Dehydration and Performance

[Guest guest]

I am trying to find studies that link dehydration with performance, especially

mental performance (eg. concentration etc). Most of the studies I have found

refer to the link between dehydration and a decrease in performance without

referencing it.

Noakes (The Lore of Running, 2001, 4th Ed) points out most of the top marathon

runners often finish their races as the “hottest and most dehydrated”. He also

traces the guidelines of the ACSM for fluid intake and shows that they are NOT

evidence based.

My main question is to find out exactly how the researchers managed to attribute

dehydration as the dominant factor in a decrease in mental performance, but am

open to discuss other matters of dehydration if you are interested.

Regards,

Grant

Strength and Rehabilitation Consultant

B.Sc. (Hons) Ex. Sci.

M.A.A.E.S.S., M.A.S.C.A.

PHYSIOKINETICS

Gold Coast, Australia

(+61) 409 625 263

--

___________________________________________________________

Sign-up for Ads Free at Mail.com

http://promo.mail.com/adsfreejump.htm

[Guest guest]

Hi Grant!

The book " Exertional Heat Ilnesses, " by Dr. Larry Armstrong contains the

information for which you are searching. It is available from

Human Kinetics <www.HumanKinetics.com>

Best wishes!

Dan Wathen,

Youngstown (OH) State University

In Supertraining , " Grant " <physiokinetics@m...> wrote:

> I am trying to find studies that link dehydration with performance, especially

mental performance (eg. concentration etc). Most of the

studies I have found refer to the link between dehydration and a decrease in

performance without referencing it.

>

> Noakes (The Lore of Running, 2001, 4th Ed) points out most of the top marathon

runners often finish their races as the " hottest and

most dehydrated " . He also traces the guidelines of the ACSM for fluid intake and

shows that they are NOT evidence based.

>

> My main question is to find out exactly how the researchers managed to

attribute dehydration as the dominant factor in a decrease

in mental performance, but am open to discuss other matters of dehydration if

you are interested.

>

>

> Regards,

>

> Grant

> Strength and Rehabilitation Consultant

> B.Sc. (Hons) Ex. Sci.

> M.A.A.E.S.S., M.A.S.C.A.

>

> PHYSIOKINETICS

> Gold Coast, Australia

> (+61) 409 625 263

[Guest guest]

<<<I am trying to find studies that link dehydration with

performance, especially mental performance (eg. concentration etc).

Most of the studies I have found refer to the link between

dehydration and a decrease in performance without referencing it.

Noakes (The Lore of Running, 2001, 4th Ed) points out most of the top

marathon runners often finish their races as the " hottest and most

dehydrated " . He also traces the guidelines of the ACSM for fluid

intake and shows that they are NOT evidence based.

My main question is to find out exactly how the researchers managed

to attribute dehydration as the dominant factor in a decrease in

mental performance, but am open to discuss other matters of

dehydration if you are interested.>>>

***When I was at university one of my friends did some excellent

research into dehydration and brain volume (brain scans using the

MRI). I emailed her and here is the reply:

" Basically what we found was that up until approx 2.5% loss in body

mass, the fluid in your brain decreases and therefore your brain has

more space to move around in your skull and therefore increases the

chance of injury. At approx 2.5% there appears to be a bulk flow of

fluid into the brain (some kind of protective mechanism) however,

this then could cause excess fluid and then the fluid can damage the

brain tissue if there is impact against the skull. The brain is

protected by fluid which is constantly produced in the brain and we

think that when you become dehydrated, the brain reacts and produces

more fluid. "

Hope that may be of some interest

Carruthers

Wakefield, UK

[Guest guest]

<<<I am trying to find studies that link dehydration with

performance, especially mental performance (eg. concentration etc).

Most of the studies I have found refer to the link between

dehydration and a decrease in performance without referencing it.

Noakes (The Lore of Running, 2001, 4th Ed) points out most of the top

marathon runners often finish their races as the " hottest and most

dehydrated " . He also traces the guidelines of the ACSM for fluid

intake and shows that they are NOT evidence based.

My main question is to find out exactly how the researchers managed

to attribute dehydration as the dominant factor in a decrease in

mental performance, but am open to discuss other matters of

dehydration if you are interested.>>>

***I found the following in my files:

% Weight Loss Effects of Water / Weight Loss

1% Threshold of thirst & impaired exercise performance

2% Stronger thirst, vague discomfort & sense of oppression

3% Dry mouth, increasing heamoconcentrations decrease urine output

4% Decrement of 20-30% in work capacity

5% Poor concentration, headache, impatience, sleepiness

6% Severely impaired temperature regulation, increased respiratory

rate leading to tingling & numbness in extremities

7% Likely collapse

It is taken from Greenleaf (1992) (Medicine and Science in Sports and

Exercise Science). It may be worth trying to obtain a copy of the

article?

Carruthers

Wakefield, UK