Chapter 1: Understanding Energy Efficiency in Movement

When it comes to conserving energy during travel, the quickest option isn't always the most effective one.

Photo by Mārtiņš Zemlickis on Unsplash

Every summer, I embark on backpacking trips, typically covering around 15 miles (24 km) daily over several days. My goal is to traverse from one remote valley to another while carrying all necessary supplies. The fewer calories I expend, the less food I need to bring along. Hence, understanding energy efficiency becomes crucial: Is it better to walk or run?

The Research Evidence

Extensive academic studies on locomotion efficiency span nearly a century. One notable paper from 1976 employed “high-speed” film to analyze limb movement and calculate total energy expenditure during movement. The findings indicate that walking is generally more efficient at standard speeds, but this efficiency diminishes compared to running as speed increases.

Figure 1: A comparative analysis of walking and running efficiency at various speeds. Running tends to consume more calories per mile than walking.

Recent studies reaffirm these findings, suggesting that walking is most efficient at about 3.5 MPH (5.6 KPH), while runners exhibit relatively consistent energy consumption, which gradually decreases with speed. Cumulatively, research shows that long-distance runners expend approximately 30–50% more calories per mile than an average walker. Therefore, if your objective is to conserve energy and you're not in a rush, walking is the better option.

To substantiate these academic insights, I analyzed my personal fitness data. Over the past few years, my fitness tracker has recorded numerous walking and running activities, allowing me to calculate the active calories burned per mile.

Figure 2: Average active calories burned per mile based on logged walking and running activities. I burn slightly over 100 calories per mile while running, compared to about 75 calories per mile when walking.

While I don't see consistent numbers each time—perhaps due to varying conditions or external factors—my average suggests I burn roughly 40% more calories per mile running than walking, aligning with the research findings.

I conducted a short test where I both walked and ran on a designated course. As expected, walking proved to be the more energy-efficient choice.

Figure 3: Direct comparison of calories burned during a two-mile walk versus a run, showing significantly fewer calories burned while walking.

Whether one relies on academic literature, personal fitness data, or a head-to-head comparison, all methods yield the same conclusion: Walking is more energy-efficient than running. The reasons for this increased efficiency are multifaceted, but the fundamental idea is straightforward: Walkers maintain contact with the ground, while runners expend more energy launching themselves into the air with each stride.

Chapter 2: Discrepancies in Caloric Tracking

So why do fitness trackers often report similar calorie counts for walking and running? Most likely, it's due to the devices measuring total calories rather than active calories.

Humans burn a baseline amount of energy for essential functions, such as maintaining body temperature, digesting food, and cell repair. This energy expenditure occurs regardless of activity level, whether exercising or resting. Garmin, a leading fitness tracker brand, refers to this energy as resting calories.

At my current age and weight, I require about 2,000 resting calories daily, which breaks down to around 1.4 calories per minute just to sustain basic bodily functions.

Resting calories do not reflect exercise intensity or quality. Whether lifting weights or participating in a spin class, my focus is on the active calories consumed.

In my experience, most fitness devices, including watches, treadmills, and rowing machines, prominently display total calories (resting + active). This likely enhances perceived performance. After all, a treadmill that indicates 400 calories burned might attract more users than one that reports only 300 active calories.

Total calories are certainly important for overall health, as they provide insight into our daily energy expenditure. However, when evaluating workout effectiveness, active calories are far more telling. Longer, lower-intensity workouts, like walking, can accumulate resting calories, leading to inflated calorie counts that misrepresent the intensity of the workout.

Figure 4: Comparison of calorie counts for an 8-mile walk versus run. Both activities reported nearly identical total calorie counts, yet the running session lasted only one hour while the walking session took nearly three hours, resulting in significantly fewer active calories burned during the walk.

In my experience, most devices default to reporting total calories. This includes my Garmin watch and various fitness apps. However, I usually can access the active calorie count in the activity summaries.

Don't let your fitness devices mislead you: Understand the difference between total and active calories. The evidence consistently shows that walking is more energy-efficient than running.

Why Choose Running?

If walking is indeed more efficient than running, why do people opt to run? The answer isn't solely about speed. While I can run more than three times the distance in an hour compared to walking, if I were truly in a rush, driving or biking would be more sensible choices.

For me, running serves a purpose: it is a high-intensity activity that challenges my body and ultimately contributes to my overall strength and fitness. This intensity isn't always directly related to calorie expenditure; a short, intense workout might burn fewer calories than a longer, moderate one, yet both styles are essential for building strength and endurance.

Garmin fitness trackers quantify fitness improvements beyond calories, using a metric called Excess Post Oxygen Consumption Training Load. I affectionately refer to these metrics as “training beans.”

To prepare for demanding multi-day backpacking trips, I focus on high-intensity activities that yield significant "beans."

Figure 5: Box plots illustrating typical training beans earned per hour across various workouts. Originally published in "Why I Keep Running When I Don’t Enjoy It."

I engage in diverse athletic activities weekly, meticulously tracking my performance with my Garmin watch. Based on my training bean metric, I find running to be the most effective workout for enhancing my fitness. In essence, I run to improve my walking abilities.

Chapter 3: Comparing Walking and Running to Other Modes of Transport

Assessing the efficiency of various travel methods has become a personal interest. While walking emerges as the most efficient form of movement on foot, bicycles remain the top choice for overall transportation, as revealed in my previous analyses. Interestingly, all forms of self-powered transport outperform automobiles.

Figure 6: Efficiency comparison among different modes of transportation. Note: There are nuances in directly comparing various energy sources (for instance, electricity generation is less efficient than gasoline) and vehicle types.

The goal of this analysis is to provide insight and help individuals choose the best transportation method for each scenario. If energy conservation is your priority, walking is your most efficient option. For my backpacking endeavors, it is far more beneficial to walk for seven hours than to run for three. Ultimately, it's about the journey; I want to take the time to appreciate my surroundings.

Photo of the author approximately four hours into a three-day camping excursion, already pondering over the weight of his pack.

I continually seek ways to enhance my life, particularly through cycling and sustainable energy practices, sharing insights that may benefit others. My background includes technical training expertise, a Ph.D. in Biochemistry, and certification as a Project Management Professional (PMP).

In the video "Walking Vs. Running: Which Is Best?," the discussion focuses on the comparative benefits and drawbacks of both activities, providing further context to the energy efficiency debate.

The video "The Science of Run Walk Run Energy: Does Ratio Matter? Maybe!" delves into the energy dynamics of different running and walking strategies, enhancing our understanding of efficient movement.