HRMs and all these other machines?!?!

HRM is going to be the least expensive. However, while more accurate than a fitness machine or MFP, is less accurate than...

BodyMediaFit or BodyBugg. Both of these require a monthly subscription, which while more monetarily speaking than...

FitBit, a glorified pedometer...

The BMF and BB both, not only track along four different metrics, but they modify your estimated TDEE to keep in line with your ACTUAL weight loss/gain making them the MOST accurate over longer periods of time.

I have both a FITBIT and a HRM. The FITBIT is an interesting little toy. It's fun to see how much I walk in a given day. I'm a terrible sleeper, so the sleep monitoring is a nice function.

The FITBIT senses motion, usually the legs. When I work in the garden or do weights at the gym, it doesn't feel what I do with my arms. Most of my time at the gym is labeled as 'sedentary'. Doesn't seem that way to me.....

The HRM goes off of my heart rate. Some HRM's use an averages chart that doesn't use your actual heart rate. ( *Most* people your age/height/weight would burn X # of calories in that time.) The FITBIT kinda does the same thing.

My HRM is a Garmin FR60. Nothing too fancy, but it does use my actual heart rate. I use it for serious exercise.

Why I said the BMF or BB are not accurate for exercise level stuff, no matter the fact they have sensors.
Started with using one for many months, wondering why it was bad on many estimates. For instance, morning activity after the shower moving arms around is rated as Vigorous Activity and given high calorie count. Because the arm is moving.
That made me research the claims, and while studies say great for daily non-exercise stuff, this study measured the exercise stuff.

Mind the comment in the study, if activity specific algorithms could be applied, it would be more accurate. But those devices don't ask for what your activity type was during a period of time. And if you gather data during a period of time, you cannot enter in your own more accurate HRM estimate of calorie burn.
Very annoying and not worth the monthly fee. Great for 1 or 2 weeks to estimate what daily non-exercise TDEE might be though. But for that much money, just get nicer HRM.

On, Sensewear is who makes those BMF and BB models, and several others with different labels slapped on them.

http://www.ncbi.nlm.nih.gov/pubmed/15126727

PURPOSE:
To assess the accuracy of the SenseWear Pro Armband for estimating energy expenditure during exercise.

METHODS:
: Forty subjects (age = 23.2 +/- 3.8 yr; body mass index = 23.8 +/- 3.1 kg x m) performed four exercises (walking, cycling, stepping, arm ergometry) with each exercise lasting 20-30 min and workload increasing at 10-min intervals. Subjects wore the SenseWear Pro Armband on the right arm, and energy expenditure was estimated using proprietary equations developed by the manufacturer. Estimated energy expenditure from the SenseWear Pro Armband was compared with energy expenditure determined from indirect open-circuit calorimetry, which served as the criterion measure.

RESULTS:
: When a generalized proprietary algorithm was applied to the data, the SenseWear Pro Armband significantly underestimated total energy expenditure by 14.9 +/- 17.5 kcal (6.9 +/- 8.5%) during walking exercise, 32.4 +/- 18.8 kcal (28.9 +/- 13.5%) during cycle ergometry, 28.2 +/- 20.3 kcal (17.7 +/- 11.8%) during stepping exercise, and overestimated total energy expenditure by 21.7 +/- 8.7 kcal (29.3 +/- 13.8%) during arm ergometer exercise (P < or = 0.001).
At the request of the investigators, exercise-specific algorithms were developed by the manufacturer and applied to the data that resulted in nonsignificant differences in total energy expenditure between indirect calorimetry and the SenseWear Pro Armband of 4.6 +/- 18.1 kcal (2.8 +/- 9.4%), 0.3 +/- 11.3 kcal (0.9 +/- 10.7%), 2.5 +/- 18.3 kcal (0.9 +/- 11.9%), and 3.2 +/- 8.1 kcal (3.8 +/- 9.9%) for the walk, cycle ergometer, step, and arm ergometer exercises, respectively.

CONCLUSIONS:
It appears that it is necessary to apply exercise-specific algorithms to the SenseWear Pro Armband to enhance the accuracy of estimating energy expenditure during periods of exercise. When exercise-specific algorithms are used, the SenseWear Pro Armband provides an accurate estimate of energy expenditure when compared to indirect calorimetry during exercise periods examined in this study.

And it rates favorably with the FitBit style of device, at least for running.

http://www.ncbi.nlm.nih.gov/pubmed/15235333

PURPOSE:
To evaluate the validity of five physical activity monitors available for research: the CSA, the TriTrac-R3D, the RT3, the SenseWear Armband, and the BioTrainer-Pro.
METHODS:
A total of 10 healthy men and 11 healthy women performed 10 min of treadmill walking at 54, 80, and 107 mxmin and treadmill running at 134, 161, 188, and 214 mxmin. The CSA, TriTrac-R3D, RT3, and BioTrainer-Pro accelerometers were placed side by side bilaterally at the waist in the axillary position, and the SenseWear Armband monitors were placed bilaterally on the posterior portion of each arm in the mid-humeral position. Simultaneous measurements of body motion and indirect calorimetry were continuously recorded during all exercise. Data were analyzed with repeated measures ANOVA and pairwise Bonferroni-adjusted estimated marginal means.
RESULTS:
: There was no significant difference in the mean energy expenditure (EE) recorded bilaterally by any of the monitors (P < 0.05) at any treadmill speed. The SenseWear Armband, the TriTrac-R3D, and the RT3 had significant increases in mean EE across all walking and running speeds (P < 0.05). Below 161 mxmin, the mean EE recorded by the BioTrainer-Pro and the CSA increased significantly (P < 0.001); however, there was no significant difference (P > 0.10) in mean EE recorded by either monitor for speeds above 161 mxmin. In general, all monitors overestimated EE at most treadmill speeds when compared with indirect calorimetry (P < 0.001), except for the CSA which underestimated EE at the lowest and highest speeds.
CONCLUSION:
The CSA was the best estimate of total EE at walking and jogging speeds, the TriTrac-R3D was the best estimate of total EE at running speeds, and the SenseWear Armband was the best estimate of total EE at most speeds.

Why I said the BMF or BB are not accurate for exercise level stuff, no matter the fact they have sensors.
Started with using one for many months, wondering why it was bad on many estimates. For instance, morning activity after the shower moving arms around is rated as Vigorous Activity and given high calorie count. Because the arm is moving.
That made me research the claims, and while studies say great for daily non-exercise stuff, this study measured the exercise stuff.

Biking & swimming are the only exercises that BMF/BB are bad at calculating. It's not just registering movement, it's also body temperature and galvanic skin response (basically electrical conductivity of sweat). If you were off after your morning shower, it's likely because you take hot showers. The hot, moist skin added to vigorous arm motion would register for a few minutes of intense activity, which would not overly affect the overall daily number.

When first used, both devices are using a base average for your height/weight/sex and will be as inaccurate as any other estimate. However, by tracking your activity and then matching it to your actual loss/gain it is able to calculate an accurate number for the individual.

4 months of use.
Several proof points that showed me the sensors aren't up to everything they claim.

Running inside gym on treadmill with fan, level. 130 HR. Some sweat.
Running outside in 95 F humid summer, hill intervals, 160-170 HR. Pouring sweat.
Same feet turnover and arm swing.
Same per min calorie burn estimate for the time for both. Glad I had a HRM on.

Left unit in bathroom couple busy mornings, it was resting on the elastic band. It thought it was on-body the whole day. It did not stay moist enough all day. Company confirmed on tech support call that can happen. The galvanic sensor is for telling if the unit is on-body, think 9-volt battery on tongue.

Several nights of difference between sleeping in the cool, and sleeping in the warm, with me feeling the difference big time of course. That is a known effect on metabolism, warm should have been higher.
Same per min calorie burn for different nights.

Besides starting to take it off so I could manually enter my own more correct HRM info into the stats, the final straw that made me say forget it, well this and the studies I found.
8 hr day chainsawing a tree. Fall weather, not too hot at all, no sweat, no breathing hard, no high HR.
Plenty of up and down, arm movement, and vibrating of course, even though band was on non-chainsaw arm.
Got my highest calorie count of any workout the BMF had ever recorded x 3.

You might want to reread the study I post, it was not just swimming (not waterproof anyway so that isn't possible).

And the adjustment for base temperature at night doesn't take long at all from the standard BMR estimate they start off with for basing calorie burns on. About 3 days was it.

But I saw enough evidence outside the studies that showed the sensors aren't all they are cracked up to be, except the 3-axis motion sensor, which the FitBit has too.