After I picked up the Breezing Metabolism Tracker and fiddling around with it for a while, I was curious to see how BJJ affects my metabolic rate!
Here are links to my previous posts on the Breezing:
While I’m not exactly sure where this table comes from, Tim Bruce has a table showing that:
- Light Brazilian jiu jitsu burns 3.25 calories per hour per pound of body weight
- Intense Brazilian jiu jitsu burns 4.87 cal/hr/lb
Here’s the actual table itself:
The way a typical class at my gym is organized is:
- 20 minutes of warm ups which includes light jogging around the mat with some mobility work including hip escapes, bridges, back rolls, pushups, etc. The intensity is light and I generally have no problem holding a conversation. The closest thing to our warmups would probably be the ‘calisthenics’ category in the table.
- 30 minutes of technique which includes watching the instructor demonstrate the technique and then drilling the technique with a partner. This is also done at a light intensity as my partner and I are trying to learn the technique and ask for feedback. The closest category would probably be ‘stretching light.’
- 40 minutes of sparring. The intensity ranges from light to almost 100% intensity depending on my training partner, so the closest category would be ‘light BJ,’ to allow for a little underestimation.
Since I weight 195 lbs, using the table we can estimate that in one of my 90 minute classes:
- 20 min Warmups (calisthenics) = 2.43 cal/hr/lb x 195 lb x 1/3 hr = 158 cal
- 30 min Technique (light stretching) = 1.81 cal/hr/lb x 195 lb x 1/2 hr = 176 cal
- 40 min Sparring (light BJJ) = 3.25 cal/hr/lb x 195 lb x 2/3 hr = 423 cal
- Total calories in a 90 min class = 757 cal
- Total calories per hour = 505 cal
That’s interesting isn’t it? This is almost 50% fewer calories than estimated by MyFitnessPal and Sparkpeople due to how the actual class is broken down. If a 60 minute class consisted of intense sparring the entire time that would come out to around 950 calories according to the table.
Now let’s see what the Breezing showed
I packed the Breezing with me in my gym bag and used it in the car after I parked outside the gym:
Looks like my metabolic rate was 65 cal/hr which equates to 1560 cal/day which is right in line with my average RMR of 1541 cal/day.
I attended the 90 minute class and when class ended it took about 10 minutes to change and say my goodbyes before I could get back to my car to measure my metabolic rate:
My metabolic rate went up 28% to 90 cal/hr. This seems a lot lower than any of the numbers in the table, I mean even doing yoga should bring me to 1.81 cal/hr/lb x 195 lb = 353 cal. The likely explanation is that the time it took from the moment I finished the last roll to when took my first breath on the Breezing was long enough to let my metabolic rate cool back down.
Looking back on things, if the logistics of the class allowed, and my instructor was cool with it, I should have taken measurements immediately after the warm up, immediately after the technique portion, and immediately after sparring to get the most accurate take.
Just for fun I took a followup measurement 2 hours after the end of class and this is what it showed:
Even after 2 hours, metabolic rate was still elevated to 71 cal/hr which is 9.2% higher than my pre-BJJ rate of 65 cal/hr.
Dang, looking back on this, I did a pretty crappy job at study design, I was so excited to play with my Breezing that I didn’t do a good job of thinking things through.
So what the heck can I actually conclude?
- I burn anywhere from 90 cal/hr to 505 cal/hr in one of my BJJ classes
- My metabolism remains elevated up to 2 hours after class burning an additional 9.2% more calories
Interestingly, in this post, the author mentions a student who wore his heart rate monitor during an entire hour of class which calculated that he burned over 1600 calories. Not sure I buy that.
If you’re interested in trying the Breezing out for yourself:
You can order directly from the Breezing store and use discount code: BJJCaveman
This will give you 10 additional sensor cartridges ($49.98 value) with the purchase of the Breezing. All you need to do is add an additional 10-pack of sensors to your cart, check out, and enter BJJCaveman as the discount code.
It’s important that you select a 10 pack, and not two 5 packs for the discount to work properly.
*Image found here