Valsalva maneuver

In Mark Rippetoe's Starting Strength: Second Edition he advocates the use of the Valsalva maneuver.  He makes the following points:

- The likelihood of a cerebrovascular accident is overplayed in regard to the Valsalva maneuver

- The likelihood of an orthopedic injury is greatly downplayed in regard to the Valsalva maneuver

- The pressure applied by the Valsalva maneuver is a natural response to heavy exertion, as the opposing forces being applied to the cerebrospinal fluid and the cardiovascular system in the trunk are in balance.

- The process of inhalation increases pressure in your thoracic cavity, which provides support to the surrounding abdominals, obliques and spinal erectors.

- The Valsalva maneuver is used by fighter pilots to keep blood in the brain in momentary high-G conditions to prevent a blackout.

- The cardiovascular system adapts to resistance training just like all the other tissues and systems in the body.

- It is a good practice to take and hold the biggest breath you can before every heavy rep.


However, do the positive effects (increased stability for maximum force production and decreased risk of an orthopedic injury) outweigh the possible negative implications of syncope, stroke, blown aneurysm or in very extreme cases death enough to use it during weight training?


This book: [URL="http://books.google.com/books?id=btesVutdJ2EC&pg=PA274&lpg=PA274&dq=exercise+physiology+valsalva&source=web&ots=XrXUuiOrCz&sig=bnxxMB1GDiI-ruTMpPNHzr_L74k&hl=en#PPA275,M1"]http://books.google.com/books?id=btesVutdJ2EC&pg=PA274&lpg=PA274&dq=exercise+physiology+valsalva&source=web&ots=XrXUuiOrCz&sig=bnxxMB1GDiI-ruTMpPNHzr_L74k&hl=en#PPA275,M1[/URL]
whether or not a legitimate source (although it appears to be as it is a textbook; however, textbooks have been wrong), says that a prolonged Valsalva maneuver actually produces an acute drop in blood pressure.  Also stated is that resistance exercise rises blood pressure (273).

   It says that the confusion regarding the matter arises because a Valsalva held for too short a period of time usually accompanies the straining found in resistance training (274).  That sounds as if the Valsalva maneuver is realatively safe in that regard, although I would like to find a few more legitimate and educated sources on the matter.

    The other thing to consider is blood circulation and oxygen deprivation.  According to that source, a prolonged Valsalva maneuver during a static exercise that involves straining lowers the heart rate, and thus reducing venous return and blood pressure.  The negative side effects of this lowered heart rate diminish blood supply to the brain, which can produce dizziness, "spots before the eyes" (same thing as stars?), or snycope (otherwise known as passing out) (274).  I have heard that many older people die because they are straining on the toilet or otherwise.  I guess those are conditions in which they are not in good health in the first place though.  I have definitely had a headache after heavy deadlifts before and have most definitely seen stars after a set of squats.  Were those occurrences a result of the Valsalva?

    It would be nice if the book told the reader how long a prolonged Valsalva maneuver is.  It could be a couple seconds, or a minute, but we do not know because the only description is "prolonged".  Since the Valsalva maneuver involves holding ones breath, doesn't that restrict oxygen flow to the brain and muscles (which would be counterproductive)?  I assume that a Valsalva of sufficient length to cause lightheadedness, syncope or poor oxygen circulation to the brain and muscles is being performed for way too long, longer than one would use the maneuver for a rep.

What are your thoughts guys?

RE: Starting Strength Second Edition form questions - Page 2 ...He clearly stated that he gets light headed and valsalva for higher reps does not work .... So I should inhale as I am going down, then Valsalva going up, ...
www.discussbodybuilding.com/m_353371/mpage_2/tm.htm

For our full discussion of the topic...go here:
http://www.discussbodybuilding.com/tm.aspx?m=359015

My Journal - www.discussbodybuilding.com/fb.ashx?m=168123
PRIMERS:
Gain Muscle - www.discussbodybuilding.com/fb.ashx?m=111173
Lose Fat - www.discussbodybuilding.com/fb.ashx?m=111175