caffeine and calorie burn

I don't normally drink my caffeine right before a workout... just so you know.

But today I drank a full can of Low Carb Monster (I'm pretty caffeine tolerant, so this is not unusual for me) and then I went on my morning walks. I wore my HRM. For my 30 minute walk with one dog, I burned more calories with less effort than I usually do... because the caffeine jolt kept my heart rate up. (I don't really consider this a "workout" by strictest sense of the word, but it is steady activity that I monitor)

What I want to know is this: did I actually burn more calories, or does my HRM just perceive my higher heart rate as higher intensity? Is the correlation between heart rate and calorie burn black and white? Does a higher heart rate always equal a higher calorie burn, even if it is attributed to caffeine?

If someone knows of a good article that could answer my question, or if you have some knowledge in this area, I'd appreciate some input. Again, this isn't a normal habit, but given my "taste" for caffeine, it's bound to happen once in a while.

Calorie burn is relative to oxygen consumption more than heart rate. An elevated heart rate can be indicative of higher intensity or just a stimulant, like in this case. Caffeine does cause extra calorie burn, but not to the extent of actually elevating your HR to that level with exercise.

I'm a little unclear of what you're saying... I understand the oxygen consumption part. Does this mean that I likely didn't burn as much as my HRM suggests?

Calorie burn is relative to oxygen consumption more than heart rate. An elevated heart rate can be indicative of higher intensity or just a stimulant, like in this case. Caffeine does cause extra calorie burn, but not to the extent of actually elevating your HR to that level with exercise.

I'm a little unclear of what you're saying... I understand the oxygen consumption part. Does this mean that I likely didn't burn as much as my HRM suggests?

Correct. Each extra heartbeat would burn a small fraction of a calorie, so you're burning a tiny bit more than you would at a normal HR. But the HRM is assuming a direct correlation between your HR and VO2 levels and that's not always the case. I'd record it as what it normally burns without the caffeine.

Thank you for clarifying... I was kind of suspecting that was the case.

Now I'm feeling the crash... :ohwell:

my hubby just read an article today that said that 1cup of coffee for an average 175lb man will increase exercise and increase calorie burn. So ,you don't have to drink a lot of caffeine to get an increase, and then you wont have the crash afterwards either. I always drink a bit of coffee throughout the day, but my coffee is weak in comparison to many peoples, but a cup before and then lots of water and a cup after and then lots of water, really works for me. I am also a newly non-smoker ( 97 days :happy: ) so to keep the stimulant that my body likes I find that a regular supply of caffeine throughout the day keeps me going. As you can see,:drinker: I am a true coffee girl. "I did stop the starbucks frapp's , too many calories. "they are for special occasions only. I have only had 2 since January.:sad:

Well, I do enjoy a cup or sometimes two in the morning... but when I go for the Monster, it's because I didn't get enough sleep and I can't even function without a fast jolt. Some days, I have extra time to allow the coffee to brew and the slow sipping... and it's nice. But others, I just gotta have it in my bloodstream right now!

I've actually cut back considerably on my caffeine problem. When I was in the desert, I was eating these mints called "FOOSH" all day every day. Each mint contains 100 mg of caffeine. I sometimes needed like 5 in a row to feel anything! Talk about issues. I built up quite a tolerance, which can be expensive to feed... not to mention problematic for heart health later down the road.

*edit* I used to joke with my comrades that I was going to start mass producing vending machines that sell syringes filled with liquid caffeine. You would have to put in like $10 for a dose, but you'd get $5 back for putting the empty syringe back into the machine...

Congrats on quitting smoking! That's pretty awesome!