTHESIS: The purpose of this study was to demonstrate that the baroreflex-mediated cardiovascular response of a group of 8 fighter pilots to a mild accelerative stimulus differs from that of a group of 12 non-pilots. METHODS: Arterial pressures and heart rate responses to rapid head-up tilting to +75 degrees were compared between the two groups. Five variables were examined: systolic, diastolic, mean arterial and pulse pressures, and heart rate. RESULTS: The cardiovascular responses of the groups were fundamentally different. In response to tilt, the non-pilots showed little change in systolic and mean arterial pressures, diastolic pressure increased slightly and pulse pressure decreased significantly. In the pilot group, however, significant increases were observed in systolic, diastolic and mean arterial pressures (p < 0.05), whereas pulse pressure did not change. Between groups there were significant differences observed in terms of arterial pressures (p < 0.05), but not heart rate. CONCLUSION: The baroreflex of a fighter pilot is capable of adapting to +Gz, becoming a more sensitive and effective BP control system as a result. This adaptation affords the pilot greater protection against G-LOC. SN - 0095-6562 UR - https://www.unboundmedicine.com/medline/citation/9591613/Evidence_of_baroreflex_adaptation_to_repetitive_+Gz_in_fighter_pilots_ DB - PRIME DP - Unbound Medicine ER -