HOME >> BIOLOGY >> NEWS
Deciphering the limits to human maximal exercise performance

It has remained unknown during centuries what is the main factor limiting maximal exercise capacity in humans. During the past century evidence has accumulated suggesting that maximal exercise capacity in humans is limited by the maximal amount of O2 that can be delivered to the active muscles.

A rather important step in this direction was the finding that blood flow may reach maximal values around 2-4 l kg-1 min-1 in the quadriceps muscle during maximal knee extension exercise. Since the mean muscle mass of the quadriceps muscle is about 2.5 kg, it was suggested that this magnitude of perfusion would overwhelm the pumping capacity of the heart (which lies close to 25 l.min-1 in normal young humans) if a similar level of hyperaemia could be elicited during whole body exercise in the majority of active muscles.

By studying elite athletic humans with highly trained arm and legs muscles (cross-country skiers), Dr Jose A. Calbet and a team of Scandinavian colleagues led by Professor Bengt Saltin present, in the forthcoming issue of The Journal of Physiology, conclusive evidence showing that during maximal exercise in the upright position the combined maximal arm and leg blood flows surpass the maximal pumping capacity of the heart.

The latter means that to avoid hypotension during maximal exercise in the upright position, humans must restrain the voracity for blood flow of active muscles. This finding may facilitate the comprehension of several pathologic conditions characterised by reduced exercise tolerance and may guide some new therapeutic approaches.


'"/>

Contact: Kate Stinchcombe
kate.stinchcombe@oxon.blackwellpublishing.com
Blackwell Publishing Ltd.
10-Jun-2004


Page: 1

Related biology news :

1. Deciphering how arteries contribute to hypertension
2. Deciphering the genetic basis of the mosquitos senses
3. Discovery of tiny microbes in ancient Greenland glacier may define limits for life on Earth
4. New approach limits damage after heart attack and improves survival, say Scripps Research scientists
5. Inherent mistrust of research institutions limits minority representation
6. Pleasure boat speed limits can stir up trouble in shallow lakes
7. Vaccination following spinal cord injury: Innovative Weizmann Institute approach limits paralysis
8. Scientists decipher "fail-safe" system that limits gene copying in cells
9. Soil fertility limits forests capacity to absorb excess CO2.
10. Climate change plus human pressure caused large mammal extinctions in late Pleistocene
11. Lycopene slows human prostate tumour growth in mice and combined with vitamin E is even better

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:4/11/2017)... NXT-ID, Inc. (NASDAQ:   NXTD ) ("NXT-ID" or ... independent Directors Mr. Robin D. Richards and Mr. ... the company,s corporate governance and expertise. ... Gino Pereira , Chief Executive Officer said," ... and benefiting from their considerable expertise as we move forward ...
(Date:4/5/2017)... 2017  The Allen Institute for Cell Science today ... one-of-a-kind portal and dynamic digital window into the human ... first application of deep learning to create predictive models ... and a growing suite of powerful tools. The Allen ... future publicly available resources created and shared by the ...
(Date:4/5/2017)... -- KEY FINDINGS The global market for ... of 25.76% during the forecast period of 2017-2025. The ... the growth of the stem cell market. ... INSIGHTS The global stem cell market is segmented on ... stem cell market of the product is segmented into ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... , ... October 11, 2017 , ... ComplianceOnline’s Medical Device ... on 7th and 8th June 2018 in San Francisco, CA. The Summit brings together ... as several distinguished CEOs, board directors and government officials from around the world to ...
(Date:10/11/2017)... ... October 11, 2017 , ... ... implantation and pregnancy rates in frozen and fresh in vitro fertilization (IVF) ... and maternal age to IVF success. , After comparing the results from the ...
(Date:10/10/2017)... ... October 10, 2017 , ... Dr. Bob Harman, founder and CEO ... Diego Rotary Club. The event entitled “Stem Cells and Their Regenerative ... attendees. Dr. Harman, DVM, MPVM was joined by two human doctors: Peter B. ...
(Date:10/9/2017)... 9, 2017  BioTech Holdings announced today identification ... its ProCell stem cell therapy prevents limb loss ... Company, demonstrated that treatment with ProCell resulted in ... as compared to standard bone marrow stem cell ... in reduction of therapeutic effect.  ...
Breaking Biology Technology:
Cached News: