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Oxygen delivery challenges of maxima...

Kellawan, Jeremy Mikhail.

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Oxygen delivery challenges of maximal exercise and initial orthostatic hypotension.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Oxygen delivery challenges of maximal exercise and initial orthostatic hypotension./
作者:	Kellawan, Jeremy Mikhail.
面頁冊數:	211 p.
附註:	Source: Dissertation Abstracts International, Volume: 75-07(E), Section: B.
Contained By:	Dissertation Abstracts International75-07B(E).
標題:	Biology, Physiology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NS27931
ISBN:	9780499279316

Oxygen delivery challenges of maximal exercise and initial orthostatic hypotension.
Kellawan, Jeremy Mikhail.

Oxygen delivery challenges of maximal exercise and initial orthostatic hypotension. - 211 p.

Source: Dissertation Abstracts International, Volume: 75-07(E), Section: B.

Thesis (Ph.D.)--Queen's University (Canada), 2013.

The ability to exercise for more than a short period requires energy to be supplied by using oxygen (aerobic energy supply). How quickly we can supply energy depends on how much oxygen we can deliver to muscles. Similarly, delivery of oxygen (O2 del) to the brain is important as brief, transient disruptions can cause nausea or fainting. Therefore, regulation of O2 del so that the O2 supply matches the metabolic requirement (O2 del matching metabolic demand) is essential to exercise tolerance and brain function. O2 del to the brain is often researched in response to orthostatic stress, however little is known about vascular responses protecting O2 del. In muscle, use of a forearm exercise model is common as measuring O2 del is difficult in other exercise modalities. Unfortunately, it is also difficult to measure/test metabolism in the forearm. Hence, measuring O2 del response to exercise at a known metabolic intensity is difficult. Purpose: To investigate O2 del matching metabolic demand in the following manner: 1) develop a repeatable and reliable critical power (CP, highest sustainable rate of aerobic metabolism) test for the forearm exercise model 2) discover if individual differences in O2 del account for differences in forearm CP (fCP) 3) determine if fCP is sensitive to changes in O2 del 4) characterize cerebral vascular response to an orthostatic challenge. Methods: Echo and Doppler ultrasound measured blood flow through the brachial artery. Venous blood samples were used to measure hemoglobin and O2 content for calculations of O2 del and consumption. Middle cerebral blood velocity measured via transcranial Doppler ultrasound. Blood pressure was measured using finger photoplethysmography. Results: 1) fCP can be accurately estimated from a maximal effort handgripping test 2) Inter-individual differences in O2 del account for most of the variance in fCP 3) fCP is sensitive to changes in O2 del 4) cerebral vascular responses blunt cerebral hypoperfusion in response to initial orthostatic hypotension. Conclusions: CP is an exercise characteristic of aerobic metabolism which is dependent on and sensitive to O2 del. Therefore, fCP can be used in the forearm exercise model to research O2 del-metabolism matching.

ISBN: 9780499279316Subjects--Topical Terms:

1017816
Biology, Physiology.

Oxygen delivery challenges of maximal exercise and initial orthostatic hypotension.
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502 $a Thesis (Ph.D.)--Queen's University (Canada), 2013.
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