Strength Training Just Doesn't Burn that Many Calories

Azdak

At least not directly. It's still essential for weight loss, especially long-term, and for overall fitness and health. But when it comes to including resistance exercise in your overall calorie plan, I would exercise caution, especially when it comes to "eating back" the exercise calories.

Oh, and, as I have said before, you CANNOT use a heart rate monitor to estimate strength training calories.

You might well ask: Yo, Azdak, why are you writing this as a separate topic? You say this all the time anyhow.

I have had a couple of slow days at work going into the holidays. A lot of people are cancelling appointments, going on vacation, etc. I sometimes use the time to wander around the ol' PubMed database, looking at topics of interest and catching up on journals that I'm too cheap to pay for.

While there is now a great PubMed app for both iPhone and Android, you only get abstracts. I work for a hospital-based fitness center so we have access to the library network for our large corporate healthcare system. And that includes full access to many articles.

It is often important to read an entire research article to glean the real details. Often an abstract will say things like "followed a traditional weight lifting protocol" without describing the routine; or they will report a "significant increase in post-exercise calorie expenditure" without listing the raw numbers.

I have been looking at two things: energy expenditure during resistance exercise and EPOC (elevated post-exercise oxygen consumption) following resistance training. It was not an exhaustive search by any means, but here are a couple of trends:

First of all, direct oxygen uptake/calories burned during traditional strength training is modest at best. I reviewed at least a dozen studies and all said basically the same thing: For medium to high intensity weight lifting, average intensity is about 2-4 METS. One study looked at a comparison between supersets (one set agonist muscle immediately followed by one set antagonist muscle, then recovery) and traditional sets (one set, recovery, next set, recovery, etc). They did 24 total sets of 10RM intensity, lasting 35 -40 plus minutes. Total calorie burn: about 260. And these were college-age males. Other studies reported similar number, even with intensities of 4-6RM.

As I have stated before, elevated heart rates during strength training are misleading. That's because, unlike during aerobic exercise, an elevated heart rate during strength training is NOT accompanied by an increase in oxygen consumption. It is the increase in oxygen consumption that drives increased caloric expenditure, NOT increased heart rate per se. So if you are lifting weights, and your heart rate skyrockets--which it can, esp if you are relatively untrained--that big number on your HRM is misleading. The HRM doesn't know the difference between an elevated HR due to aerobic exercise, or one elevated due to strength training, stress, temperature, illness, etc., so it just spits out the same number. You are not burning that many calories directly during the workout.

And you probably aren't burning all that much after the workout, either. In the study referred to earlier, EPOC was negligible. Although, the study authors claimed statistical significance for the fact that "Superset exercise had a 30% higher EPOC measured for 60 min following exercise", the total amounts were like 19 calories to 14 calories. That's not per minute or per Kilo -- that's total.

That's on the low side--other studies have reported higher numbers, but nothing more than 100-150 total calories. In fact a review of a number of studies looking at EPOC concluded:

"the earlier research optimism regarding an important role for the EPOC in weight loss is generally unfounded. This is further reinforced by acknowledging that the exercise stimuli require to promote a prolonged EPOC are unlikely to be tolerate by non-athletic individuals. The role of exercise in the maintenance of body mass is therefore predominantly mediated via the cumulative effect of the energy expenditure during the actual exercise. "

As I began, this doesn't mean that strength training is unimportant. We know that it is. We know that strength training has benefits that cannot be explained by the direct caloric expenditure or the EPOC alone. So, just be conservative with your calories and enjoy the benefits.

bbygrl5

I always love reading what you post. Based on all of this, I know it's impossible to answer this, but in your best guess from doing 1/2 an hour of moderately hefty lifting (about 60 lbs on most arm and leg machines), is it reasonable to estimate I burned at least 90 calories? I know it would be just a guess, but if I can eat 90 extra calories, I'm gonna do it! lol

fromaquasar

Thanks for this! Another interesting and informative post, I have been doing nearly pure cardio the last few weeks but have just got myself a strength programme as I would like to build some tone and strength too

pinkarrow

I love reading your posts, they're packed FULL of information and it really helps me out when it comes to my tracking calories! Please keep doing what you're doing and keep us well informed!

IsMollyReallyHungry

Thanks for research Azdak! And I got it before and I get it now. Thanks for reminder. When I am done with my cardio I will stop my calorie count.

Ge0rgiana

Last night I resumed my little bit of strength training that I was doing before. I had quit because, even though it was only a little training, it was hard and very painful. Now that I've been on an increased dose of dessicated thyroid for a couple of months, the pain has really dissipated. It still doesn't feel great, but I'm feeling way better, and I think I'm more than ready to give this another go.

Thank you for reminding me why I needed to start doing this again and how important it is. You really are extremely insightful, and your posts are always a good read. :flowerforyou:

tiffanygil

very interesting! Thank you. Did this study include non traditional strength training? Such as circuit training where you don't rest?

Azdak

I always love reading what you post. Based on all of this, I know it's impossible to answer this, but in your best guess from doing 1/2 an hour of moderately hefty lifting (about 60 lbs on most arm and leg machines), is it reasonable to estimate I burned at least 90 calories? I know it would be just a guess, but if I can eat 90 extra calories, I'm gonna do it! lol

Yes, I think 90 is ok.....oh, what the heck, be brave, be bold......GO FOR 100!!

bbygrl5

I always love reading what you post. Based on all of this, I know it's impossible to answer this, but in your best guess from doing 1/2 an hour of moderately hefty lifting (about 60 lbs on most arm and leg machines), is it reasonable to estimate I burned at least 90 calories? I know it would be just a guess, but if I can eat 90 extra calories, I'm gonna do it! lol

Yes, I think 90 is ok.....oh, what the heck, be brave, be bold......GO FOR 100!!

lol, okay.. since you said it was okay! lol j/k, j/k.

Azdak

very interesting! Thank you. Did this study include non traditional strength training? Such as circuit training where you don't rest?

It depends on the nature of the circuit. Just moving from strength machine to strength machine, lifting say 8-12 RM weights, is not that much different than what I described. Again, just because heart rate is elevated, that doesn't mean you are burning more calories--that's what I described earlier.

As a general rule, there is an inverse relationship between resistance and oxygen uptake/cardio effect (that's gross oversimplification, but it will have to do for how. In other words the higher the resistance, the greater strength gains and the less cardio response/direct calories burned. At the other end, when doing high-level cardio work, direct caloric burn is much greater, but strength gains can be modest/minimal.

As you move along the continuum, the ratios change. If you get to what is commonly referred to as a "metabolic circuit", you will get a higher aerobic component/calorie burn, but less in the way of direct strength gains. In other words, if you go from doing 4-6 sets of bench press, lifting 2-5 RM weight and switch to something like cross fit, or even P90x (as I understand it), your max bench press weight will decrease. You may not care, because you like the other benefits of that type of exercise, but that's a different discussion.

Once you get into these types of "hybrid" workouts, the effects begin to change. There seems to be more of an "aftereffect", if it is truly a high-intensity workout. There is not a clear understanding of why HIIT type workouts can result in greater fat loss, at least in the short term, but we know it happens. It just doesn't seem to be as a result of either increased direct calories burned or increased EPOC.

HRMs can be a little more reliable during circuit or metabolic type workouts, but they will still likely overestimate calories. That is because upper body work, especially overhead, results in an exaggerated HR response--so again, the HRM thinks you are burning more calories than you are, sometimes by 25%-35%.

My main goal is writing these articles is NOT to discourage strength training workouts, metabolic circuits, HIT or anything similar. If you can tolerate the effort, they can be VERY beneficial. Mostly, I am trying to warn people against eating back large numbers of strength training calories based on inflated HRM numbers. If you do a good lifting workout, take your 200-300 calories and refuel afterwards.

In my case, my HR doesn't go up that high with strength training, so it's not an issue. By coincidence, my HRM numbers are probably fairly "accurate" (although I never look at them).

TaraMaria

You sir are amazing. When you replied to my lung question the other day, I actually called a friend of mine and read your reply. I'm going to have to share this info too. Its hard for me to buckle down and strength train. I love seeing the high number of calories burned when I do cardio. However now, I've been sitting at my goal weight for three months I know that its important to build strength. Its just a change in thinking. Thanks so much!!

HealthyChanges2010

bump

Azdak

You sir are amazing. When you replied to my lung question the other day, I actually called a friend of mine and read your reply. I'm going to have to share this info too. Its hard for me to buckle down and strength train. I love seeing the high number of calories burned when I do cardio. However now, I've been sitting at my goal weight for three months I know that its important to build strength. Its just a change in thinking. Thanks so much!!

The closer you get to your "goal", the trickier the process becomes. It becomes harder to sustain a calorie deficit because of the imprecision of all of our measuring methods--HRM or otherwise. That 15%-20% error factor doesn't mean as much when you are 50-60-70, etc pounds overweight. At that point, you can sustain a big calorie deficit (I averaged a daily deficit of over 1800 calories/day for 8 weeks without a problem). However, when that body fat level starts to get closer to an "ideal" range, a high deficit can work against you. It is harder to maintain a smaller deficit consistently because of all the variables.

IMO, that's where higher-intensity training and more aggressive lifting (in moderate doses) need to play a larger role--at least 2x per week (but not more than 3). At the same time, counting exercise calories becomes less important.

Anyhow, looks like you have done great so far--keep up the good work.

chrisdavey

Great thread. Always enjoy reading your stuff. I was going to ask the same question re hybrid type strength circuits but already answered

I think I may have overestimated strength training cals but I generally underestimate my mma cardio training so it seems to balance out.

balfonso

bump for later.

meh have to go to work

izobel

Indeed you are always interesting reading, Azdak - thank you. I must admit I strength train two to three times a week and have for years but I never log the calories because I agree they are probably negligible. However I credit it for a complete absence of knee or hip injuries over years of jogging, mountain climbing, trail running, cycling, skiing etc. It builds so much protection around the joints, and then in daily life I can carry massive loads of shopping and lug huge suitcases because of the arm workouts. Weight training mightn't burn the calories of cardio but I really believe it is so so important especially as we age.

A question for you Azdak: Do we burn more calories at a higher perceived level of exertion? Sometimes I run and it feels like I am floating on air, so easy then other times it feels so hard and such a struggle right through the run - have I burnt more energy in the latter case? It certainly feels like a lot more effort involved.

Thanks again for your posts.

BoresEasily

Azdak, another enlightening post. Thank you yet again. I really enjoy reading your posts I usually learn a lot.

So the fat burning effects of HIIT have nothing to do with EPOC? Isn't that what everyone has been claiming for ages, the whole "afterburn" effect? What about straight intervals because those seem to work as well at moderate intensities so if it's not EPOC what do you suspect it is?

Reading your post makes me happy that I don't try like some to eat all of their suspected exercise calories back.

Azdak

Great thread. Always enjoy reading your stuff. I was going to ask the same question re hybrid type strength circuits but already answered

I think I may have overestimated strength training cals but I generally underestimate my mma cardio training so it seems to balance out.

You can use what "accounting" system that makes sense for you. Just keep in mind that all of these methods we use are artificial constructs to a great extent. In other words, we are trying to ascertain what is going on in our bodies--but your body keeps precise count of what is coming in and what is going out -- 24/7/365. So, whatever means you use to measure calorie intake and calorie expenditure must ultimately be tested against the Realities--scale, mirror, clothes, etc.......

Azdak

Indeed you are always interesting reading, Azdak - thank you. I must admit I strength train two to three times a week and have for years but I never log the calories because I agree they are probably negligible. However I credit it for a complete absence of knee or hip injuries over years of jogging, mountain climbing, trail running, cycling, skiing etc. It builds so much protection around the joints, and then in daily life I can carry massive loads of shopping and lug huge suitcases because of the arm workouts. Weight training mightn't burn the calories of cardio but I really believe it is so so important especially as we age.

A question for you Azdak: Do we burn more calories at a higher perceived level of exertion? Sometimes I run and it feels like I am floating on air, so easy then other times it feels so hard and such a struggle right through the run - have I burnt more energy in the latter case? It certainly feels like a lot more effort involved.

Thanks again for your posts.

Nothing I am saying is meant to, or should be taken as, anything negative about strength training. Strength training is ESSENTIAL for both the reasons you mention above and for it's contribution to permanent fat loss. There is a huge body of research that supports the idea that those who strength train and do cardio (and restrict calories, duh) lose more fat and lose it more permanently than cardio and diet alone.

The fact that strength training does not DIRECTLY burn a lot of visible calories during the actual workout is not significant and is NOT a reason to downplay resistance exercise. The primary benefits of strength training occur IN BETWEEN workouts, not necessarily during the workout itself.

OK, about perceived exertion: For the most part, the answer is "no". The energy cost of an activity is relatively fixed. For example, running at 6.0 mph (10:00 mile) requires about 35 milliliters of oxygen per kg of body weight per minute, or 10 METs. Within a small range, that energy demand is consistent for anyone doing the activity. (Exceptions being someone with certain medical conditions or who is obese). When the activity SEEMs harder, it's due to changes in your ability, rather than changes in the energy cost (and this calories burned) of the activity itself.

Azdak

Azdak, another enlightening post. Thank you yet again. I really enjoy reading your posts I usually learn a lot.

So the fat burning effects of HIIT have nothing to do with EPOC? Isn't that what everyone has been claiming for ages, the whole "afterburn" effect? What about straight intervals because those seem to work as well at moderate intensities so if it's not EPOC what do you suspect it is?

Reading your post makes me happy that I don't try like some to eat all of their suspected exercise calories back.

That's why research is done--to elaborate, delineate, quantify, or, in some cases, refute, "the claims". Sometimes it sucks to hear the truth.

Sometimes, we assume something is a "cause" of an effect, when in fact it is coincidental. Lactic acid accumulation was once considered to be a primary cause of muscle fatigue and even muscle soreness. In the 1920s, a couple of guys won a Noble Prize for, among other things, outlining the theory of "oxygen debt". With the advent of radioactive tracer studies on lactate around 1980, that theory was disproved --which, BTW, is the origin of the term "EPOC". EPOC was coined by George Brooks as a replacement for what he called the "obsolete" term of oxygen debt.

But I digress. From what I have read (and I know others on this forum --Banks for one--read a lot of literature as well, so hopefully they will correct me if I come up short), the cause is not fully known, but it is suspected that it might have something to do with increased catecholamine release during high-intensity exercise. It could also be that there is a metabolic component that is not measurable via indirect calorimetry (measuring oxygen uptake). Right now, we know something is happening --the comparison results are pretty strong-- we just don't understand why it is occurring.

Keep in mind also that individual results depend on the past history of the individual. Some people get results with HIIT simply because it represents a higher total outlay of calories that what they have done before.

We also have to look at the long-term effects of HIIT and other high-intensity modalities. Do the advantages we see persist over time? Do they level off? Are there problems with long-term adherence?

For now, I say the same thing I have always recommended: the average person will get the best results long-term by following a balanced program that includes endurance exercise, higher-intensity training (intervals, etc) and resistance exercise.

Chickabittie

For now, I say the same thing I have always recommended: the average person will get the best results long-term by following a balanced program that includes endurance exercise, higher-intensity training (intervals, etc) and resistance exercise.

Yes, follow a well rounded program. Mix it up! Don't let your workouts get stale.