BMR/RMR - Activity Factors Question

Question:

When I look up my BMR/RMR, there's always an "Activity Factor" - does this factor account for any exercise you might do during the day, or does your weekly activity boost your metabolism as a rule, and then if you exercise, you burn additional calories?

For example, My BMR is ~1308, my activity level is moderate.  Many sites tell you to multiply your BMR by 1.55 for moderate activity... so, that would equal ~2,027 cals per day.  If I get a 300 calorie workout in, will I burn 2,327 cals on that day, or does the 2,027 calorie estimate suppose I have done that workout?

Hope this makes sense - thanks for the help!

its suppose to include ur 300 calorie workout. Moderate exercise is subjective. 300 calories for me would be light. If thats the only exercise u do then ur total cals should be 1608. u overestimated by over 700

So unless you are moderately active without the exercise (say your job keeps you moving a lot), you don't get to multiply by the 1.55 and also add the exercise - you have to pick one.

If you decide to add in the exercise, you'd first multiply BMR by 1.2 (sedentary multiplier), then add in the 300 cals. And if workouts tend to be 300, I wouldn't call that moderately active - more like light (1300*1.2 + 300 = ~1800;  1300*1.375 = ~1800)

However (oh, this just gets confusing) - if you are lightly active during the day, plus you exercise, you could use the light activity multiplier (1.375) and add the 300 cals exercise to that, and probably get about the same as if you just used the moderate multiplier (1300*1.375 + 300 = ~2100).

Oh, cc burn meter does this for you (by setting your activity level in the account settings and logging, or not, your exercise) - but cc goes a step further, and subtracts the calories you would have burned being sedentary but instead burned at a higher rate.

So if you exercise for an hour, and you would have burned 60 cals in that hour being sedentary, instead you burned 300 cals (which you log), the burn meter will only go up 240, because it has to take away the 60 cals it thought you'd burn then.

Sorry, that was long. Let me know if it was unclear.

Amethyst -

Thanks so much, this helps immensely.

I wore my HRM for 24 consecutive hours yesterday, and it came up with 2,399 for the whole day.  What do you think is more accurate?  The ~1,800 from CC or the ~2,400 from my HRM?  If it was a 100 - 200 calorie difference, I wouldn't wonder so much... but 600 calories is A LOT!

Let me know your thoughts - thanks again!

~t

Unless you have the bodybugg, hrm are not designed to be worn outside of exercise, and won't give you an accurate count. I'd go with the cc count to start, but play around with the number til you find what works - cc is still just an estimate, and can't take into account your metabolism, muscle mass, etc.

thanks again - I'll go with the CC site recommedations and play around like you suggest.

two more questions if you don't mind:

1. What is the difference between a bodybugg and a traditional HRM?  Why is a HRM not good for measuring daily calorie burn and a bodybugg is? I looked up bodybugg's website, but they don't address this - wondering if you have more info you can share.

2. How long should I try an intake number before I determine whether it's working or not?  I don't want to give up too soon!

thanks so much for all the help and advice - I REALLY appreciate it!

~t

To question 1 - it has to do with the formulas they use. I have no idea what bodybugg does to allow it to monitor calorie burn at lower heart rates (and I'm not surprised they don't explain it on their website - if they give too much away, there will be a much cheaper one on the market in minutes). But I think I can safely say that your typically polar hrm that measures burn (remember, not all of them do) uses a formula that only works within a range of heart rates. And no, I dont' know what that range would be.

As for when to play around with the numbers - you kind of have to feel it out. Sometimes you can see that things are going well, so you keep going with that calorie target (or calorie range, for my preference); and you also have to go with how you feel - if you are trying to stick to a target, but it's too low and you are miserable - screw patience!

You might want to check out www.phord.com/cc to get a second opinion on cc's stats (it tends to give a little better estimate for a calorie target). I found it gave a better estimate for me.

You are great - thanks so much for all the help and advice.  I think I was confusing myself with too much info!

I really appreciate it - thanks again!