Training For Endurance

As my races have progressed from Sprint Triathlons to now full Ironman distance, I’ve focused on training smarter. I knew that I didn’t have the time to put in 15-20 hours a week of training like most people gearing up for an Ironman do, so I had to figure out the smartest way to train…making the most of every training session.

One of the key components to training for a long distance race, such as Ironman, or even a marathon is to build endurance – making your body an aerobic machine! Last season I based my training plan on a book by Joe Friel. This season, I’m training under the guide offered by Ben Greenfield. Both of these triathlon coaches focus on using your heart rate as a tool to train smart. With the exception of swimming, I have my heart rate monitor on during every training session. Monitoring my heart rate is critical during some workouts, and not important during others.

About once every six weeks, I do a test to determine my heart rate zones. The tests consists of finding my Lactate Threshold heart rate while running and biking. This test is not fun! It’s basically going all-out for 30-40 minutes…which seems like an eternity when your lungs and legs are burning! Based on what my LT heart rate is during this test, I find all of my heart rate training zones. During my last running test, my Lactate Threshold HR was 167 bpm. Based on Ben Greenfield’s method, to find my aerobic (endurance) training heart rate, I subtract 20 bpm from this number. So my endurance training should take place at 147 bpm (+/- 5 bpm).

Once every week or so, I do a long run (or ride) in my endurance heart rate zone. For instance, this past weekend, I did a 14 mile run with an average heart rate of 151 bpm. This translated to a pace of 8:09 min/mile. The pace wasn’t my concern – the heart rate was. I kept a constant eye on it. If it jumped above 152, I would slow down. If it dropped below 142, I’d speed up. This isn’t easy to do on hills, but I try. Here’s my heart rate data from that run:

So why train this way? To condition your body to use fat as fuel. At higher heart rates, your body uses glycogen (carbohydrates) as fuel. The problem with this is that your body can only store small amounts of glycogen that is available for burning as fuel. Once you’ve used this up…you “hit the wall”. The good news is that we can store lots of fat for fuel. This burning of fat storage is what gives us the energy to make it through endurance events.

So based on this knowledge, I’m always trying to make sure that I’m training in my aerobic zone so that my body becomes efficient at burning fat instead of glycogen. While the method of testing and finding my aerobic heart rate based on my LT heart rate is pretty accurate, I always like to double-check this number. I recently came across an author that wrote the book called “The Big Book of Endurance Training and Racing”. His name is Dr. Phil Maffetone and he has developed an alternative method to finding your aerobic heart rate.

The “220 minus your age and use 70%-80% of this number” formula has been used for years, but I can tell you that it’s not accurate. For me, this would put my aerobic zone between 130 and 149 bpm. While that get’s me close on the high side, running at 130 bpm would be too low and would offer me very little benefit.

Dr. Maffetone’s formula involves taking 180 and subtracting your age. This number by itself is not useful. You must then make adjustments based on your current state of fitness and health.
A) If you have or are recovering from a major illness (heart disease, any operation or medical condition), subtract an additional 10 bpm from your number.
B) If you are currently injured or have taken time off from training, have a cold or the flu, or train inconsistantly, subtract another 5 bpm.
C) If your have been training consistantly (4 times a week) for up to two years without any of the above mentioned problems, keep the number (180 minus age) the same.
D) If you have been training for more than two years without an of the problems listed above, and have made progress in competition without injury, add 5 bpm.

So for myself, I took my age (soon to be 33) from 180. This gave me 147.
Looking at the categories listed, I think that “C” is the most accurate for my current fitness and health. So, I left my number at 147 bpm.

This is very encouraging since it’s the EXACT same number that I came up with after subtracting 20 bpm from my most recent LT heart rate test. It’s always a good feeling when you confirm that you are doing the right thing!

3/19/11: Run – Long Aerobic Run (14.00 miles in 1:54:08 – Avg HR = 151)
3/20/11: Bike– Long Aerobic Ride (40.13 miles in 2:00:51 – Avg HR = 132)
3/21/11: Run – Cadence counting intervals (5.09 miles in 40:28)
3/21/11: Weights – Dry Land Superset for swim strength x 4

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