Walking or Biking: Which Burns More Calories?

Q: I walk to work and it takes about an hour to cover three-and-a-half miles. I would rather start cycling to get to work faster, but I don't want to burn fewer calories. Will I burn the same number of calories by walking or biking the same distance?

A: How many calories you burn during exercise depends on two things: The intensity of exercise, and the total number of minutes you are moving. You can find out about how many calories you burn during each activity with the easy-to-use MSN Health & Fitness Interactive Tool.

Here’s a step-by-step guide to using the tool to find out which commute—walking or cycling—burns more calories:

1. First, enter your current weight. This is important to include because how heavy you are affects your energy expenditure. A 110-pound person will burn far fewer calories walking for 30 minutes than a 175-pound person. You don't mention how much you weigh, but for the sake of comparison, I'll enter 160 pounds.

2. Next, enter the activity duration—in your case, one hour.

3. Then choose your activity from the drop-down list. In this case, scroll down to enter "Walking." Next, indicate the type of walking under "Choose exercise." Your walking speed of 3.5 miles per hour is considered a medium pace, so click on that.

4. After pressing “Click to calculate,” you'll see your results suggest that you burn about 240 calories in an hour of walking to work.

Now to calculate the cycling calories, follow the same steps, but this time for step 2, you'll enter the length of time it takes you to cycle to work. You don't mention how long, but I'll enter 20 minutes, estimating a pace of 10 to 12 m.p.h. (Keep in mind if you live in a very hilly area it could be slower and take longer; if you have lots of stop lights along the way, you could be adding more time to your commute that's not riding time.)

After entering "20 minutes" for time, you'll follow these steps:

• For "Choose activity," select "Bicycling."
• For "Choose exercise," select 10-12 mph (light).
• After pressing "Click to recalculate," you get an estimate of 182 calories.

So the answer to your question is that you'll burn an estimated 60 fewer calories by riding a bike instead of walking—but you're likely to save yourself about half an hour of time each way.

Of course, how hard you work during any activity affects how many calories you burn. If you boosted the pace of your walk to 4 mph, you could get to work about 10 minutes sooner, while burning around the same number of calories. If you jogged instead, with a somewhat slow pace of 10 minutes per mile, you could get to work in 35 minutes, burn around 82 more calories than walking in the process. (Of course, this is a sweatier travel method, so you might need to shower once you get to work!)

No matter how you choose to get to work, you're on the right track. So many people complain that they don't have any time to exercise, but if all they did was exercise as they commute, they'd make a huge difference in their health and weight over time.

Another bonus: Since cycling will get you there much faster and save you time, this option would allow you to sleep in a bit longer in the morning compared to walking. Perhaps being this little bit more rested would give you more energy to work out a little harder or longer on the way home from work.

Or, you could lengthen your journey a bit with a few extra laps, especially if you ride through a park along the way. Instead of getting there 35 minutes sooner, try to arrive 15 or 20 minutes sooner, so you can potentially burn more calories from the ride. Or mix up both approaches. Adding variety to your exercising will make you more likely to stick with it.

Congratulations on integrating daily physical activity into your life!

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Martica is a Manhattan-based exercise physiologist and nutritionist and an award-winning fitness instructor. She has written for a variety of publications including Self , Health , Prevention , The New York Times and others. Martica is the author of seven books, including her latest, - Cross-Training for Dummies . (Read her full bio.)