Coach,
I have been following all of the comments regarding the hypoxia issue.
Sure, Anoxia ( the complete absence of oxygen ) will cause organ and brain damage. After about six minutes, real damage is done, and that is nothing to laugh about. It is NOT permanent however. Rather it is a temporary condition that time and rehabilitation with cell regeneration will resolve, albeit months to do so. Recent studies have shown that the brain and all other organs DO regenerate.
Mountaineers routinely climb to altitude that have an oxygen saturation that is not
compatible with life lasting many days, yet they do it under heavy physical ( i.e.: oxygen demanding ) conditions. They do perform at reduced mental and physical capacities but only while in the oxygen deprived state with oxygen saturation in the 40-50% range ( normal 95-100%). I know this to be true as I have been involved with and climbed at high altitude as a climbing team physician over many years. During some of these high altitude climbs, we conducted research with the United States Navy Health Research Center, on the performance decrements that the climbers (me included) experienced.
Further more for shooters there is a small oxygen reserve in that the shooting athlete will balance the lungs at the level where the athlete is not forced to inhale or exhale and the lungs being balanced and yet having a small reserve for systems protections. This is the reserve the Doctor is referring to but the reports fail to include in the studies. In other words, the researcher has completed an incomplete report without consideration of or taking the balanced lung condition into account. Any increase in oxygenation has to come from some reserve as the vascular system does not have it available. This then puts the whole of the reports into question as to the validity of such information.
I have been in a hyperbaric chamber and directly experienced the effects of rapidly induced hypoxia for durations of up to 10 minutes. There were no immediate effects noted, only as the minutes ticked by did the effects on performance decline begin to develop as my original report indicated. Every thing is accumulated over time and reoccurrence of breath holding under the NRA shooting technique. For the our young shooters this is unacceptable.
I seriously doubt that any shooter can hold their breath for much more than 60 seconds ( yet I am sure a few can ), and I seriously doubt than any will hold their breath for that amount of time while shooting a one shot match but over time on a accumulative bases where the system is incorrectly flushed after each shot fired, it is very possible.
RESPONSE: THE SHOOTING ATHELTE WILL REPEATEDLY HOLD BREATH FOR EXTENDED TIMES AND THIS BECOME’s ACCUMLITIVE OVER TIME. Therefore, an athlete can ands will hold the breath longer then 60 seconds because no replenishment is accomplished in enough time to flush the system of bad gasses in the blood system.
Also, in
1966 American Heart Association, Inc. Cerebral Hemodynamics, Blood Gases, and Electrolytes during Breath-Holding and the Valsalva Maneuver JOHN S. MEYER M.D.1; FUMIO GOTOH M.D.1; YASUYUKI TAKAGI M.D.1; RYOJI KAKIMI M.D.
During the interval of tolerated breath-holding for 69 seconds or less, jugular venous oxygen tension was increased owing to increased cerebral blood flow resulting from an increase of arterial carbon dioxide tension.
This means that during breath holding of 69 seconds or less, the oxygen saturation of the blood in the brain actually INCREASES with breath holding.
RESPONSE: THIS IS VERY GOOD BUT YOU DID NOT SAY WHERE THIS OXYGEN RESERVE IS COMING FROM? “the oxygen saturation of the blood in the brain actually INCREASES with breath holding.” Sorry but I don’t think so. If this increase occurs then the subject is breathing and not holding the breath…
M. Holzschuh1 C. Woertgen1, C. Metz2 and A. Brawanski1
(1) Department of Neurosurgery, University of Regensburg, Regensburg, Germany
(2) Department of Anesthesiology, University of Regensburg, Regensburg, Germany
Summary The present study compares the change of cerebral blood flow and HbO2 ( Oxygen saturation of hemoglobin )measured by near-infrared spectroscopy (NIRS) after administration of 1000 mg acetazolamide intravenously. CBF ( Cerebral blood flow ) studies in 21 patients with ischaemic cerebrovascular disease were performed routinely with the133Xenon technique. Additionally the local HbO2 was recorded by NIRS. A rest study was followed by a second study after the administration of 1000 mg acetazolamide. In 18 patients we observed an increase of 30.8% of CBF and 4.7% of HbO2
So how can the shooter have all of the falsely claimed oxygen deprivation problems while holding the breath long enough to get a shot off ?
RESPONSE: MY POINT EXACTLY, under my findings I have the athlete fire within or less then one second. In such cases of firing in one second or less does not incur such problems where the current NRA Traditional Methods do.
There is also ample evidence to show that with the elevated Carbon dioxide levels in the brain (breath holding), the heart rate actually decreases, (benefit to a shooter, no and yes?) and the blood flow to the extremities (arms and legs) decreases (less pulse effect in the shooting position, no and yes?).
RESPONSE: EXACELY MY POINT IS IT NOT? Such actions in reduction are precisely what are directed with in the mental checklist and just for this reason. The check list used in the precise time limitations will safety protect the athlete from dangerous incidents during the one shot match on an accumulive basis.
There are actually benefits to intermittent hypoxia episodes as seen below.
J Appl Physiol. 2001 Apr;90(4):1431-40.
Intermittent hypoxia increases ventilation and Sa(O2) during hypoxic exercise and hypoxic chemosensitivity.
Katayama K, Sato Y, Morotome Y, Shima N, Ishida K, Mori S, Miyamura M.
Research Center of Health, Physical Fitness and Sports, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan.
The purpose of this study was 1) to test the hypothesis that ventilation and arterial oxygen saturation (Sa(O2)) during acute hypoxia may increase during intermittent hypoxia and remain elevated for a week without hypoxic exposure and 2) to clarify whether the changes in ventilation and Sa(O2) during hypoxic exercise are correlated with the change in hypoxic chemosensitivity. ...........1 wk of daily exposure to 1 hour of hypoxia significantly improved oxygenation in exercise during subsequent acute hypoxic exposures up to 1 wk after the conditioning, presumably caused by the enhanced hypoxic ventilatory chemosensitivity.
J Appl Physiol. 2001 Apr;90(4):1593-9. Review.
Invited review: Physiological and pathophysiological responses to intermittent hypoxia.
Neubauer JA.
Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, New Jersey 08903-0019, USA.
neubaeur@umdnj.edu
This mini-review summarizes the physiological adaptations to and pathophysiological consequences of intermittent hypoxia with special emphasis given to the pathophysiology associated with obstructive sleep apnea. Intermittent hypoxia is an effective stimulus for evoking the respiratory, cardiovascular, and metabolic adaptations normally associated with continuous chronic hypoxia. These adaptations are thought by some to be beneficial in that they may provide protection against disease as well as improve exercise performance in athletes.
Eur J Appl Physiol 2001 Apr;84(4):283-90
Training-induced increases in sea-level performance are enhanced by acute intermittent hypobaric hypoxia.
Meeuwsen T, Hendriksen IJ, Holewijn M.Research and Development Department, Netherlands Aeromedical Institute, Soesterberg, The Netherlands.
The goal of this study was to investigate to what extent intermittent exposure to altitude in a hypobaric chamber can improve performance at sea-level. Over a 10-day period, elite male triathletes trained for 2 h each day on a cycle ergometer placed in a hypobaric chamber. Training intensity was 60-70% of the heart rate reserve. Eight subjects trained at a simulated altitude of 2.500 m (hypoxia group), the other eight remained at sea-level (sea-level group). Baseline measurements were done on a cycle ergometer at sea-level, which included an incremental test until exhaustion and a Wingate Anaerobic Test. Nine days after training in hypoxia, significant increases were seen in all important parameters of the maximal aerobic as well as the anaerobic test. A significant increase of 7.0% was seen in the mean maximal oxygen uptake per kilogram body weight (VO2max), and the mean maximal power output per kilogram body weight (Wmax) increased significantly by 7.4%. The mean values of both mean power per kilogram body weight and peak power per kilogram body weight increased significantly by 5.0%, and the time-to-peak decreased significantly by 37.7%. In the sea-level group, no significant changes were seen in the abovementioned parameters of both the maximal aerobic and the maximal anaerobic test at the second post-test. The results of this study indicate that intermittent hypobaric training can improve both the aerobic and the anaerobic energy-supply systems.
The above articles do not generally address the practice of hyperventilating before breath holding episodes. This practice actually increases the oxygen saturation and keeps the saturation elevated for prolonged period of up to 2 1/2 minutes. In addition, most articles on hypoxia are studying the effect of prolonged oxygen deprivation, and not the brief episodes experience in shooting sports. Do NOT misunderstand me, Long term -many minutes to hours of hypoxia - can be devastating, and even deadly.
RESPONSE: Thank you for this admission of fact. And, validation of my responses to the occurrences of hypoxia among shooting athletes in training and competitions. The study findings would be of benefit if we all had hypobaric chambers to work with and during competitive training and competitions. Because of the high cost of hypobaric chambers, I am sure we will not see them in the ranges around the country.
I will not bore you with 100s of research articles that do NOT support the theories that have been espoused in this forum. You can find them yourself on MEDLINE researches.
RESPONSE: THANK YOU VERY MUCH FOR YOUR CONSIDERATION.
I have provided the above information to reassure all of you that holding your breath while getting the sight picture and the shot off, will NOT harm you if accomplished within the one second time limit, and may not even cause a reduction in shooting accuracy, and will actually improve shooting accuracy. I have NOT provided this information in any attempt to put down or "flame" anyone.
RESPONSE: But you have clearly tried to up hold the NRA point of view and protect the job security of the so call coach and training division of the NRA. However, you have also confirmed my postings for all to see. Sorry you tried so hard but fell flat with Maggie’s drawers. Better luck next time. You have the distinction of continued harm to our young shooter who are being taught the NRA and traditional trail and error method of shooting.
Chet Skinner, Coach and The Wizard of Target Talk.
Be well, shoot straight and often !
Dr. C. M. Bereznoff
Medical Director
Longmont Institute of Integrative Medicine
1304 N. Vivian St.
Longmont, Colorado, USA 80501-3217