Rucking calorie burn
Exactly how many calories your ruck burns.
Post summary
The ultimate guide to rucking calorie burn.
We’ve ran data from new research on rucking and calorie burn to help you calculate exactly how many calories your ruck burns.
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Audio/podcast version
The post
On Monday, we answered the most common questions about rucking (read Rucking 101 here). One question dealt with calorie burn.
“How many calories did my ruck burn?” is a question that fills my inbox.
People message me details like their body weight, ruck weight, and pace and ask if I can give them their exact calorie burn number, like I’m a human FitBit.
I get it. We want to measure a workout’s impact so we can make reasonable comparisons between other workouts.
But Monday’s post didn’t get into specifics about rucking calorie burn. Instead, it gave a wide range of estimates and raised questions about why we care about burning calories in the first place.
Today, we’re getting into specifics and helping you calculate exactly how many calories you burn on a given ruck.
Let’s roll …
The new science of rucking calorie burn
Section summary: A new study fixes prior issues with the military’s rucking calorie burn formulas. We spoke to the lead researcher and got the numbers. The study also included a higher ratio of women, making the data more universal.
To get the best new estimates on rucking and calorie burn, I spoke with David Looney.
David is a mathematical physiologist who conducts research with the US Army Research Institute of Environmental Medicine. He explained:
“My research develops decision aid algorithms and other predictive methods for ensuring that soldiers and athletes and others that have to perform in the most extreme conditions can do so to the best of their abilities. Maximizing human performance in any conditions—hot, cold, while carrying heavy loads, whatever people are doing, I'm trying to help them out.”
Rucking is the most important physical act of soldiers, so the US Army Research Institute of Environmental Medicine has been examining it for years.
Calculating calorie burn from any activity isn’t easy.
But rucking adds even more complications to the mix. And you’ve probably experienced this yourself. Your fitness watch probably doesn’t have rucking as an option. And even if it does, it’s some giant degree of wrong.
Go deeper: Read about the many problems with fitness watch calorie burn and strain calculators here.
Calculating rucking calorie burn is challenging because:
It’s a rather understudied form of exercise.
It mixes strength and cardio.
It includes many factors that impact calorie burn. For example, the weight in your ruck, the terrain you’re rucking on, and more.
It also has a muscular effect. It will lead you to burn more fat and build or maintain muscle, and your improved body composition will likely have longer-term calorie-burning effects1.
Still, scientists have come up with all sorts of ways to make reasonable assessments. For example:
You can use METs and the Compendium of Physical Activities.
You can use various equations developed by the military (Pandolf or Santee equation).
But David had conducted some previous work on the topic and found that our current equations could be better. For example, one of his studies discovered that the Pandolf equation underestimates calorie burn.
“We knew that the Paldolf equation needed to get fixed—there were just some inherent issues with it,” he told me.
The new rucking calorie burn study
Enter David’s new study2. It dove deeply into rucking and calorie burn—and the results can help us calculate our rucking calorie burn.
He took a group of soldiers and had them ruck in a lab using different loads and at different speeds.3 They rucked using 22, 44, and 66 percent of their body weight at paces ranging from 1 mile an hour to roughly 4.5 miles an hour.
As they walked, they had a device strapped to their mouth to measure their oxygen uptake and carbon dioxide production (like a VO2 test). That told the scientists how many calories the ruckers were burning.
David said:
All the data is derived from that group of soldiers. And then we tested it out and validated it against data that was collected in different soldiers and different populations, just to prove this wasn't a one trick pony. So this finding wasn’t isolated to our lab.
Importantly, David’s study included more women than previous studies.
Military research has traditionally focused on men, but more women are now entering the military. This means data from older rucking studies may not apply to all people.
David wrote in the study:
The current study represents a step in the right direction for female representation in exercise sciences, with the combined sample including more female participants than previous military load carriage metabolic modeling studies as well as a slightly higher percentage of females than the modern US military active-duty force.
(More on this topic in a future post on Two Percent … stay tuned).
Below, we’re using data from David’s new model to calculate how many calories your ruck burns.
I think the model does a reasonable job estimating calorie burn—it’s likely the best existing estimate of rucking calorie burn.
How many calories rucking burns: the numbers
Section summary: These graphs reveal how many calories your ruck burns based on your body weight, the weight you have in the ruck, the terrain, and how fast you’re rucking.