This is a GREAT question asked by one of my clients. They have a strict daily routine/schedule and have been consistent with exercise for the past 2 years.
So, what's the right answer?
Too Long, Didn’t Read (TLDR) Summary:
Running is commonly (and not incorrectly) understood as the best calorie burner per time.
A skim of more current, peer-reviewed research reveals that it’s probably better to base your exercise on HR intensity instead of a specific type of exercise.
Calories are not bad, you need to eat to fuel your progress.
Every Body Is Different
Read that again. “Every body is different.” Not just that everybody is different, that’s true too, but your body is different than mine. We may do the same types of exercise and have similar biometrics, but our bodies are different.
While there are some general rules and data simplifications that can help guide your fitness decision-making, remember that what works best for you may not be what works best for everyone.
Also, exercise physiology is historically not great at using generalizable populations–so the results have to be taken as “guidelines” instead of “the code” (yes, Captain Barbosa, they’re more like guidelines).
What does the internet say about the best exercises for calorie burn?
Not that you can’t look this up yourself, but here are a couple results I found with a search “best exercise for caloric burn.”
Running is the best “burn” for your buck
Healthline has an article that says if you have an hour to exercise, running is your best bet to burn the most calories per hour. They don’t say where they got this data (at least where I could find it at a cursory glance).
There you have it, running burns an average of 106 calories more per hour than the second-best option per the three body weights listed.
That’s pretty good. If you’re close to that 155 lbs category, you’re burning around 130 calories per 10 minutes.
The problem with this–which Healthline acknowledges–is that you have to account for muscle mass, intensity, and experience. If you have low muscle mass, you might benefit from pairing strength training with running so you can maximize calorie burn (more muscles working more requires more calories). If you have an injury-rich history, you might be apprehensive about jumping into a moderate-to-high-intensity running routine and therefore not reach those calorie-burning benchmarks.
Then there’s experience level with running. Running is kinda the worst at first–it’s just unnatural until it’s not. You may have to start with run/walk intervals. Those are awesome for getting into running but definitely won’t meet the high standards for calorie expenditure listed in the graph.
Should I run more based on this research?
Admittedly, I love running. It’s my exercise and sanity-preserver of choice. However, if you need to maximize calorie burn per time of exercise and are either not familiar with running, just starting a strength program, or concerned about injury you probably shouldn’t count on running as your number 1 calorie burning method.
That doesn’t mean running won’t ever work for you! You’ll just want to talk to your trainer, physical therapist, doctor, chiropractor, or whoever else is guiding your fitness journey, first.
“Usually, the more intense an exercise routine is, the more calories it burns.” - Medical News Today
This piece from MedicalNewsToday.com starts with a smart overarching theme–intensity of exercise is directly related to calorie burn (*usually*).
Running is the “calorie king” once again (even at 30 minutes)
This article used a calorie calculator from the Calorie Control Council to estimate caloric expenditure for different activities for a given body weight. Once again, running came out on top of the list for best calorie expenditure over a given time.
They break each exercise down into 30 minutes sessions and evaluate from there–which I appreciate, because that’s more applicable to the general population. It’s important to note that the calorie calculator is based on “moderate” intensity exercise.
How do I find “moderate intensity” for myself?
This is a tricky thing to measure. There’s the subjective but reliable Rate of Perceived Exertion scale (see below, thanks for the graphic, Cleveland Clinic) You can also use a heart rate scale of sorts to find some basic heart rate zones that correlate with intensity levels.
The easiest and, I’d say, least reliable way to find your heart rate (HR) zones is to take 220 and subtract your age, then use percentages. This doesn’t take into consideration your specific HR at rest, though, so the Karvonen formula is a better starting point. Here’s a calculator that uses Karvonen and pops out a list of percentages for you!
What percentage of HR is moderate intensity?
The CDC says that moderate intensity exercise should put your HR between 64% and 76% of your maximum HR.
What if I don’t have a heart rate tracker?
Fine! You can either measure your own heart rate (less reliable, I think, because you’re likely still moving and trying to look at a clock and trying to count beats–it’s a lot at the same time) or you can use the previously mentioned Rate of Perceived Exertion (RPE) scale!
As a general rule, for moderate intensity exercise, you’ll want to be in that green zone. And yes, the RPE scale is called the Borg scale because Mr. Borg developed it. He used the numbers 6-20 because those generally correlate with a HR ten times the number (15 = 150bpm).
The modified Borg Scale is a little easier to use. It’s 0-10 and you don’t have to explain to people that their age may affect the reliability of HR correlations with the traditional Borg Scale.
What does the research say about types of exercise and calorie burn?
You’ll be relieved to know that some research found a direct relationship between intensity level (aka HR zone) and caloric expenditure.
HIIT Wins vs Running In Recent Research
An article published in 2015 for the Journal of Strength and Conditioning Research found that HIIT training (defined as using HRS, or hydraulic resistance system) at 20 seconds activity, 40 seconds rest interval was the best for a 30-minute exercise session aimed at calorie burn.
The researchers compared this 20:40 HIIT program, resistance training at 75% of one-rep max, treadmill running at 70% HR max, and stationary cycling at 70% of HR max. The study was performed using all male participants around 25 years old who were “recreationally active.”
Does this mean running isn’t the best way to burn calories?
I think the main takeaway from this is if you want to burn the most calories per time you should focus on HR intensity.
The research which says HIIT is better than other options had a specific population that may not be very applicable to every population. This means you have to take your specific past, present, and future into account when determining the best exercises for you
A personal trainer is uniquely trained in doing just that!
After reading that last paragraph you might wonder if the population limitations make that research low quality. I would say that they don’t. However, the recent movement to include more generalizable populations in exercise research will help everyone apply research to their individual situation.
After all the research, what should I do?
I hate that answer, but it fits here. You should work with a personal trainer (Me! Pick me!) to determine the best, safest, most sustainable/enjoyable exercise type that you can perform at moderate intensity.
What if you don’t like the resultant exercise type?
That’s fine! It’s precisely why goal-setting is important. Is your goal to find an exercise activity you enjoy? Or is your goal to burn more calories over the next few months? Let your goals guide you.
Final Thoughts On Calories and Exercise
Running, especially trail running, happens to be my favorite method of exercise. I burn a lot of calories because I enjoy what I’m doing and have a tendency to lean more into the moderate/vigorous HR zones.
This isn’t a brag, if anything it’s a confession!
Calories aren’t bad. Because I run and want to keep running, and running burns a lot of calories at even moderate intensity, I need to consume more calories than normal. If you go into a caloric deficit by burning or expending more calories than you consume, you may lose weight.
BUT you run the risk of hindering your body’s ability to recover and adapt to applied strain! Once again, it all comes down to your goals and having someone you trust to talk to about your goals and progress.