Cardiovascular response to lower body negative pressure before, during, and after ten days head-down tilt bedrest
- PMID: 1509893
Cardiovascular response to lower body negative pressure before, during, and after ten days head-down tilt bedrest
Abstract
The haemodynamic response to lower body negative pressure (LBNP) was studied in 6 test subjects before (baseline), during, and after (recovery) ten days of 6 degrees head-down bedrest. The LBNP protocol consisted of a 35 min control period, application of a staircase differential pressure profile (15 min at -15 mmHg; 5 min at -30 mmHg; 15 min at -40 mmHg), and a 10 min post-stress observation period. Cardiac output was measured by a foreign gas rebreathing technique. Finger plethysmographic arterial blood pressure (BP), ECG, and heart rate (HR), lower limb crossectional area, and the electrical impedance of three body segments were recorded continuously. As expected, HDT caused a decrease in plasma volume and total body fluid volume. Resting CO at the end of HDT was 16% below the baseline level and similar to CO in the upright position before HDT. Stroke volume (SV) was also reduced, but there were no significant changes in control HR or BP. Absolute changes in CO and SV during LBNP were similar at baseline and during HDT, but the relative changes were larger during HDT. HR and vasoconstriction responses were enhanced, but presyncope occurred in two subjects. Reduced cardiac filling with decreased stroke volume at rest is the apparent primary cause of the altered LBNP response during HDT.
Similar articles
-
Effect of lower body negative pressure on orthostatic tolerance and cardiac function during 21 days head-down tilt bed rest.J Gravit Physiol. 2003 Dec;10(2):11-7. J Gravit Physiol. 2003. PMID: 15838970
-
[Effects of lower body negative pressure in the first and last week during 21 d head-down bed rest on orthostatic tolerance and cardiac function].Space Med Med Eng (Beijing). 2002 Apr;15(2):84-8. Space Med Med Eng (Beijing). 2002. PMID: 12066823 Chinese.
-
Effect of lower body negative pressure against orthostatic intolerance induced by 21 days head-down tilt bed rest.Aviat Space Environ Med. 2002 Apr;73(4):335-40. Aviat Space Environ Med. 2002. PMID: 11952053 Clinical Trial.
-
[Effect of lower body negative pressure and rotating-table simulated push-pull effect in flight on cardiovascular function].Space Med Med Eng (Beijing). 2001 Dec;14(6):400-4. Space Med Med Eng (Beijing). 2001. PMID: 11887892 Clinical Trial. Chinese.
-
Cardiovascular and hormonal response during a 4-week head-down tilt with and without exercise and LBNP countermeasures.J Gravit Physiol. 1996 Apr;3(1):37-48. J Gravit Physiol. 1996. PMID: 11539306
Cited by
-
New horizons in the ageing autonomic nervous system: orthostatic hypotension and supine hypertension.Age Ageing. 2022 Aug 2;51(8):afac150. doi: 10.1093/ageing/afac150. Age Ageing. 2022. PMID: 35930723 Free PMC article.
-
Introducing the Concept of Exercise Holidays for Human Spaceflight - What Can We Learn From the Recovery of Bed Rest Passive Control Groups.Front Physiol. 2022 Jul 4;13:898430. doi: 10.3389/fphys.2022.898430. eCollection 2022. Front Physiol. 2022. PMID: 35874509 Free PMC article.
-
Long COVID and neuropsychiatric manifestations (Review).Exp Ther Med. 2022 May;23(5):363. doi: 10.3892/etm.2022.11290. Epub 2022 Apr 1. Exp Ther Med. 2022. PMID: 35493431 Free PMC article. Review.
-
How COVID-19 can cause autonomic dysfunctions and postural orthostatic syndrome? A Review of mechanisms and evidence.Neurol Clin Neurosci. 2021 Nov;9(6):434-442. doi: 10.1111/ncn3.12548. Epub 2021 Oct 26. Neurol Clin Neurosci. 2021. PMID: 34909198 Free PMC article. Review.
-
Orthostatic hypotension in older people: considerations, diagnosis and management.Clin Med (Lond). 2021 May;21(3):e275-e282. doi: 10.7861/clinmed.2020-1044. Clin Med (Lond). 2021. PMID: 34001585 Free PMC article. Review.
MeSH terms
LinkOut - more resources
Medical
Research Materials