title: The effects of head-out-of-water immersion on arterial wave reflection in healthy adults.
abstract: Swimming/hydrotherapy produces hemodynamic and physiological changes related to water immersion (WI). To evaluate the effects of head out (HO) WI on central hemodynamics, we prospectively studied 21 healthy subjects (62% male, age 37 +/- 13 years). Central aortic blood pressures (CA-BPs) and reflected wave properties were evaluated using applanation tonometry at baseline and upon 2 minutes of waist (W) and mid-chest (C) HOWI. Heart rate (HR) decreased from 83 +/- 15 to 73 +/-10 beats/min (P < .001). Brachial artery pulse pressure (PP) was unchanged (45 +/- 11 to 46 +/- 7 mm Hg; P = .20), CA-PP increased stepwise (27 +/- 7 to 32 +/- 8 to 33 +/- 6 mm Hg; P < .001). Reflected wave amplitude (P(s) - P(i)), and HR-corrected augmentation index (AI(a)@75) increased stepwise from baseline-W-C level HOWI [(P(s) - P(i)): 2 +/- 3 to 7 +/- 4 mm Hg, P < .001; AI(a)@75: 8 +/- 11 to 19 +/- 10%; P < .001]. HR-corrected ejection duration (ED(c)) and reflected wave systolic duration (Deltat(r)) increased progressively (ED(c): 389 +/- 23 to 408 +/- 25 to 435 +/- 13 milliseconds; P < .001; Deltat(r): 106 +/- 32 to 165 +/- 21 ms; P < .001). Indices of left ventricular (LV) workload including wasted LV energy subendocardial viability and tension time index increased upon HOWI. HOWI increases the amplitude and the duration of the reflected aortic pressure wave, increases wasted LV pressure energy, workload, and oxygen demand.
authors.affiliation: Division of Cardiovascular Medicine, State University of New York Downstate Medical, Center, Brooklyn, New York, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Lazar
authors.forename: Marsha
authors.initials: M
authors.lastname: Morris
authors.forename: Ghazanfar
authors.initials: G
authors.lastname: Qureshi
authors.forename: Gregory
authors.initials: G
authors.lastname: Jean-Noel
authors.forename: Wilmer
authors.initials: W
authors.lastname: Nichols
authors.forename: Mohammed Rehan
authors.initials: MR
authors.lastname: Qureshi
authors.forename: Louis
authors.initials: L
authors.lastname: Salciccioli