Doc’s Talk 04-07-2013

Teleology is the science that states everything you have is there for a reason, via evolution, or other factors.  E.g.  Feet are for running and not for much else.  Eyes are meant to see, ears are meant to hear.  If someone hits you in the ear you don’t see sharp lights, you hear noise and have pain.  If someone pokes you in the eye, you see lights, you don’t hear sounds, and you feel pain.

A teleological question:
Why do our eyes point straight ahead?  Think about it, next week Dr. Scaff will give you the answer. Believe it or not, this all relates to running in the long run.

Dr. Scaff talked about heat, how it benefits us, how it hurts us.

Last Sunday Dr. Scaff discussed how to calculate maximum heart rate (200 minus half your age), that when you are at 75% of your maximum heart rate you begin to go anaerobic and burn up oxygen faster than you are taking it in, and that nobody can run a marathon sprinting.

He talked about the Talk Test:  The rule is never run so fast you can’t talk, and you never run so slow that you can sing.  This validates itself and will work at altitude and everywhere else.  As long as you can talk you’re aerobic, when you can’t you’re anaerobic.

In previous weeks, Dr. Scaff likened your body to an engine or a car:  You have a motor, a carburetor, a distribution system, fuel, and of course the byproduct or work is always heat.  You cannot work without heat, and just like a car can overheat, you can overheat.

At rest your temperature is somewhere between 98°F and 99.4°F, it varies a little bit in people.  As we start exercising, our core temperature starts to go up (the only way to take a good core temperature is a rectal thermometer), and after about an hour your temperature is between 100°F and 101°FThat is the optimal temperature for exercise.  Just like a car, the fluids and oils in your knees and joints are stiff when they are cold; with heat they lubricate better.  The enzymes for energy metabolism work better when your body is at 100°F, that is why you feel sort of loughy in the morning, you are not only stiff, but the enzymes are not prepared to convert fat to energy or carbohydrate to energy.  So we want our temperature to be about 101°F.  Even before we knew this people would say, “I’ve got to warm up.”  That’s true, you do have to warm up.

However, the byproduct of work is further heat and as temperature starts to increase you start to get into problems.  When the temperature reaches 104°F, heat stroke can occur.  Heat stroke, untreated can be 90% fatal. That is why if you fall down in the marathon, before they even look at you they are going to throw ice on you.  It is the coldest experience you can have, but they will start rapid body cooling because it works.  If you collapse with heat stroke, since you are no longer running, or promoting any air exchange whatsoever, temperature starts to go up and cascades.  When your temperature gets to about 107° it is fatal.

Long distance running is one of the few sports where we can train you to run through the signs, i.e. we can train you to kill yourself.  You take a person who has not trained, they go run, they get so tired they fall down or they puke, and they are ok, …but we can train to over train, and get into problems.

What is even worse, if you measure the temperature in the liver, it can be as much as 2 degrees higher.  That means that the liver is thoroughly stressed.  What is the commonest cause of acute liver poisoning, acute liver failure in the U.S.?  Everybody says alcohol (we’re Victorians).  No.  It is Tylenol (acetaminophen).  If you read on the black box warning on Tylenol it says to be careful using that product.  If you have a kid with a high fever the liver is even more sensitive.  If you give them some Tylenol you fry the liver and that’s the end of it.

Hearing this a pediatrician asked Dr. Scaff, “What do I do?”  Dr. Scaff says he is not a pediatrician, and does not know, but thinks he would rather throw the child in an alcohol bath and get their temperature down, than give them very much Tylenol.  So he does not have the answer for that particular issue.  He does, however, discourage people from taking acetaminophen routinely.

After you have run an hour or 2 your temperature is 100°F – 101°F, and then you stop and start drinking beverages and your temperature slowly decays back to normal over 5 or 6 hours.  During that time, your basal metabolic rate is higher, you are burning more calories, you have burned off the exogenous calories that you ate the night before, so you are burning your own fat.  It is a wonderful, wonderful situation to be in as long as it is not too good a situation.  You don’t want to be at either end, you don’t want to be running with a temperature of 99°F and you don’t want to be running with a temperature of 104°F.

Temperature starts to increase as you excessively sweat.  When you have lost about 5 – 10% of your body weight, core temperature starts to increase, there is just not enough fluid in the veins and arteries to dissipate heat.  So just figure out what 5% of your body weight is (5 lbs if you are 100 lbs, 7.5 lbs if you are 150 lbs).  If you’ve lost more than that you are losing too much.

A gallon of water weighs 8.35 lbs.  If you look at how much you have to take, you realize that’s a lot of water!  And that is just to replace your daily loss.  When you get up in the morning, you are usually 1 or 2 lbs lighter than you went to bed at night – that is insensible water loss, through the skin, vaporization through your exhaled breaths, your lungs, etc.

So water balance is extremely important.  And although it is said that you should not drink until you get thirsty, that is a fatal approach.  It is true, there have been some women that have died, particularly women in the Boston Marathon, from hyponatremia, their sodium gets too low, and that is why the Honolulu Marathon Clinic uses “power” pretzels, or has you drink salt.  You are allowed, as a runner, to have more salt than a sedentary person.  Dr. Scaff will cover that in another talk.

For more information on heat, heat stroke, and related topics, read Your First Marathon – The Last Word In Long Distance Running, by Jack H. Scaff Jr., M.D., F.A.C.S.M., available for purchase at the Honolulu Marathon Clinic on Sundays and online at: http://yourfirstmarathon.net/buy-online-today/

Next week:  Heat exchange.
 

Nutrition
For some good reading on nutrition, Dr. Scaff recommends everyone check out the daily postings on Dr. Alan Titchenal’s “Got Nutrients?” web site: http://gotnutrients.net/tips.cfm

Here is a recent posting from the “Got Nutrients?” web site:

April 4, 2013
A Japanese study of over 80,000 people that were studied over a period of 13 years found that both coffee and green tea consumption was associated with a reduced risk of cardiovascular disease and stroke.

Consumer Link
Coffee, Green Tea, May Help Lower Stroke Risk, Research Shows

Research Link
Stroke. 2013 Mar 14. [Epub ahead of print]