By Alicia Richmond

---

Whether shaking off the holds of winter in spring, escaping the summer heat, or enjoying the fabulous fall foliage, exploring Utah’s outdoor beauty is a popular pastime. 

And almost as popular as the incredible hiking trails and breathtaking outdoor views, is tracking and chronicling those excursions. After all, did it even happen in the year 2026 if data wasn’t gathered or it can’t be shared socially?

But how accurate are those energy expenditure prediction equations used by various devices and fitness apps? 

This is the question Utah State University graduate student Merrill Ward — with the help of Kinesiology and Health Science professor Dale Wagner — decided to explore for his master’s capstone research project. 

“I had this idea to go out and do research that involved measuring energy usage and whatnot,” says Ward, who recently graduated with a master’s degree in exercise science. “The KHS department happens to have a K5 portable metabolic oxygen monitoring system, so it seemed like a perfect opportunity.”

Currently, there are several oxygen prediction equations that can estimate energy expenditure or oxygen consumption while walking on a treadmill at various speeds and grades. However, Ward knew these equations might not be as accurate as actually measuring a person’s rates as they hike on a moderate trail while wearing a daypack. 

The K5 portable gas analysis system Ward used allows a research participant to wear a specifically designed face mask that measures respiratory and metabolic responses in actual hiking conditions, rather than being restricted on a treadmill. The system measures the gases a person breathes in and out and tracks oxygen consumption, carbon dioxide production, respiratory exchange ratio, and overall energy expenditure. 

“Merrill’s goal was to see how accurate these equations are when applied to real-life hiking, varying grades, self-selected walking speeds, and carrying a daypack,” Wagner explains. “To evaluate the accuracy of the prediction equations, he asked avid hikers to wear the mask while walking up and down the Logan Canyon Wind Cave Trail.”

In essence, Ward and Wagner moved their exercise physiology lab outdoors — choosing the Wind Cave Trail because of the four-mile round-trip distance, the elevation of more than 5,000 feet, and its variable grade that climbs 1,000 feet over nearly two miles.

The study consisted of 15 participants — 10 male and 5 female — who had their oxygen consumption measured by the portable metabolic unit while hiking both up and down the Wind Caves trail. 

“Overall, the equations predicted reasonably well on the uphill section of the trail, but they did not perform as well on the downhill section,” Ward shared.

The data collected from Ward’s research study can be used to help measure the calories expended when a person exercises on varying terrains and over different distances. Overall, Wagner was impressed with Ward’s innovative approach. 

Merrill was independent on this research project,” Wagner says. “He analyzed different variables, not just uphill and downhill, and he looked at different sections of the Wind Caves — like a slightly easier grade and the steeper grades. I was just thinking of the entire uphill and downhill; I never even considered separating the trail into various segments by gradient. This was all his idea.”

If a person is going on a hike and wears a smartwatch with an app that measure calories burned, the data collection from Ward’s study can be used to assist with these equations and help improve accuracy levels. 

“I typically work with master’s students on research projects. It’s a valuable tool for them to learn how to submit a proposal and conduct pilot testing and data collection,” Wagner says. “Merrill now knows how to use a K5 machine for portable gas analysis, which is a useful skill to add on a resume in our field — especially in a competitive job market.”

As an R1 institution Utah State offers significant opportunities for students to participate in research projects — something many seek out as part of their experiential learning experience.

“This research project was a huge opportunity for me,” exclaims Ward, who is now a doctoral student in the Emma Eccles Jones College of Education, Health, and Human Sciences. “It was very rewarding to work with an expert in my field. I was excited to approach Dr. Wagner to be my mentor for my capstone project. I have learned a lot that I would not have learned otherwise.”