Nav: Home

Good news! You're likely burning more calories than you thought when you're walking

March 15, 2016

Walking is the most common exercise, and many walkers like to count how many calories are burned.

Little known, however, is that the leading standardized equations used to predict or estimate walking energy expenditure -- the number of calories burned -- assume that one size fits all. They've been in place for close to half a century and were based on data from a limited number of people.

A new study at Southern Methodist University, Dallas, found that under firm, level ground conditions, the leading standards are relatively inaccurate and have significant bias. The standards predicted too few calories burned in 97 percent of the cases researchers examined, said SMU physiologist Lindsay Ludlow.

A new standardized equation developed by SMU scientists is about four times more accurate for adults and kids together, and about two to three times more accurate for adults only, Ludlow said.

"Our new equation is formulated to apply regardless of the height, weight and speed of the walker," said Ludlow, a researcher in the SMU Locomotor Laboratory of biomechanics expert Peter Weyand. "And it's appreciably more accurate."

Ludlow and her colleagues report the new equation in the Journal of Applied Physiology, "Energy expenditure during level human walking: seeking a simple and accurate predictive solution." The article is published in the March 1, 2016 issue, and available online at http://jap.physiology.org/content/120/5/481.long.

"The economy of level walking is a lot like shipping packages - there is an economy of scale," said Weyand, a co-author on the paper. "Big people get better gas mileage when fuel economy is expressed on a per-pound basis."

The SMU equation predicts the calories burned as a person walks on a firm, level surface. Ongoing research is expanding the algorithm to predict the calories burned while walking up- and downhill, and while carrying loads, Ludlow said.

SMU's research is funded by the U.S. Department of Defense Medical and Materiel Command. The grant is part of a larger DOD effort to develop load-carriage decision-aid tools to assist foot soldiers.

The research comes at a time when greater accuracy combined with mobile technology, such as wearable sensors like Fitbit, is increasingly being used in real time to monitor the body's status. The researchers note that some devices use the old standardized equations, while others use a different method to estimate the calories burned.

New equation considers different-sized people

To provide a comprehensive test of the leading standards, SMU researchers compiled a database using the extensive walking metabolism data available in the existing scientific literature to evaluate the leading equations for walking on level ground.

"The SMU approach improves upon the existing standards by including different-sized individuals and drawing on a larger database for equation formulation," Weyand said.

The new equation achieves greater accuracy by better incorporating the influence of body size, and by specifically incorporating the influence of height on gait mechanics. Specifically:
  • Bigger people burn fewer calories on a per pound basis of their body weight to walk at a given speed or to cover a fixed distance;

  • The older standardized equations don't account for size differences well, assuming roughly that one size fits all.

Accuracy of standardized equations had not previously undergone comprehensive evaluation

The exact dates are a bit murky, but the leading standardized equations, known by their shorthand as the "ACSM" and "Pandolf" equations, were developed about 40 years ago for the American College of Sports Medicine and for the military, Ludlow said.

The Pandolf method, for example, draws on walking metabolism data from six U.S. soldiers, she said. Both the Pandolf and ACSM equations were developed on a small number of adult males of average height.

The new more accurate equation will prove useful. Predicting energy expenditure is common in many fields, including those focused on health, weight loss, exercise, military and defense, and professional and amateur physical training.

"Burning calories is of major importance to health, fitness and the body's physiological status," Weyand said. "But it hasn't been really clear just how accurate the existing standards are under level conditions because previous assessments by other researchers were more limited in scope."

Energy expenditure estimates could assist with monitoring the body's physiological status

Accurate estimations of the rate at which calories are burned could potentially help predict a person's aerobic power and likelihood for executing a task, such as training for an athletic competition or carrying out a military objective.

In general, the new metabolic estimates can be combined with other physiological signals such as body heat, core temperature and heart rate to improve predictions of fatigue, overheating, dehydration, the aerobic power available, and whether a person can sustain a given intensity of exercise.

Military seeks solutions to overburdened soldier problem

The military has a major interest in more accurate techniques to help address their problem of over-burdened soldiers.

"These soldiers carry incredible loads -- up to 150 pounds, but they often need to be mobile to successfully carry out their missions," said Weyand, a professor of Applied Physiology and Wellness in the SMU Simmons School of Education.

Accurately predicting how many calories a person expends while walking could supply information that can help soldiers avoid thermal stress and fatigue in the field, especially troops deployed to challenging environments.

"Soldiers incur a variety of physiological and musculoskeletal stresses in the field," Weyand said. "Our metabolic modeling work is part of a broader effort to provide the Department of Defense with quantitative tools to help soldiers."
-end-
SMUResearch.com on Twitter, http://twitter.com/smuresearch.

For more information, http://www.smuresearch.com.

SMU is a nationally ranked private university in Dallas founded 100 years ago. Today, SMU enrolls nearly 11,000 students who benefit from the academic opportunities and international reach of seven degree-granting schools. For more information see http://www.smu.edu.

SMU has an uplink facility located on campus for live TV, radio, or online interviews. To speak with an SMU expert or book an SMU guest in the studio, call SMU News & Communications at 214-768-7664.

Southern Methodist University

Related Calories Articles:

Calories in popular UK restaurant chain dishes can be 'shockingly high' warn experts
The calorie content of popular starters, sides and desserts served in UK restaurant chains is too high and only a minority meet public health recommendations, finds a University of Liverpool study published in BMJ Open.
Monkeys like alcohol at low concentrations, but probably not due to the calories
Fruit-eating monkeys show a preference for concentrations of alcohol found in fermenting fruit, but do not seem to use alcohol as a source of supplementary calories, according to a study by researchers from Linköping University, Sweden, and the Universidad Veracruzana, Mexico.
Pregnant women with obesity may not require additional calories for healthy pregnancies
Guidelines for weight gain and caloric intake during pregnancy are not tailored to women with obesity, 2/3 of whom gain excessive weight during pregnancy that poses a risk to mother and child.
Exercising while restricting calories could be bad for bone health
UNC School of Medicine's Maya Styner, MD, led research showing that the combination of cutting calories and exercising can make bones smaller and more fragile in animals, whereas exercise on a full-calorie diet has a positive impact on bone health.
Even in svelte adults, cutting about 300 calories daily protects the heart
In adults already at a healthy weight or carrying just a few extra pounds, cutting around 300 calories a day significantly improved already good levels of cholesterol, blood pressure, blood sugar and other markers.
'Traffic light' food labels reduce calories purchased in hospital cafeteria
A new study by Massachusetts General Hospital shows that labeling food choices in a hospital cafeteria with simple 'traffic-light' symbols indicating their relative health value was associated with a reduction in calories purchased by employees.
Children and teens who drink low-calorie sweetened beverages do not save calories
US children and teens who consumed low-calorie or zero-calorie sweetened beverages took in about 200 extra calories on a given day compared to those who drank water, and they took in about the same number of calories as youth who consumed sugary beverages, according to a new study.
Not drinking water associated with consuming more calories from sugary drinks
This study examined how drinking water was associated with the amount of calories children, adolescents and young adults consume from sugar-sweetened beverages, including sodas, fruit drinks and sports drinks.
Diets consisting of fewer calories improve cell performance
Animal experiments have shown that caloric restriction causes cellular changes that can prevent diseases, the subject of a session at FAPESP Week London.
Calories in popular restaurant chain meals 'excessive' warn experts
The calorie content of popular main meals served in UK and international restaurant chains is excessive and only a minority meet public health recommendations, finds a University of Liverpool study published in the Christmas issue of The BMJ.
More Calories News and Calories Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.