The Truth is in the Metabolic Armband

If you're like me, you've probably done some sort of physical activity and thought to yourself afterward "gee, that must've burned a whole bunch of calories!" But how many? For a class last semester I got to wear a metabolic armband for 24 hours that tracked my calorie output (as well as my sleep quality, how many minutes of moderate and vigorous activity I did, and the number of steps I took). How does it do this? By strapping the band onto your upper arm, it measures "galvanic skin response" to see how much you sweat in addition to skin temperature, the rate at which heat is being dissipated, and, via the accelerometer, how much you're moving. I was so excited to get to use the armband but I had a hard time deciding which physical activity I wanted to do on my one day; it ended up raining so an hour and a half of hot yoga won out over other options. Still, I was itching to try out other activities.

Last week I was able to borrow the armband for a whole week for just this purpose. I had a couple of activities I knew I wanted to try and then I talked with friends and followers to see what activities they've been wondering about. When I could, I compared my armband results from those that either the machine indicated, a website calculated, or the instructor of the class estimated to see how accurate these tools are compared with the armband (which claims to be the most accurate armband on the market).

Here's what the Body Media website that the armband syncs to knew about me going into it: my gender (female), my hand (right), my height (5'3"), my weight (~130), and whether or not I am a smoker (no). Here are my calculations, I hope you find them helpful!

Monday

• 3 mile walk to school (50 min): 228 cal  

Comparison: Shapefit.com estimates that a 130 lb person walking 4.0 miles per hour, which is a little faster than I was walking, can expect to burn 236 calories per hour.

• 1 hour basic yoga class at South Boston Yoga which focused that day on hip opening: 141 cal

Tuesday

• 3 mile walk to school: 223 cal

Comparison: Monday the same walk burned 5 more calories - maybe my backpack was heavier that day?

• Sitting in an hour and a half long lecture having walked to school: 92 cal

• 30 minutes on the treadmill, totaling 2.5 miles: 271 cal 

Comparison: The treadmill, knowing only my weight and age, told me I burned 294.4 cal.

Tuesday was the day I burned the most calories - by walking to school, running on the treadmill for 30 minutes during lunch, and walking to dinner and then the train later that night, I burned 2828 calories, took 22,513 steps, and had a total activity time of 276 minutes. Could it be because I had slept for 8 hours and 4 minutes the night before, with 94% sleep efficiency (time laying down versus time actually asleep) making it the best night of sleep I got all week? Perhaps!

Wednesday 

Day off! After awhile you don't really notice the armband during your daily routine and sleeping, but Wednesday I had ghost armband syndrome and kept thinking I was still wearing it.

Thursday

• Sitting in an hour and a half long lecture having driven to school: 85 cal

Comparison: Sitting in the same lecture on Tuesday burned 7 more calories having arrived from walking rather than arrived from driving.

• 1.5 hour boxing class at Boston Boxing and Fitness (mix of jumping rope, weights, sparing, step-ups, push-ups, lunges, etc): 434 cal

Comparison: Shapefit.com estimates 354 cal/hr of "boxing, punching bag" but that jumps to 531 if you're "boxing, sparring" and 708 cal/hr if you're "boxing, in ring, general." 

Friday

• Spin class at Sweat and Soul, 45 minutes long on Real Ryder bikes: 226 cal

Comparison: The instructor estimated 800 when I asked him how many calories one could expect to burn; a Body Media rep says via e-mail "When using certain gym equipment you may notice that your overall armband information may be lower than it should be. This is due to the fact that the abnormal and usually smooth motions throw off the accelerometers in the armband. Different equipment can affect the overall accuracy of the armband in many different ways." I think that the number is on the low side, but it was also only a 45 minute class and I wasn't panting, though I did sweat completely through all of my clothes so maybe a more accurate estimation would be around 300 calories.
 

Note: These Real Ryder spin bikes are pretty cool. They're supposed to mimic real riding on the road so they move to the left and right - and you really have to engage your core in order to turn them. See the above video for an example. 

Saturday

• Stair running at Harvard stadium (the little stairs that you use to enter the stadium, up one set and down the next around the entire stadium and back which took approx 25 minutes): 187 cal

Sunday

• Hour long Zumba class at ZYP Fitness Plus: 391 cal

Comparison: The ZYP website says participants can "dance away their worries & 500-700 calories." Before I went to the class I never would've guessed that I would get such a good workout but you literally move (or shake) your whole body the entire time - so don't underestimate this as a really good full body workout.

Special thanks to Rachel, Lea, Barrett, Dan, Chris, and Meredith who suggested workouts and then kept me company (or brought me along)!

I'm planning on borrowing the armband again in the spring so that I can track calories burned for fun outdoorsy activities like cycling, hiking, and running. Is there an activity that you've always wondered about? (Besides swimming since you cannot submerge the armband.) Let me know in the comments section and I'll write about it next time! Interested in learning more about Body Media, how it measures calories burned, or how it compares with other armbands out there? Check out their comprehensive website.