Doc’s Talk 03-31-2013

Because everybody wonders about sprinting, Dr. Scaff talked about how to judge if you are running at the right pace without going through the expense and time of calculating maximum pulse rates, percentage, etc., i.e. the Talk Test.

If you read books on running you will see a lot of complicated formulas to determine your optimal heart rate when you are running, known as “when you are in the zone.”

Basically, heart rate is related to age.  As you get older your heart gets slower and then one day it stops.  When you are training at 75% of your maximum heart rate, you are going from the aerobic, oxygen burning threshold, to anaerobic or the sprint.  Nobody can sprint a marathon, so you have all these pulse rate monitors, etc. to determine your optimal heart rate.   

Ways To Calculate Your Maximum Pulse Rate
One way to calculate your maximum pulse rate is 200 minus half your age,…
Or 220 minus your age.

In the example of a 40 year old:
Half of 40 is 20, 20 subtracted from 200 is 180,…
Or, 220 minus 40 is 180.

Then you calculate 75% of that (180 x 0.75) which comes out to about 130 to 140 beats per minute.

The Talk Test
When you start sprinting you are relying more on carbohydrates and start to become breathless. If you have a person increase their running pace until they stop talking and you take their heart rate, they are at their threshold heart rate.  The beauty of this is it works at altitude.  If you are at altitude you get out of breath faster, that tells you when to slow down.  We call this the talk test and it has been validated in the literature.

So you can do other things to calculate heart rate, but remember, that heart rate is linear to age, but there is some biologic variation, for example, a man or a woman might have a maximum heart rate of 180 but in that same age group some will be 175, some will be 185, so the talk test is actually better than trying to get into these different kinds of zones.

So, to determine your optimal heart rate using the Talk Test:  You never run so fast you cannot talk, and you never run so slow that you can sing.  It works perfectly and that is all you need to know about calculating your heart rate.

Running Fuel:  Carbohydrates & Fat
Last week Dr. Scaff talked about quick twitch, slow twitch fibers, and that quick twitch burn carbohydrate, the slow twitch burn fat, and we switch into fat metabolism after 40 minutes of running, but, we’re burning 80% fat; …however, fat is like bunker fuel, it is very inefficient.  Fat will let you run forever at a slow pace, but you have to top it off with the high-octane fuel, which is carbohydrate.  When you’re running and you are in fat metabolism you are burning your own fat, so that is good, so don’t worry; …but when you are running for competition or anything else you want about 10% carbohydrate to burn, which is why they have carbohydrates in the form of drinks of some kind at the various aid stations, and also why the Honolulu Marathon Clinic serves “power” pretzels (i.e. the standard pretzels you buy at the grocery store), which are a very good source of carbohydrate and salt.  When Dr. Scaff talks about salt later this season, you will find out you need more rather than less salt no matter what your doctor tells you.

The Best Time of Day to Lose Weight from Running
Running in the morning probably will help you lose weight faster than in the afternoon because you are not eating at that point in time.  If you get up and run before breakfast, you switch into fat metabolism more quickly, and you burn your fat until you eat.

We’ve been told all our lives that if you don’t start out with a good breakfast you are ruining your health, and that you’ve got to have 3 meals per day.  Dr. Scaff recently found another good study showing 2 meals per day or 1 meal per day is ok if you like that.  So if you don’t want to want to eat breakfast, you don’t have to, and while everybody will scold you, you’ll be just as healthy as if you had eaten breakfast, except you’ll be losing weight a little bit faster.  Of course you stay in fat metabolism burning your own fat, until you break the cycle, which is when you start to eat.  Most people have lunch before they run, they run in the afternoon, whereas in the morning you have been asleep for several hours and you are basically in a fasting position, which is why we call it breakfast; we are breaking the fast.

For more information on these and other running-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:

Next week:  Heat, what’s good about it, and what’s bad about it, because it is a byproduct of exercise.
For some good reading on nutrition, Dr. Scaff recommends everyone check out the daily postings on Dr. Alan Titchenal’s “Got Nutrients?” web site:

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

March 31, 2013
The micro-ecology of the bacterial population in the human colon is proving to play a substantial role in overall health. The types and amounts of various bacteria may be influenced by both the foods we eat and the bacteria present in or on those foods. New research found that the types and relative amounts of bacteria present on surface of fruits and vegetables commonly eaten raw can vary due to many variables, including farming practices.

Consumer Link
Diverse Bacteria On Fresh Fruits, Vegetables Vary With Produce Type, Farming Practices

Research Link
PLoS ONE 8(3): e59310. doi:10.1371/journal.pone.0059310