Intraocular pressure during handgrip exercise: The effect of posture and hypercapnia in young males.

Autor: Mlinar T; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.; Jozef Stefan International Postgraduate School, Ljubljana, Slovenia., Jaki Mekjavic P; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.; Eye Hospital, University Medical Centre, Ljubljana, Slovenia.; Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia., Royal JT; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.; Jozef Stefan International Postgraduate School, Ljubljana, Slovenia., Valencic T; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia., Mekjavic IB; Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.; Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada.
Jazyk: angličtina
Zdroj: Physiological reports [Physiol Rep] 2021 Oct; Vol. 9 (20), pp. e15035.
DOI: 10.14814/phy2.15035
Abstrakt: Purpose: As part of our investigations of intraocular pressure (IOP) as a potential contributing factor to the spaceflight-associated neuro-ocular syndrome using the 6° head-down tilt (6°HDT) bed rest experimental model, we compared the effect of rest and isometric exercise in prone and supine 6°HDT positions on IOP with that observed in the seated position.
Methods: Ten male volunteers (age = 22.5 ± 3.1 yrs) participated in six interventions. All trials comprised a 10-min rest period, a 3-min isometric handgrip exercise at 30% of participant's maximum, and a 10-min recovery period. The trials were conducted under normocapnic (NCAP) or hypercapnic (F I CO 2  = 0.01; HCAP) conditions, the latter mimicking the ambient conditions on the International Space Station. IOP, systolic and diastolic pressures, and heart rate (HR) were measured during the trials.
Results: Isometric exercise-induced elevations in HR and mean arterial blood pressure. IOP in the prone 6°HDT position was significantly higher (p < 0.001) compared to IOP in supine 6°HDT position and seated trials at all time points. IOP increased with exercise only in a seated HCAP trial (p = 0.042). No difference was observed between trials in NCAP and HCAP. IOP in the prone 6°HDT position was constantly elevated above 21 mmHg, the lower limit for clinical ocular hypertension.
Conclusions: IOP in the prone 6°HDT position was similar to IOP reported in astronauts upon entering microgravity, potentially indicating that prone, rather than supine 6°HDT position might be a more suitable experimental analog for investigating the acute ocular changes that occur in microgravity.
(© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)
Databáze: MEDLINE
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