Triathlon for Weightloss? Part 2: Interval Training and Target Heart-Rate Zones

author : acbadger
comments : 1

Here is where we are going to get a little technical on you…but, trust me, it’s “easy” technical stuff.   (See part one of this series: Triathlon for Weightloss? )

First and foremost I am a HUGE advocate of interval training. Interval training is an exercise training strategy that involves alternating short, intense bouts of exercise with short recovery periods of exercise, therefore increasing and decreasing your heart rate in intervals. Interval training burns more calories in one session than its consistent heart rate workout counterpart (i.e. Fartleks vs. a long steady paced run). Interval workouts have also been noted to improve one’s resting metabolic rate (RMR) as well as one’s VO2 Max (the maximum amount of oxygen that can be used by an individual, in milliliters, in one minute per kilogram of body weight).

These interval workouts can be done in 15 to 20 minutes and have huge caloric expenditures for those who are crunched for time and want to get the most out of their workouts.


*NOTE, please allow for a proper warmup and cooldown for intervals.  Intervals are not recommended for those new to exercise but for those that have been in a routine and can already do the total time of the workout without a problem and have been doing those times consistently.

Another way to monitor fat loss is to find your heart rate zones. There are three essential zones that we’ll talk about today.

  • Resting Heart Rate (RHR): The rate at which your heart beats while you are at rest. Best taken when you get up first thing in the morning.

  • Recovery Zone: 55% to 65% of your Maximum Heart Rate (MHR)

  • Aerobic Zone: 65% to 80% of your MHR

  • Anaerobic Zone: 80% to 90% of your MHR

It is most beneficial for one to remain in the 65% to 80% Aerobic Heart Rate Zone. I say this because this is the level at which you will work, and feel as though you are working, but still remain fairly comfortable. You should be able to perform the “talk test,” in which is the ability to hold a conversation while exercising. If you are working so hard you can hardly get in a single breath, it’s time to ease up a bit.

Now, that being said, if you opt to try the interval training program, you will have shorts bouts of time where speaking will be difficult…but that, again, is why you are performing SHORT bouts of exercise at that level.

There is a VERY simple equation to find your personal heart rate zones if you are brand-new to exercise.  The formula is the '220-Age' formula.  220 minus your age is calculated to be your maximum heart-rate. For example, if you are a 35 year old male trying to figure out your Aerobic Zone:

  • Take the number 220-35 (your age)= 185 x .65 = 120.

  • Then take 220-35 (your age) = 185 x .80= 148.

  • So, your Aerobic Heart Rate Zone is between 120 and 148 beats per minute (bpm).

If you are a female age 39 trying to find your Aerobic Heart Rate Zone,

  • You will take the number 222 (as a woman’s heart tends to beat at a faster rate than a mans) – 39 = 183 x .65= 119

  • Then 222-39=183 x .80= 146.

  • So a 39 year-old female's Aerobic Heart Rate Zone at 39 years of age is between 119 and 146.

*NOTE, this is not the only way to find your heart-rate zones.  There are others (Lactate Threshold, LT) that, as you gain fitness and build up a base, can be more accurate.  But they require fast time-trials and are more rigorous on the body.  If you are new to exercise or just getting your feet wet, the 220-Age formula gives you a decent starting point until yo ubuild up your fitness to do the more accurate, LT test.

Another way to ensure weight loss is to weight train. A body with more muscle mass will burn more calories at rest than a body that has more fat mass. For example, if I am a 130 pound woman with a body fat percentage of 24% and have a friend who weights 130 pounds but has a body fat percentage of 30%, even if we do the exact same job during the day and do the very same workout at night, I will burn more calories at rest than my 30% body fat counterpart.

Women are often under the impression that if they lift weights they will bulk up. This is genetically impossible. Women have too much estrogen and are not able to bulk up like men (who have more testosterone) can. So, put that weight lifting urban legend aside and pump some iron…your body and scale will be glad you did!

Check in with me next month when we discuss food, caloric deficit and hydration for weight loss.



Q - So I have my 3 zones per the 220-age formula, what part of zones is considered 'the interval' - is it the anaerobic? or the top end of the aerobic zone?

A - The aerobic (with Oxygen) zone is 65% to 80%. You should be able to do the ‘talk test’ and be able to hold a conversation while exercising in this zone.

The anaerobic zone is higher/closer to your max heart rate which is 75% to 85% of your maximum heart rate. If you are having difficulty breathing (VERY winded) or cannot talk during your workout, you are working in your anaerobic zone.

Interval workouts are when you go from your aerobic to anaerobic zone in intervals (5 minutes in your aerobic zone and 1 minute at your anaerobic zone).


Q - How 'short' of session should the 'intervals' be? At what %MHR? How long should my recovery be in-between intervals? The target %MHR for recovery before the next interval?

A- Intervals do not have any exact time frame. They are individual and depend on the person. You can jog easy for 5 minutes, sprint hard for 2 and then take up to 8 minutes at an easy jog to recover until your ready to sprint again. The key is to let your heart rate drop back down to about 65% to 70% before starting another hard (anaerobic) interval. Owning a Heart Rate Monitor is very beneficial when you are working with Heart Rates and interval workouts.

Your Max Heart Rate should be no higher than what you have figured for your highest zone (typically 82% to 84% of your max heart rate).

For the next in the series, I will detail a workout in the next series. I will add it to the nutritional aspect of weight loss for a ‘meal plan’ and exercise informational component.

Until then, be well and stay fit!


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date: March 21, 2007



Four Sprint Triathlons and 2 Olympic Distance Triathlons. Several marathons and Boston qualified. Because of my new found love of these sports, I got my Personal Training Certification and USAT Level I Coaching Certification so I could help others attain their goals!



Four Sprint Triathlons and 2 Olympic Distance Triathlons. Several marathons and Boston qualified. Because of my new found love of these sports, I got my Personal Training Certification and USAT Level I Coaching Certification so I could help others attain their goals!

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