Bodymedia and adjusting METS

Theocakes

Hello,
I previously swore that I would not get a bodymedia as I thought my hrm was good enough. Well, I broke down and bought one after talking more to my SIL about hers. I am surprised at how accurate it is, especially in the sleep area. I'm also surprised (not really) at how few calories I am burning on lazy days. It's really helped a lot and I've already lost 3 pounds in one week...mainly because I see I haven't burned enough calories to eat a snickers...lol

Anyway, one area I would like some clarification on is the MET level. I have been reading about METS and how MET varies (like everything else in life) from person to person. I also know that you can change your MET on the body media based on personal goals and fitness levels. I've been doing insanity for a few weeks now and just started the program again and I don't agree with the amount of vigorous activity that the bodymedia is saying that I have done. I feel like I am pushing it harder than I ever have but I see that the bodymedia says I've only done 4 minutes of vigorous activity.

I lowered the threshhold for vigorous activity to 5 to see how it changes things and it shows that I did 23 minutes of vigorous activity.

I had a baby about 5 months ago and I am terribly out of shape from the pregnancy and I am carrying quite a high body fat percent for my size. So does this sound about right that my MET is probably lower than the average person right now?

FitLink

My understanding is that a MET is a set amount, and what you can set on the BodyMedia FIT is how many METs are needed for an activity to be considered "moderate" or "vigorous." MET is a scientific unit of measure, like an inch or a pound, it doesn't vary from person to person--it's a unit of energy. How many METs a given person burns doing their daily activities is what the BodyMedia FIT is measuring, based on four things--motion and position, galvanic skin response (sweating increases this), skin temperature, and the rate at which your body is shedding heat.

The more out-of-shape one is, the fewer METs one burns at any given activity, so if you're not fit due to recent pregnancy it would take more effort to produce 5 or 6 METs than if you were fit. As you get fitter you should see more METs for your activities and greater calorie burn, so more weight loss from less activity. (Ironic, I know!)

The great value of a device like the BodyMedia FIT is that most of us believe that we're burning a lot more calories than we really are. Your HRM doesn't measure things like body temperature or GSR, so it can, and probably does, overestimate your calorie burn.

This will change as you get more fit. Meanwhile, remember, the FIT is providing you with valuable information to help you get more fit., even if it's not what you wanted to hear.

BTW, there are good reasons why one might want to adjust what moderate and vigorous activity are. I am disabled and walk with crutches. Odds are I can never achieve 6 METs no matter how fit I get. For me, a better goal is 2~4 METs moderate, and 4 METs vigorous. Whatever you choose needn't be permanent. If it's more encouraging to you to lower the criteria for METs, you can always raise it when you are more fit.

ChinniP

Very good explanation.

jaz050465

I'm trying to persuade myself to invest. Would you recommend it. I don't have much to lose but then need to think about maintenance. My plan is to get a used one, use it for three months to gather information and then sell it on. What do you think.

Azdak

My understanding is that a MET is a set amount, and what you can set on the BodyMedia FIT is how many METs are needed for an activity to be considered "moderate" or "vigorous." MET is a scientific unit of measure, like an inch or a pound, it doesn't vary from person to person--it's a unit of energy. How many METs a given person burns doing their daily activities is what the BodyMedia FIT is measuring, based on four things--motion and position, galvanic skin response (sweating increases this), skin temperature, and the rate at which your body is shedding heat.

The more out-of-shape one is, the fewer METs one burns at any given activity, so if you're not fit due to recent pregnancy it would take more effort to produce 5 or 6 METs than if you were fit. As you get fitter you should see more METs for your activities and greater calorie burn, so more weight loss from less activity. (Ironic, I know!)

The great value of a device like the BodyMedia FIT is that most of us believe that we're burning a lot more calories than we really are. Your HRM doesn't measure things like body temperature or GSR, so it can, and probably does, overestimate your calorie burn.

This will change as you get more fit. Meanwhile, remember, the FIT is providing you with valuable information to help you get more fit., even if it's not what you wanted to hear.

BTW, there are good reasons why one might want to adjust what moderate and vigorous activity are. I am disabled and walk with crutches. Odds are I can never achieve 6 METs no matter how fit I get. For me, a better goal is 2~4 METs moderate, and 4 METs vigorous. Whatever you choose needn't be permanent. If it's more encouraging to you to lower the criteria for METs, you can always raise it when you are more fit.

I don't know about the Bodymedia system and the setup, but I wanted to clarify one thing you said about METs.

The more out-of-shape one is, the fewer METs one burns at any given activity

This is only true if you are doing some type of general activity --such as a group class -- where the intensity of effort is controlled by the individual. In that case, yes, the less fit person cannot push themselves as hard, and therefore will be working at a lower MET level (which disproves the whole "muscle confusion" nonsense).

If one is doing an activity at a fixed workload (e.g. treadmill ), then the MET level is determined by the workload, not the person's fitness level. A person walking at 4.0 mph works at the same MET level (~4.2 METs), regardless of their fitness level (or age, gender, and height, for that matter).

You mentioned that in your first paragraph, but people are often confused because they see their heart rates decrease for a certain workload level and so they assume they aren't working at the same MET level, so I just wanted to further explain that, yes, you are working at the same MET level--it's just that now your maximum fitness level has improved. This means that the workload now represents a smaller percentage of you max, and THAT accounts for the HR drop.

platinummontu

Very informative and clear. Appreciate the input from you both.

rockerbabyy

ive been toying with the idea of adjusting my METs on BMF settings - but not sure if i should or not. im not really at a point right now where i can do much vigorous anything (8 months pregnant), but it seems like days when i work (clerk @ a gas station) and am on my feet all day and putting orders away/stocking shelves would be higher METs than just walking up and down the stairs at home. maybe i just dont understand it well enough.
my weight has kind of been going up faster than the BMF says it should (im actually set to maintain) but i figure they werent really tested on pregnant women and im still within the healthy weight gain range my dr set for me.

musicalssm

Thank you for the explanations of how METS work. I really appreciate it. I was a little confused when I went to work with my trainer and my heart rate was frequently (and at points consistently) in the 180s with a peak of 191, but the monitor showed no vigorous activity. I guess I will just have to keep working for a few months to get up to that. I think this is really going to help me put my intake vs. expenditure in proper perspective.

jaz050465

Am I wrong in thinking that adjusting mets doesn't effect your calorie burn figure, just the number of minutes of activity you do.

chrisbdavid

Hello All,

I just wanted to clarify a little on MET(s). It stands for Metabolic Equivalent of Task. It is an physiological measure of expressing the energy cost of physical activities.

1 MET = 1(kcal/(kg * h).

So that is calories burned divided by your height times your weight. This is basically a ratio to determine how hard you are working for your body size

It DOES involve the weight of an individual and it DOES involve the number of calories burned. The trick is that the 'EFFORT' of burning calories for your height and weight are standardized.

1 MET is standardized to the average person at rest (an rough estimation of your Resting Metabolic Rate (RMR)). That means that the number of calories your burn at rest is typically consistent with your weight times your height. Now obviously there are variances, but with a body monitor you can determine the number of MET(s) your body averages at rest.

By definition 2 METS means that your body is working roughly twice as hard as it is at rest (usually about a 2.5 mph pace). Moderate intensity activities are defined as between 3 and 6 MET(s) and vigorous activities are great than 6 MET(s)

Jumping rope is ~ 10 MET(s). This is a great measurement to determine how hard you are working. Obviously a lighter person jumping rope is burning less calories, but it is still 10 MET(s) because even though they burn fewer calories, they weigh less, so the ratio is similar.

The problem with using MET(s) is that it is a 'standardized' unit of measure developed by researchers based on an 'average' population that participated in the study. If you ever meet an 'average' person let me know ;-) We are all different, but as a means to quantify how hard you are working, MET(s) are the way to go.

Also, it is difficult to standardize a 300 lb body builder against a 300 lb couch potato. Someone in shape might be able to maintain 10 MET(s) for an extended period of time, but someone who does little activity could find it nearly impossible to maintain. But, the rich stay rich and the healthy stay healthy. All that matters is that you push yourself and one day you can achieve whatever fitness goals you desire.

DianeLynnKohnen

Okay, you seem very knowledgable and I am searching on this topic because I have a body media and had done workouts and they were intense yet it showed no vigorous activity. When I looked at my mets, they were set that anything above 9.9 was vigorous. So, I readjusted them to the 6 and higher and after I did, I am pretty sure my 'calorie burn' went up. Would that make sense and if so, could you explain it?