Why my Heart Rate is dropping after switching from a Charge 2?

[DeanoDeano1]

Hi everyone been using a fitbit Charge 2 since July and managed to get a decent heart score from 51 average to 62 excellent over 7 months of cardio and fitness... since upgrading to the ionic my heart score is dropping constantly from 62 now down to 56 which is one point away from average. I train every night and getting faster and a lot more stamina, doing from 5 to 7 mile runs a night... confused at how my heart score is dropping, noticed the readings saying I am hitting 203bpm!? Wearing the ionic correctly during runs as per fitbit advice... I did notice that the watch sometimes said when resting I was at about 69 but when taking a manual reading I was much lower about 10 bpm lower, after about 10 seconds it seemed to Catch up... is it a bug or is it faulty.. ionic is brand new btw ... thanks 

ps just to mention my Charge 2 never went over 170 and spent most my time in fat burn were as the ionic am constantly in cardio and peak

Moderator edit: updated subject for clarity

[MarreFitbit]

Thanks for stopping by @DeanoDeano1, hope you're doing great! As you may know, your heart rate may be affected by any a number of factors at any 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 as well.

When your heart beats, your capillaries expand and contract based on blood volume changes. PurePulse LED lights on your device reflect onto the skin to detect blood volume changes and finely tuned algorithms are applied to measure heart rate automatically and continuously. The heart-rate icon you see on the display tells you if you're in 1 of 3 heart-rate zones.

Resting heart rate refers to the heart rate measured when you’re awake, calm, comfortable, and have not recently exerted yourself. We use your heart rate data from when you’re awake and asleep to estimate your resting heart rate. For best accuracy, wear your device to sleep. 

Your resting heart rate is usually higher than your heart rate while you are asleep, so don’t be surprised if your resting heart rate is higher than the lowest number that you see in your heart rate graphs.

Your tracker can have difficulty finding a signal, typically due to the tracker's fit. For example, wearing your band tightly may constrict blood flow in your wrist and affect the signal. We recommend experimenting with how high you place the tracker on your wrist. When you're not exercising, wearing the tracker just above the wrist bone--as you would a watch--typically works fine. However, moving the tracker up a couple inches can be helpful during high-intensity exercises or exercises that cause you to bend your wrist frequently. If you haven't already done so, please review our recommendations for wear and other tips shared by @SantiFitbit. 

If you're wearing the tracker correctly and the heart rate setting isn't turned off, try changing the setting from On to OFF and then sync your tracker, afterwards go back to the original setting On and re-sync your tracker. The change won't take affect until you sync. If heart rate doesn't seem to start tracking correctly, try restarting your Ionic.

Note that on Fitbit Ionic, the heart-rate value appears gray if your watch is searching for a stronger reading.
 

Occasionally your device may have difficulty getting a strong signal. If you don't see your heart rate on your device, first make sure you are wearing it correctly. After a short wait, you should see your correct heart rate again. On Ionic, make sure the Heart Rate setting is On. For additional troubleshooting, see Why don't I see my heart rate on my Fitbit device?

Give this a go and let me know how it goes!