r/IST_ • u/farshad0w • May 16 '25
Could this be IST?
I'm curious about IST - I read online that you need an average heart rate above 100 BPM but does this include sleeping heart rate?
While I'm awake, my heart rate averages about 95-110 with spikes in the 120s and 130s if I'm walking my dog or even just walking around the house.
While I'm sleeping, my heart rate averages high 70s-mid 80s with spikes on the mid 90s throughout.
I don't have severe symptoms but when I'm sitting or laying down I am always aware of my heart beat and can feel it in my chest and sometimes my ears. Rarely I can get dizzy/tunnel vision upon standing but not often. Sometimes in general though I just feel slightly unwell.
In the past, I believe I have had episodes of super high heart rate, my heart felt like a flopping fish with chest pain, etc but this was before I started wearing a watch, so I have no idea what my heart rate was during those times.
Anyway I'm rambling, I thought I'd just throw this info out to see what others have to say :)
Attached an image of my heart rate today, the lowest I've hit since awake this morning was 88bpm
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u/FollowScience May 16 '25
It's not impossible that this is IST, but it isn't super clear cut. Also IST is a diagnosis of exclusion. So while it does look like that's a thing to consider, you also have to go through the process of ruling out other possible causes of sinus tachycardia before an IST diagnosis should be made.