Although “lactate threshold” is one of the most common buzzwords surrounding training for triathlon, many athletes don’t realize its importance in improving performance. Understanding and knowing your lactate threshold can help you get the most bang for your training buck.

THE BASICS

The What
Lactate: A chemical compound produced during processes of energy metabolism.

Lactate threshold: The point during exercise at which the rate of lactate production exceeds the rate of lactate removal. The mechanism of removal in our bodies is our “buffering system.”

The Why
At rest or during aerobic exercise, our body shunts the precursors of lactate back into the energy cycle, using them for more energy. As we reach anaerobic exercise, our system’s capacity to do so is overcome, and those precursors start turning into lactate.

Knowing that threshold at which your individual buffering system is overcome can help you to train at that threshold and become more efficient at turning lactate back into energy. This translates to higher quality training of your aerobic and anaerobic energy systems when you know concrete numbers for the boundaries of those systems.

FINDING YOUR LACTATE THRESHOLD

The How
The gold standard for testing uses finger pricks measuring blood lactate during exercise—not too practical. It obviously hurts your fingertips, and last time I did it I got blood on my argyle compression socks. Boo hoo.

Field Testing
There are several out there that use heart rate to estimate lactate threshold. You want to go into these tests rested, hydrated and having eaten a normal carbohydrate meal a few hours prior. You also want to perform them under as standardized conditions as you can find, such as on a track or bike trainer.

You can test lactate threshold heart rate when both cycling and running to get your individualized lactate threshold estimate for each sport. Start with a 10- to 15-minute warm-up, then do 30 minutes of all-out effort at a pace you can sustain for the entire period. Record your average heart rate for the last 20 minutes of that 30-minute workout session, and you have your estimate of your lactate threshold heart rate.

The key to this test is to know how fast to start out. It’s imperative to maintain a sustainable, constant pace the entire 30 minutes.

Sophisticated?
Do you have resources available that fall somewhere in between a heart rate monitor and a blood lactate analyzer? Are you good at listening to your body? If so, Ben Greenfield at Pacific Elite Fitness formulated a more sophisticated test for cycling utilizing power measurements, cadence and heart rate, all of which are graded by biofeedback. His test gives you lactate threshold wattage in addition to heart rate.

To do Greenfield’s test, replace the Xes below with your usual power measurements. Start with an easy wattage and add watts in increments that put you near your max after six increases or 30 minutes.

Warm up and start at X watts and spin for 10 minutes at 90 rpm. At this point, increase in X-watt increments every five minutes. Record the wattage and heart rate at which deep breathing is required and legs begin to burn. This should feel like a seven or eight on a 10-point scale or a 40km time-trial intensity. You must be able to maintain 85 to 90 rpm to keep the test valid. Voila, your threshold heart rate and power are in front of you when those signs become apparent.

USING YOUR LACTATE THRESHOLD

Here is the big secret and the reason that lactate threshold may be your best overall predictor of fitness: As you become more fit, your lactate threshold heart rate starts to approach your V02 max heart rate. V02 max is your potential, while lactate threshold is how much of that potential you are reaching. Nobody ever really reaches that full potential; even elite athletes can have lactate threshold heart rates that are only 80 percent their VO2 max heart rates. This may be closer to 50 percent in untrained athletes.

With training, you can better approach your potential for lactate clearance. When you have extrapolated your heart rate or power levels at threshold, you can train around those values and make yourself more efficient at clearing lactate.

Workouts
This is where you get to be creative. Spending some time near, right at or over your lactate threshold heart rates will allow you to get better at clearing it as you make it.

Example 1: Work at 5 percent below your lactate threshold, increasing the amount of time you spend there each week.
Example 2: Spend as much time as you can right at your threshold heart rate and watch that amount of time improve each week.
Example 3: Alternate from heart rates right below to right above your threshold, learning to clear lactate on the fly as you would when racing.

Don’t forget to periodically retest yourself. You will get to watch yourself improve, and you will ensure that you are still maximizing your time.

Works Cited:
Greenfield, B. www.pacificfit.net

Boulay MR, Simoneau JA, Lortie G, Bouchard C. Monitoring high-intensity endurance exercise with heart rate and thresholds. Med Sci Sports Exerc. 1997 Jan;29(1):125-32.

Plato PA, McNulty M, Crunk SM, Tug Ergun A. Predicting Lactate Threshold Using Ventilatory Threshold. Int J Sports Med. 2008 Jan 23

Roseguini BT, Narro F, Oliveira AR, Ribeiro JP. Estimation of the lactate threshold from heart rate response to submaximal exercise: the pulse deficit.
Int J Sports Med. 2007 Jun;28(6):463-9. Epub 2006 Nov 16.

Van Schuylenbergh R, Vanden Eynde B, Hespel P. Correlations between lactate and ventilatory thresholds and the maximal lactate steady state in elite cyclists.
Int J Sports Med. 2004 Aug;25(6):403-8.

Cameron Chesnut is attending medical school at the University of Washington. He has a background in sports nutrition and physiology, and he uses this knowledge to piece together the everyday medical mysteries of sport. Cameron is also an avid triathlete, having trained at the Victorian Institute of Sport in Melbourne, Australia, and is currently preparing for Ironman Coeur d’Alene.

Cameron races to promote health care education and access; he is supported by Garage Town USA and Under Armour Performance Apparel.