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Influence of a Negative Hydrostatic Column and Central Fluid Shift via ‐6° Head‐down Tilt Posture on Cardiovascular Performance
Author(s) -
Ade Carl J,
Harms Craig A,
Musch Tim I,
Barstow Tomas J
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.1035.1
Subject(s) - supine position , head down tilt , medicine , beat (acoustics) , cardiology , endocrinology , blood pressure , physics , acoustics
Aims To examine the influence of a negative hydrostatic column via ‐6° head‐down tilt (HDT) exercise on cardiovascular performance and to determine if the HDT posture stimulates greater cardiovascular adaptations during exercise training compared to upright (UPR). Methods 9 males (21±2 yrs) performed VO 2peak cycle exercise tests in the UPR, supine (SUP), and HDT positions. 9 different males (20±2 yrs) were endurance trained on a cycle ergometer in the UPR position for 8 wks (UPR TN ) or in the UPR position for 4 wks followed by 4 wks in the HDT position (HDT TN ). Results During acute exercise, VO 2peak was decreased in the SUP and HDT positions compared to the UPR (2.01±0.46, 2.01±0.51 vs. 2.32±0.61 L/min respectively, P < 0.05). Stroke volume (SV) at 100 watts was greater in the HDT position compared to the UPR (77±5 vs 71±4 ml/beat, P < 0.05). Following training SV at 100 watts increased from 77±1 to 85±9 ml/beat in the HDT TN group during UPR exercise (P < 0.05). In addition, SV increased from 76±10 to 85±16 ml/beat in the HDT position for the same individuals (P < 0.05). SV in the UPR TN during 100 watts in the HDT position was unchanged but increased during UPR exercise following 8wks of training (65±3 to 75±5 ml/beat, P = 0.21). Conclusions HDT exercise increases sub‐maximal SV compared to UPR exercise. Training in the HDT position induces cardiovascular adaptations in both UPR and HDT exercise that are not achieved with UPR training.