Does stair climbing bulk up your legs?

Q: I started walking up 66 flights of stairs during my lunch break to help lose weight. I’m also trying to limit my diet to 1,500 calories per day and doing 30 minutes of additional cardio in the evenings. Some co-workers have warned me against the stair climbing, warning that it will make my legs bigger, is this true?

A: Absolutely not. Many people who have not studied exercise physiology and biomechanics have misconceptions about the effects of different types of exercise.

How muscular your legs get is genetically determined. The only way to increase the size of the muscles in your lower body is to do progressive, intense strength training (read: lift increasingly heavy weights over time) along with eating more to fuel muscle growth. But even body builders who work super hard to try to build muscle find it difficult (think of the beefy guy with big muscles on top, but scrawny legs).

While someone who has never climbed a stair may experience some slight increase in muscle mass from lifting their own body weight, it’s highly unlikely that stair climbing provides enough resistance to stimulate muscle growth if you’re used to doing it. Even if it did, the gain would be minimal.

Total calorie burn

What stair-climbing does do for you is burn lots of calories. And it’s that mega calorie burn that will dramatically contribute to your weight-loss efforts. If you count the total minutes it takes you to climb those 66 flights, you can estimate the number of calories burned.

The Compendium of Physical Activities is a research-validated tool to help estimate the intensity, and therefore calories burned, during a variety of activities. The baseline measure is coined 1 MET (or metabolic equivalent). One MET is meant to represent the intensity level of a person while sitting quietly. As the body moves with more intensity or speed, the MET level, or effort required, goes up.

Moderate-intensity activity, or working at an effort that is around 45 percent to 62 percent of maximum oxygen capacity (VO2max), is said to be between 5.4 and 7.5 METs. Hard or vigorous-intensity activity, or working at an effort that is around 63 to 85 percent of maximum oxygen capacity (VO2max), is said to be between 7.6 and 10.2 METs. Normal walking up stairs (without carrying a load) is estimated to be 9 METs.

Researchers then use this MET level to estimate the calories burned per minute, or energy expenditure of the activity. One MET is the equivalent to burning one calorie per kilogram of body weight per hour. To calculate calorie burn, you would first convert your weight to kilograms. (Just divide by 2.2). So, a person who weighs 165 pounds, for example, is 75 kg. That person would burn around 75 calories per hour at rest (based on the rate of 1 MET while at rest). And walking up stairs at 9 METs would mean that person would burn around 75 kg x 9 METs, or 675 calories per hour.

Keep in mind that you would burn less walking down the stairs, as the intensity is lower. So if you weigh 165 pounds, or 75 kg, and walked up and down the stairs for 20 minutes, you might burn 225 calories from walking up only. If you walked down for 10 minutes of that time it would be slightly fewer calories. Keep in mind that calorie burns are always estimates, so don’t try to get too exact.

A high-intensity workout

Any way you slice it, though, walking up stairs is a great workout, and you’ll burn more calories than you would walking on flat ground for the same amount of time. You can find out more about these calculations in the new federal Physical Activity Guidelines Committee Report, part D.

A big bonus you get from trampling up the staircase is higher intensity. Stair-climbing is an especially vigorous form of cardiovascular exercise. And recent physical activity guidelines from the American College of Sports Medicine and the American Heart Association have emphasized the important of working at vigorous, as well as moderate, intensity effort levels. An added benefit is that stair climbing is low-impact, so you can work hard without a lot of pounding on your joints.

That’s not to say that stair-climbing is without stress to the joints. In fact, walking DOWN steps can be very stressful to the knees. That’s one reason why step-aerobics class, if taught according to established safety guidelines, involves no choreography where the participant steps forward off of the step. The step-aerobics moves should only include moving sideways up and down from the step, or stepping backward off the step (so the heel steps off the step and lands on the floor first, rather than the toes). Needless to say, running down forward from a step is even more stressful to the knees.

So, to keep your stair-climbing workout safe, walk or run up the steps (and if you run, watch your feet and hold on to handrails if needed), and walk down slowly. If you find that your knees bother you, then consider walking down sideways. This will clearly slow down your pace, but since the upward journey is so intense, you can view the return down as a recovery interval where you go slower and let your heart rate, or effort level, lower.

Keep on climbing!

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Martica Heaner, Ph.D., M.A., M.Ed., is a Manhattan-based exercise physiologist and nutritionist, and an award-winning fitness instructor and health writer. She has a Ph.D. in behavioral nutrition and physical activity from Columbia University, and is also a NASM-certified personal trainer. She has written hundreds of articles for publications such as Self , Health , Prevention , The New York Times and others. Martica is the author of eight books, including her latest, Cross-Training for Dummies. (Read her full bio.)