Determining Exercise Intensity

Sumo style kettle bell
This is actually pretty good form!
Frederick Winters during 1904 Summer Olympics
Old school is the new school with Kettle Bell training.

There are many ways to gauge exercise intensity. I’m going to discuss 3.

The most commonly employed method for the exerciser (even when they are unaware of doing it) is “perceived” exertion. That is, do you think you are working out hard. This method is used for both aerobic cardiovascular exercise and weight lifting exercise.

Since the vast majority of exercises have no idea what they are capable of, or even how to improve their capacity to train intensely, this method is often no better than a crude guess based on no facts.

For an experienced exerciser, this method can have varying degrees of validity; from somewhat valid to paramount validity, especially when partnered with the second method.

The 2nd method for determining intensity being used with increasing frequency is heart rate training using heart rate monitors (see my previous blog). These can be worn or built into machines like treadmills, stair climbers, ellipticals, etc. This technology’s aim is to take the guess-work out. A persons heart rate will always progressively increase in response to progressively increased activity. It’s the same science (to a lower level of intensity) that is used during a stress test. While commonly associated with cardiovascular and aerobic training, it can be used with weight lifting and other anaerobic activities, too.

The 3rd, and last method I’m going to describe is primarily used in conjunction with body building and other high intensity weight lifting exercises, but could also be adapted to other forms of anaerobic activity (sprints, plyometrics)as well.

Momentary muscular failure, known in weight lifting circles as the High Intensity Training Technique, describes the moment in an exercise set that you are literally unable to perform an additional rep. Very few people ever develop the conviction to achieve this result, and usually just stop when they hit a certain number of reps or decide that the set got hard enough.

For someone who has been working out consistently and hasn’t noticed much in the way of results in a while, this is the surest method to break thru a plateau. For someone trying to become as physically powerful, and/or develop the greatest amount of muscularity, as possible, they must eventually achieve this level of commitment. At this intensity, all other modes of determining intensity are of secondary importance or actually counterproductive. The only way to determine if you’re achieving this intensity level is to try another rep. If you succeed in completing it, you haven’t accomplished your goal, yet!  At this level, success is achieved at the moment you fail!

This method is best suited for the very experienced strength athlete in excellent overall health, as it puts tremendous stress on a persons musculoskeletal system and your cardiovascular system.

Fox and Haskell formula showing the split betw...
Image via Wikipedia


12 thoughts on “Determining Exercise Intensity

  1. I find that sometimes my perceived exhaustion is my mind faking my body out. I could probably do more but my mind says hey stop here. Since I’m sure if I was being chased by a rabid dog I would be able to keep running, so clearly I’m not exhausted but I guess I would also have the added bonus of extra adrenaline pumping through my body due to the fear factor. Should I really be wearing a heart rate monitor to get the full effect of a workout. I guess this would be where the personal trainers come in handy.

  2. An HRM (heart rate monitor) could easily remind you that what you’re experiencing in those situations is boredom with the activity, mental fatigue, and/or laziness. Sometimes you need to change the activity. Sometimes you need to switch workouts altogether; from cardio to weights or vice versa. Sometimes you need a day off. And sometimes you just need to suck it up. How committed are you to working out that day, and how committed are you to working out in general? Knowing you, the commitment isn’t the issue. if you’re having a bad running day, switch activity. Find the thing you can give your best effort and do that thing!

    1. Ha. How much are you willing to spend?

      Polar, Garmin, Suunto, even Timex, make excellent ones.

      They start at around $50, and go up to over $300. Do you want basic heart rate feedback? How about a cadence meter? GPS tracking for location/speed/mapping features? Elevation important? would you want to incorporate it into weight training? Triathlon training? There are so many possible feature choices, I really recommend you check out their websites. Or meet with me, we can discuss how you would want to use one, and then I’ll be happy to do the research for you.

  3. Effort is an issue I have trouble with as well. Your chart is interesting because how one determines “maximum” or “moderate” is difficult for me. I actually have an easier time with the measure of temporary muscle failure because it is a fairly simple yes/no decision point. One either can lift the weight something or one cannot. But “moderate” within an on-going activity, such as spin class, is both difficult for me to determine — and often is affected by how “up” I am that day — and it also needs to be in context. What is “moderate” for one minute of exercise is not what I would consider “moderate” for ten minutes of excise. The chart you show is clearly a point-in-time status and not an effort to be held over a period of time. I like the objectivity of that but that’s not how the brain works — at least not mine. If I know an exercise is for a long duration, my perception of “moderate” is affected.

    I like the idea of heart rate monitors because they don’t lie. But it can be difficult to translate beats per minute into exercises that are not purely aerobatic, such as Pilates or weight lifting. Perhaps you can cover the proper use of HRMs in future posts. I would like to know optimal heart rates or patterns of heart rates. I’m also interested in knowing the role of rest. When does recovery become laziness?

    Another form of perceived effort is pain. We live in a culture that says “no pain, no gain”. Whether discomfort is all that is required, I’m not entirely sure. New muscle seems to require the straining of current muscle to force adaptation. Perhaps you can explore good types of pain, when to seek it out and when not to.

    One of the basic problems behind effort charts and HRMs is that there is no good feedback mechanism that I’m aware of that identifies when a person is doing the right thing. If we went purely by how our body felt, we would probably never leave our massaging recliner chair. Physical appearance is a gauge often used, but that’s not even a reliable measure for physical stamina and strength. When it comes to measures of internal health and life expectancy, the picture is even murkier.

    In short: how do we know when we are doing the right thing?


    1. Well, HRM’s often have an alarm feature to let you know if you’ve gone below, or above, some predetermined intensity level. Even fairly inexpensive ones have an alarm to warn when you go below 60% THRZ (target heart rate zone). With weight lifting, if you’re trying to improve anaerobic recovery, my Polar FT-80 HRM will literally tell me when to pause an exercise, and when to resume it, based on my heart rate response, beeping at increasing volume levels until I comply. It also will predetermine up to 5 training intensity zones. Mine includes a recovery zone, moderate zone, high intensity zone, and extreme intensity zone. It also includes specific settings for weight lifting and aerobic training to further customize your workout. I choose the kind of workout. I choose which zone I want to train in. The FT-80 tells me when to start and stop my sets. The more I adapt to this training protocol, the longer I will be able to do each set before being told to to rest, and the shorter my rests will become. In the High intensity and extreme intensity zones, I will be pushing against my current lactic acid threshold with the purpose of elevating my future lactic acid threshold (SAID principle) so I can train longer when under extreme exercise stress. This could easily transfer over to other activities, eventually improving performance across a wide variety of physical activities.

      As for the pain issue. You know what the marines are told in boot camp? “Pain is weakness leaving the body”. Haha. We’re not going there though. Sharp shooting pain that occurs on repeated reps is always bad, wherever it is felt. Dull throbbing pain that gradually increases in intensity as continued reps are performed is always bad pain. Pain in bones and joints is always bad pain.

      On the other hand, momentary sharp pain that immediately dissipates leaving the affected area more comfortable is usually associated with scar tissue from past injuries breaking up, is good pain. Burning pain, gradually becoming worse, as a muscle continues through repetitions, is lactic acid. This is a necessary component of the anaerobic energy cycle and training as far through that as possible represents good pain. When the lactic acid levels reach a high enough level, your muscle’s ability to contract will temporarily shut down, forcing an end to the set. Typically, 60+ seconds after the set ends, the lactic acid will have been re-absorbed enough to allow the muscle contraction response to resume. The longer you wait, the less lactic acid will be floating around the muscle, which will allow you to perform more reps (or lift more weight) than you would have been able to accomplish with shorter rests.

      In anticipation of the next question; are short or long rests better; it depends completely on what your goal is. Stronger and/or bigger muscles are accomplished more efficiently with longer rests, so more lactic acid is recycled and the muscle can be pushed to lift heavier weights than otherwise possible. Muscular endurance with shorter rests, and athletic performance depends on the sport/activity, but usually includes components of both training styles in different degrees, at different times of the athletes training cycle.

  4. Your comment about scar tissue intrigues me. What do you mean by scar tissue? I assume it’s more than what results from an operation. How does one know they are dealing with scare tissue and not some other form of pain?

    1. Scar tissue results when any significant trauma or injury occurs to body tissue. It can accumulate from repeated injuries to the same area. It is tough, fibrous stuff that is intended to protect the area from similar injuries in the future. It could be considered an adaptive response. It can also accumulate slowly over time leaving the individual unaware that it’s happening until a significant amount builds up. It is stiff and can adhere to muscles, joints, and connective tissue interfering with normal movement, and cause pain at specific ranges of movement. Forcing the joint thru that adhesion can cause it to break away; think chipping off a lump of plaster from a wall. A typical example: I fractured my right elbow and wrist 13 years ago in a sport related situation. The cast was taken off after 10 days, and the doctor told me to start working out. He said it would hurt, but to go thru the fullest possible range of motion I could tolerate. First day back on the gym I started with dumbbell curls, and after a few modified reps I decided to go for it. 1/2 way up i felt an intense,sharp pain, that disappeared instantly, and my elbow felt significantly better. Subsequent exercises improved it more, and soon I was back to normal.

  5. I can see where the HRM can make sure one is staying in the correct exercise zone. I’ve also heard people talk about fat burning zone, aerobic and anaerobic zones. Which zones are useful for the average person to know and is there a guide to how to select which zones to use? For how long? In which order?

    And, how does interval training fit into zones? The reason I ask is because I can see someone doing intervals of fast sprints and slower movements without leaving a given zone.


  6. Zones are somewhat over rated. Fat burning zones have such low caloric/minute value that you would need to workout for 90 minutes continuously to get any significant benefit. 85% of burned calories will come from stored fat (after the 1st 12-15 minutes elapse). you might burn 200 calories in 60 minutes. 85% of 200 is 170 calories from stored fat (1 lb. of fat = 3500 cal). Moving up intensity into the cardio/aerobic zone and you’ll actually start to improve fitness, but because your body will be demanding energy more quickly it will have to rely on other sources besides fat; splitting fat burning and carbohydrate burning 50/50. So fat burning goes down, but in the same 60 minutes you could burn 500 calories. 50% of those calories are fat = 250 calories. More fat calories burned upfront than from working out in the “fat burning zone”. In addition, since you burned another 250 carb calories off, if they aren’t replaced by food you will create a significant calorie deficit and as you sleep your body will break additional fat down to replenish the carbs you burned earlier. In the long run, it doesn’t matter where the original calories come from, what matters is the deficit created. Higher intensities will burn greater calories/minute, but you will start tiring out sooner, and the initial calories will shift to ever greater percentages of carbs. But the end result still needs to be the calorie deficit if you’re trying to lose weight.

    Interval training is a method of manipulating high intensity training to prolong it, so ever greater amounts of calories can be burned. In addition, you’ll start developing specific adaptations to high intensity training which will allow you to train in the high intensity zone longer and shorten the lower intensity interval duration. It’s what happens to Army recruits in basic training. Marines on Paris Island take it further. Rangers and SEALs are for individuals who possess the ability to take it ever higher levels. So do most professional athletes.

  7. Keep in mind that you burn the highest percentage of calories from fat when you’re asleep. And no one suggests sleeping 15 hours a day is a good weight loss strategy (if only)!

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