Blaze showing heart rate and calories too high

[jwales]

I noticed today that my blaze (which has seemed to be pretty accurate overtime, though a little high on calorie estimates) was massively high when I did a full day of yard work in 90+ degree weather. My heart rate stayed above 120bpm most of the day due to being very hot and doing manual labor. Even when I was sitting around or doing light work, due to the heat my heart rate stayed up (it is normal for heat to raise your heart rate). I normally burn 2700 calories on a 10000 step day. Today my Fitbit says 18000 steps but 5500 calories (so far). I’ll break 6000. That’s unheard of for me. Even with the level of exercise I did today it seems way high. I’m pretty sure the Fitbit is assuming my heart rate was 120 due to exertion and not heat. I know my heart burned calories doing all that beating but it still seems wrong.  Have others experienced that? Has Fitbit considered using skin temperature to compensate for heat induced heart rate (and maybe warn people about heat stroke)?

Moderator edit: updated subject for clarity

[MarreFitbit]

Welcome to the Community Forums @jwales! I'm sorry for the late response. 

Heart rate may be affected by any number of factors at a given moment. Movement, temperature, humidity, stress level, physical body position, caffeine intake, and medication use are just a few things that can affect your heart rate. Different medical conditions and medications can impact your heart rate. Consult your doctor before starting an exercise routine. I'd recommend taking a look at the help article: How do I track my heart rate with my Fitbit device? 

In regards to the calories, my first recommendation would be to have you check your personal settings. Just make sure that your weight, height, age and all other personal information is entered correctly as this is how your tracker will calculate your calories burned.

If all seems to be okay in your personal settings, try to give your tracker a quick restart and also try to set it up as a new device and see if this helps.

[jwales]

All my info and settings are correct. I realize the estimates aren’t perfect. I can restart my Fitbit but other than this scenario in the heat the calorie counts are very good. 

My point is that it’s a known thing that heart rate goes up with heat by about 10bpm / degree of body temp so when hot the Fitbit thinks I’m in cardio or fat burn but really I’m just walking or sitting and it’s way way off if it’s using heart rate to estimate exercise. 

https://www.google.com/amp/s/health.clevelandclinic.org/how-hot-weather-can-affect-your-heart-when-y...