Age-group triathletes and marathoners heart-rate monitor training

There is a lot to be gained when age-group triathletes and marathoners heart-rate monitor training is given serious consideration.

Even though heart-rate monitors are one of the best training tools on the market today when it comes to building endurance, conserving energy, and understanding pace, very few marathon runners or age-group Ironman triathletes take advantage of them.

The main reason may be that heart-rate monitors are not totally understood and often end up in the junk drawer in the kitchen after a few uses.

Here is a suggestion on how to use a heart-rate monitor to get the most out of it.
For example’s sake lets say you are training for a marathon and you want to record your best possible finish time and perhaps for the first time avoid the crash and burn death-march scenario.

Age-group triathletes and marathoners heart-rate monitor training

A heart-rate monitor used properly will not let you over-extend yourself.


This is the main thing and the most important lesson a heart-rate monitor will teach you. If you can learn to burn fat for fuel you will increase your endurance by leaps and bounds.

Learning to run in your aerobic zone as opposed to your anaerobic zone will teach your body to burn fat for fuel as opposed to glycogen.

The average marathoner has about enough glycogen stores to make it to around the 18 or 20 mile mark of a marathon if they run beyond their capabilities and it’s about at that point where they run head-first into the invisible “wall”.

It doesn’t matter if you eat 20 plates of pasta the week before an endurance event of any type, your body can only store a limited amount of glycogen. So in other words, more is not better if you are carbohydrate loading.

However, the average person who burns fat as their main source of fuel can run much, much further as stores of fat in the body are in greater supply than glycogen.

The moment you begin running above your own personal fat-burning heart-rate zone is the moment you begin using up your stores of glycogen.

For example: If a runner heads into a marathon hopeful of running a best ever time of 3:30 he will most likely fail if runs too fast at say a 3-hour marathon pace that is in his anaerobic zone and quickly burns through his available supply of glycogen.

If this happens he will lose energy, begin to run slower, then perhaps walk, and then simply struggle to the finish line in probably over four hours….far from challenging the personal best time that was the target going in.


Here is a simple method of finding your fat-burning heart-rate zone.

Subtract your age from 180.

-If you are 40 then you will come up with a figure of 140.
-If you you are in average shape or poor shape don’t change the figure.
-If you are in excellent shape and have trained extensively over the past year add five beats.
-If you are over 60 or a teen, add five beats.

Let’s assume you are using 140 beats per minute. Subtract 10 beats and that will give you 130 beats.

This is your aerobic fat-burning zone and where you will do the bulk of your training…….Between 130 and 140 beats.

Now you are set to go.


The very first thing to do is find yourself a quarter-mile outdoor track(400 meters)or indoor 200 meter track and run this test.

Using 140 beats(as an example only, as everyone’s will differ) as your personal magic figure go back five beats and over five beats from that figure and you will have a range of 135 to 145 beats per minute.

This is the zone where you will run your test only and your regular training will be between 130-140.

Warm up easily until your heart-rate is settled on your 140 aerobic target and begin your first 800 meter repeat with your heart-rate at 140.

The goal is to be right on 140 beats for each repeat or as close as possible. This means paying attention to your monitor watch. If you begin to edge up to 145 beats, then slow down to get it closer to 140. If you begin to slow down to 135 beast, then speed up a little to get it closer to 140.

This is a continuous test and is run non-stop,(walk, or speed-walk if necessary)until all five repeats are finished.

Be sure to start the test on a land-mark or line on the track you will remember. So if you are on a 400m track you do two laps and when you reach that start mark at the end of the second lap record your time and immediately begin recording the next lap start time. Follow these steps until all five repeats are completed.

There are many sports watches on the market that will have this function of recording repeats and storing them as you complete them and begin the next.

Age-group triathletes and marathoners heart-rate monitor training

There are many watches on the market that will record your interval times.

It is crucial that you stick to this format no matter how slow or fast you run otherwise it will not be accurate. Don’t worry about your speed. Just pay attention to what your heart-rate monitor says.

Normally, if this is done properly and as accurately as possible when you look at the results each repeat will most likely be slower than the one before with the final one being the slowest.

That’s normal.

After your test, record those five repeat times and put them away as you will need them to compare with when you re-do this test one month(and not before) down the road.


Lets say your big marathon is three or more months away. That’s a perfect time to take advantage of this training method.

After you have done your test begin to use your heart-rate monitor on every training run. Triathletes can also use a heart-rate monitor while bike training but for the purpose of this post on Ironstruck we are using the marathon as an example.

Whether you run three times or six times a week regardless of the distance follow these steps.

For the first five minutes of the run always run (or walk) if necessary to stay at 15-20 beats below your personal fat-burning heart-rate.

At the five minute mark ease into you fat-burning zone and hold it for the rest of the run session.

If you come to an uphill watch your heart-rate as it will begin to climb so you will have to slow down or perhaps even walk up steeper hills.

If you come to a steep downhill also watch your heart-rate because it will most likely go down and you may have to speed up.

At the end of the workout run or walk slowly for five minutes as you did in the beginning and let your heart-rate come down to well below your aerobic zone.

A 40-minute run session would look like this:

5 minutes at 15 or more beats below your aerobic zone(run slow or walk)
30 minutes in your fat-burning aerobic zone.
5 minutes at 15 or more beats below your aerobic zone(run slow or walk)

A 90-minute run session would look like this:

5 minutes at 15 or more beats below your aerobic zone(run slow or walk)
80 minutes in your fat-burning aerobic zone.
5 minutes at 15 or more beats below your aerobic zone(run slow or walk)

If you are seriously out of shape or with poor cardiovascular conditioning you may find that you have to run very slow or even power walk quite a lot. As difficult as this may seem, it’s very important to stick with it as over the weeks this will change and you will find yourself able to run faster at the same heart-rate.

If you are quite fit going in you may find that you are already running quite fast in your aerobic zone and if this is the case, make one or two of your runs recovery runs where you run 15 or more beats below your zone.

After using this method for two years I was running 6:30 miles in my aerobic fat-burning zone and it was too fast a pace for every single run workout.

At the end of one month repeat the same test you did at the beginning and follow the same instructions to the letter and again, record the times and put them beside the other five times from the first test and date them. Make sure that you use the same track as times on a 200-meter track will vary from a 400-meter track because of all the turns on a shorter track.

If you have let your heart-rate monitor be your guide in your previous four weeks of training you will see that your times have come down and you are running faster while remaining at the exact same heart-rate.

This means that without working your heart harder than you were the month before you are running faster…….and getting fitter……….and burning fat for fuel instead of glycogen.

These are all crucial elements for success in endurance events like the marathon or Ironman Triathlon.

Repeat this test every month and follow your progress. You will be amazed how your body will react.

When you get to within four or five weeks of your race (and not before)you could incorporate some anaerobic running into the mix for a bit of speed training or as some runners like to call it “tempo running.”

This was one of my favorite two-hour runs that I would do once a week for three weeks beginning with five weeks to go before the race. In other words, I always ramped training down in the final two weeks as I went into a taper.

5 minutes at 15 or more beats below my aerobic zone.
40 minutes at my aerobic fat-burning pace.
30 minutes at ten beats above my aerobic zone. So in this example using 140 as the high end of the aerobic zone, I would run at or close to a 150 heart-rate.
40 minutes at my aerobic fat-burning pace.
5 minutes at 15 or more beats below my aerobic zone.

So that’s a 120-minute run. I would run out for an hour and turn around and head back home.

Regardless of the distance you run-train with your heart-rate monitor you will often find yourself having a recovery run at the end of the session longer than five minutes as it’s quite normal for the return trip to take longer than the outward leg. There’s nothing wrong with that and it just means a few more minutes of easy running to cool your body down.

In the beginning it happened to me all the time, but as I got fitter it was amazing how I got closer and closer to the exact starting point of my out-and-back run as the months went by.

It was a sign that my endurance and fitness level were both improving.


Your success on race day will revolve on trusting your training and trusting your heart-rate monitor to guide you though the race.

It was pretty much the same scenario at the start line for all 35 or so of the marathons I took part in (or Ironman Triathlons for that matter).

Age-group triathletes and marathoners heart-rate monitor training

Run your own race.

Everyone there had trained for months or perhaps years for that moment in time and the adrenaline rush just before the gun was intense. Here you had all these athletes who were rested and ready and barely managing to control their anxiety.

This is where your marathon success begins and where you must take control of your own destiny and run your own race.

Watch your heart-rate monitor before the start. You want to stay relaxed as getting over-anxious will cause it to increase unnecessarily.

When the gun sounds there will be a stampede of runners taking off like there is no tomorrow. You don’t want any part of that, because most of those eager runners will be the same ones you will be passing in the late stages of the race as they run slowly or walk after their encounter with the wall.

***On race day you can up your heart-rate a little and still be aerobic because of your fitness level. Don’t go crazy but if your fat-burning zone as indicated in this example topped out at 140, on race day you can ease it up to 145-150 and still be in full control and be burning fat for fuel. In your first attempt at using a heart-rate monitor in a marathon after training with it, I would suggest for the most part staying around 5 beats above your training zone and see how you feel in the later stages of the race.***

As you begin to run, find a nice relaxed pace for yourself and ignore everything that is going on around you and stay in your own space. Ease your heart-rate up into your aerobic zone and keep it there.

It is critical that even if you feel like running faster that you hold yourself back and listen to your body.

It is sending vital heart-rate information to your monitor and you should take full advantage of it and let it be your guide.

As you approach an incline be prepared to slow down when you see your heart-rate begin to rise. Much like in training, the steeper the hill the greater the stress on your heart and it will rise.

Slow down as much as necessary in order to stay in your optimum fat-burning zone regardless of how many people pass you. Ignore them.

On the down-slope be prepared to take advantage of gravity. As is it easier on your body your heart-rate will drop. It’s free speed for you so pick up the pace until you are back in your fat-burning zone.

The further you go into the race the more people you will be passing like they are pylons on the road, yet you are maintaining the very same pace you started with.

….but they are not because it is most likely many of the same eager runners who took off like a shot at the start-line and are beginning to hit the wall.

They have depleted their glycogen stores with miles to go and you are still burning fat for fuel.

Now it will all start making sense to you and you will actually enjoy the closing stages of the marathon, especially if you have run them before and had the experience of hitting the wall and walking in the closing miles.

If you get to the point where there is four miles or so left in the race and you feel great it would most likely be safe to pick up the pace if you want to and are trying for a special time, like a personal best for instance.

You should have ample glycogen stores remaining to fuel a few miles at an increased heart-rate.

Age-group triathletes and marathoners heart-rate monitor training-heart-rate monitor

Have you best marathon finish ever.

Within the last mile or two there is no reason to hold back if you feel great and at this point you can even ignore your heart-rate monitor and just for it.

The fact that you will be passing struggling runners by the dozens will give you a huge lift.

Best off all, after you cross the finish line with a great marathon result in the bank you will most likely have an excellent and speedy recovery from the race because you did not over-tax yourself.

This is also an excellent strategy for cyclists to use in the Ironman Triathlon and it will greatly help in conserving energy for the marathon.

The biggest difference triathletes will notice between run training and bike training with a heart-rate monitor is that they will actually have to work harder to reach their aerobic fat-burning zone on the bike.

This is because you are on a machine and it is doing much of the work and it’s quite normal to experience this. Just go with the flow and bike until you get into your aerobic zone and keep it there for your bike session.

Be sure to use the same warm-up and cool-down format as you would in run training.


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About Ray

Ray hasn’t stopped since his first Ironman in Kona, 1984. He has since run 14 more Ironman races, authored 5 Triathlon books, and is now bringing together a passionate community of triathletes. Contact Ray at

4 thoughts on “Age-group triathletes and marathoners heart-rate monitor training

  1. Great blog! Do you have any suggestions for aspiring
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  2. Dear Ray, does this also aply for 10K and 21K? Because Ive been working how you detailed it and my times are now doble of the originals.
    Im 57 and my area would be 123 to 133. Kind regards

    • Thank you for your post..

      It is a system geared toward longer distances like the marathon or Ironman, but should also have benefits in a half marathon. This is not a quick result. It takes months to build up your fat-burning ability and it’s important to stick with the program.

      At first you will feel like you are running very slow on your training runs.

      But as you get more fit you will find yourself running faster while still staying in your fat-burning zone.

      At you age when you race you can use a heart rate zone about ten beats above the zone you calculated.

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