2 Slow 4 Boston: Lactate Threshold

Before Coach Wadsworth could make me a suitable training schedule, we had to figure out what kind of shape I was in. By shape, I mean what my lactate threshold is, and I'm not referring to when my mammary glands start milking. For those that have no idea what I'm talking about:

Lactate Threshold is the exercise intensity at which lactate starts to accumulate in the blood stream. That may insinuate that lactate is bad, but really it is just a byproduct of lactic acid along with hydrogen ions which are the real problem. Hydrogen ions cause an acidic environment in the muscle, a process referred to as acidosis. Acidosis interferes with muscle contractions, causing fatigue.

So a lactate test is just another way to measure the amount of hydrogen ions that lead to acidosis, and therefore is an indirect marker for fatigue. I spent about an hour studying that and trying to put it in layman's terms. Is it still clear as mud?

So that's all well and good, but how does knowing all that help my training? The answer is, by knowing what my threshold is I can train at the highest intensity possible for the longest time while improving my ability to conserve energy and fight fatigue. Obviously, we can't train like that all the time or we would become "overtrained" or injured. The general guidelines state that this intensity of workouts should only makeup about 10 to 20 percent of total mileage for the week.

On April 24th, I met up with coach at his training center. To conduct the test, he had me put on a heart rate monitor, and warm up on a treadmill for about 10 minutes. After that he started to increase the incline and the speed every couple minutes. After each increase he would have me rate my perceived level of exertion on a scale of 1 to 10. Then he would have me place my hand (while I was running) on the frame of the treadmill while he pricked it to get a blood sample. He measured the sample with a digital machine and marked down my lactate level along with my heart rate. To finish the test he turned into a sadist and upped the incline to 8% and the pace to 8 mph until I cried ~~uncle~~. He said he did that to find my max heart rate, but he was smiling a lot when he said it, so I think he was just wanting to see me suffer.

This is the lactate test kit that was used on me. The white and blue tool at the bottom is used to prick fingers.
The black canister holds little litmus type strips of paper used to collect the drops of blood,
and the yellow device is a digital meter used to measure the amount of lactate in your blood.

This is simply a chart to record all the heart rate and
lactate levels as the test progresses.

Now for the moment we've all been waiting for: Nathan emailed me a letter containing my results along with an explanation of the test. I've posted the letter below in its entirety.

A treadmill graded exercise stress test was performed 4/24/12. A 12.5-minute warm-up at 3.5-5 mph was carried out prior to the test. During the first stage of the test, you maintained a running speed of 6 mph with a 0 degree incline. The incline increased to 8%, while the speed increased to 8 mph by 16:30 minutes. During the test, you reached a maximum heart rate of 197 bpm. The “will to stop outweighed the will to keep going” and “no finish line” were the reasons for ending the test, although a Rate of Perceived Exertion (RPE) of 9 out of 10 was achieved indicating a near-maximal effort. Blood Lactate levels of 4.0+ mmol/L were achieved at 16:00, which means that your body has gone over the lactate threshold value. This indicates a switch from having a surplus of oxygen to going into oxygen debt (or the amount of carbon dioxide that your body is removing by ventilation is greater than the amount of oxygen you are able to breathe in). Namely, you have gone over your lactate threshold.

Improving lactate threshold and mechanical efficiency can be accomplished by performing interval workouts above your lactate threshold heart rate of 183 bpm. Quality aerobic training needs to be carried out in the heart rate range of 130-180 bpm, which is below your lactate threshold. Tempo runs at or just above or below your lactate threshold heart rate of 183 bpm will increase your lactate threshold and allow you to improve your aerobic fitness level.

Strides and tempo runs will help you to run faster and more efficient. Be sure to perform your recovery runs at a HR of 130-150 bpm. This level will ensure that you are recovering adequately. With the implementation of these suggestions you will be able to improve your running times.

Heart Rate Training Zones:

Easy/Recovery Zone: 130-150 bpm

Aerobic Maintenance Zone: 151-180 bpm

Threshold/Steady Zone: 181-186 bpm

Interval Zone: 186+ bpm

A re-test in six weeks would be beneficial and should show improvement.

Now with a lactate threshold in hand, a customized training schedule can be developed where some of my workouts will be ran at that threshold. If you'll notice, Nathan also gave me zones for Recovery, Aerobic, and Interval. This should help me to know how fast to run based on the day's objective.