What is the best way to recover?
Interesting point by Rippetoe on the CrossFit boards today:
"I'd like to see CFers stop laying down at the end of a workout like that. The highest incidence of arrythmias associated with exercise occur in this situation. It is far better to walk it off than it is to assume a position in which venous return to the heart is compromised at a terribly critical time by a cessation of contraction in the biggest muscles working in the exercise."
In response to Rippetoe, 'bingo' noted "I asked a cardiologist buddy for his take and he was rather adamant that arrhythmia risk is overwhemingly low and overwhelmingly outweighed by the risk of loss of conciousness from remaining upright."
I guess that's why everyone is always saying to "walk it off". This prompted some searching that led to a couple of interesting reads (linked below), which, of course, reveal that the body is a complex machine. Hmmm, hydrostatic column, hmmm, intrabdominal pressure from diaphragmatic descent, hmmm, maybe I should move my legs while laying down? Nah, I'll just lay down; if it mattered, I'd be cooked by now anyways.
Miller JD, Pegelow DF, Jacques AJ, Dempsey, JA.
Skeletal muscle pump versus respiratory muscle pump: modulation of venous return from the locomotor limb in humans. J Physiol. 2005 March 15; 563(Pt 3): 925–943.
Hogan MC, Grassi B, Samaja M, Stary CM, Gladden LB.
Effect of contraction frequency on the contractile and noncontractile phases of muscle venous blood flow. J Appl Physiol. 2003 Sep;95(3):1139-44.
2 comments:
And from Kilgore:
I’ve been asked to weigh in on this issue. We’re on a break from the CF Total meet we are having here in Wichita Falls today so here is a short perspective. If I miss anything or have misunderstood the root issues please let me know - it seems as there are two distinct considerations and issues: (1) It has been part of exercise lore for many many decades that if you exercise very hard then abruptly cease exercising and become motionless that you will increase the risk of syncope (passing out). Even without delving into the scientific literature there have been enough anecdotal reports of individuals having this occur that at least cursory caution is advised. When you are exercising hard the vascular pressures driving blood flow are quite high. With very hard aerobic exercise it blood pressure well into the 200’s (systolic) and when you are busting your butt with some big weights and big reps the pressure can rise into the 300’s. And that’s OK, those elevated pressures are perfectly normal and useful for our continued function. But if we immediately remove the load and stop moving, the cardiovascular system is immediately affected and venous return to the heart is reduced, in some individuals this can be manifested in a reduced cerebral blood flow and produces altered perceptions and conciousness (A blackout is another phenomenon entirely and is a loss of perception and consciousness not a change in perception or consciousness). My advice to all is to keep moving in order to keep the cardiovascular system slightly loaded in order to prevent precipitous drops in venous return. This will aid in being ready for the next set or round of a workout. The next safest thing to do specifically in regards to post effort loss of consciousness is, yes, lay down. I’d rather pass out when I’m lying down in order to avoid any injuries I might sustain from falling. And when you lay down the vascular column (how high the heart has to pump the blood to get to the brain) is reduced and this aids in maintaining consciousness. (2) Issue two is less well known amongst the general population and generally practicing physicians. If you have an individual who is suspected of having a cardiac arrhythmia you can generally force that arrhythmia to occur if you do a graded exercise test to maximal effort and then immediately place the individual in a supine position. The change in orthostatic pressures thus induced frequently will bring about the onset of the arrhythmia. This is a good thing since you would want to be able to produce the suspected arrhythmia within the controlled confines of the diagnostic laboratory. There is considerable research into orthostatic challenge, cardiac function, and exercise. In a healthy heart, the risk of injury that would result from lying down immediately after hard effort is fairly inconsequential. Rather the danger is with individuals with diseased cardiovascular systems. But how do you know which of your trainees has a healthy cardiovascular system? How do you know that yours is uncompromised? There are many examples of “aerobically fit” individuals dying of heart disease (Jim Fixx is the quintessential example along with cycling Ed Burke). I guess the bottom line is how much risk are you comfortable with assuming in balancing post-workout comfort and potential safety?
On the boards the next day:
Coach Rip, Dr. Kilgore, Kelly Starret, et al.
I spent a very enlightenting but ultimately fruitless couple of hours searching for research, or research that contained data on the specific question that we discussed ystd, whether or not abrupt cessation of intense exercise followd immediately by assuming a supine or prone position increases the risk of a dangerous cardiac arrythmia and therefore "sudden death." In short, no one has acquired and published data on subjects who have exercised through level V or into level VI looking at intra- or post-exercise arrhythmias.
So I went to my brother-in-law, Peter Spector, M.D. , associate professor of Medicine and Director of Electrophysiology at the University of Vermont for a hilarious, profanity-laced discussion of the issue. No matter what outcome or level of agreement we reach this was all worth it just to have that conversation. When told that the exercise physiology community and the fitness experts here at CF felt that MD's don't know anything about exercise Pete readily agreed, but also said that "exercise physiologists and fitness experts don't know what the &*%^ they're talking about in electrophysiology." So here's what he knows (I will paraphrase and clean up the language; Pete's not much of a "bookworm" either).
The healthy heart is able to take pretty much anything we can throw at it, Kelly's work-out included. It is able to recover without adverse effect whether one "walks out" the recovery or "flops" as Rip describes it. During vigorous exercise such as a stress test there are two distinct types of arrhytmias that arise. Arrythmia WITH exercise is generally ischemic (low oxygen), usually associated with coronary artery disease (Jim Fixx). Most cardiac arrythmias occur and exercise-related deaths occur DURING exercise.
There is, as Lon suggests, a well-established incidence of post-exercise arrythmias that occur within the first five minutes after exercise whether the subject is upright or supine. These are benign in the healthy heart but may be lethal in the rare instances where the heart has an abnormal electrical system. There is a relatively small number of cardiac abnormalities that predispose to arrhythmias such as Hypertrophic Cardiomyopathy (Hank Gathers, Reggie Lewis) and Long QT Syndrome. Of note here at CF is that Wolf-Parkinson-White Syndrome involves arrhthmias that are worse during exercise.
There is an autonomic shift that occurs with the cessation of exercise regardless of whether or not the athlete assumes a supine position or not. Pete, who arguably knows as much about electrophysiology as any human alive wants to know THIS might cause a lethal arrythmia because he cannot find a physiologic reason why it might, and in the lab the arrythmias are present whether or not a subject remains standing or flops. "They have to explain to me how it works before I'll say it makes sense to tell people to keep moving." To which I responded that the fitness experts would reply "You have to explain to us why it's not the stopping before we'll say it makes sense to prevent people flopping." He laughed and declared a stalemate.
So after all of this what are we left with (bingo talking now)? The vast majority of arrhythmias are ischemic and induced during exercise. Jim Fixx illustrates how difficult it is to know how healthy any individual athlete may or may not be and the ability to do 21 reps of back squats at 225# does not in and of itself mean that you are healthy in this context. Healthy hearts can handle pretty much anything we can throw at them, but unhealthy hearts are unpredictable and can throw a lethal arrhythmia in the exercise setting as demonstrated by Hank Gathers or after exercise a la Reggie Lewis. There is a well-described incidence of arrhythmias that occur within 5 minutes of exercise that are benign if you have a healthy heart and potentially lethal if you have one of several rare conditions. There is a change in the autonomic balance with the cessation of exercise (which Lon posits is greater if you flop); there is no proof or electrophysiologic reason that the post-exercise arrythmias are due to this change or to flopping; there are reports of athletes dying after flopping after an intense CF-type work-out.
The electrophysiologist says that without providing an explaination of HOW these are related it makes no sense to create a hard recommendation. The Crossfit trainers and exercise physiologists say that without proof that it ISN'T the flop that causes the event it makes no sense not to recommend against flopping. Appropriate data does not exist to allow us to solve this stalemate. In the absence of science, thinking about liability, it would be unwise for Crossfit the organization to adapt a firm policy on this issue. In the end it is up to the individual trainer/affiliate/athlete to decide what suggestion to make or course of action to take after "Helen", and Lon's suggestion regarding "comfort vs. risk" is as good as any.
D.
Comment #44 - Posted by bingo at September 2, 2007 08:45 AM
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