Calories not being tracked accurately

[GSHoff]

I have used a Polar watch with chest strap for 4 years..450 calories burned on avg..in boot camp classes for 1 hr..With the Blaze I only burn 300 calories for the same class..Someone explain..Which is right ?? 

Moderator edit: Clarified subject

[FerdinandFitbit]

Hey there @GSHoff. Great to see you in the Fitbit Community Forums! 🙂

Heart rate is closely related when it comes to calories tracking and heart rate accuracy accuracy is affected by personal physiology, location of wear, and type of movement. Please take a look at the following tips that should help making your heart rate readings more accurate.

When you’re not exercising, wear your device a finger’s width below your wrist bone. Fitbit’s PurePulse heart-rate tracking system is designed to be most accurate when the device is worn on the top of your wrist.

For improved heart-rate accuracy keep these tips in mind:

1. Experiment with wearing the device higher on your wrist during exercise for an improved fit and more accurate heart-rate reading. Many exercises such as bike riding or weight lifting cause you to bend your wrist frequently, which could interfere with the heart-rate signal if the watch is lower on your wrist. 
   
2. Make sure the device is in contact with your skin.
3. Do not wear your device too tight; a tight band restricts blood flow, potentially affecting the heart-rate signal. That being said, the device should also be slightly tighter (snug but not constricting) during exercise than during all-day wear.
4. With high-intensity interval training, P90X, boxing, or other activities where your wrist is moving vigorously and non-rhythmically, the movement may prevent the sensor from finding an accurate heart rate. Similarly, with exercises such as weight lifting or rowing, your wrist muscles may flex in such a way that the band tightens and loosens during exercise. Try relaxing your wrist and staying still briefly (about 10 seconds), after which you should see an accurate heart-rate reading. Note that your device will still provide accurate calorie burn readings during these types of exercise by analyzing your heart rate trends over the course of the workout.

Hope this helps and if you're still having problems with this, let me know!