Heart beat during slow walking is same as when I doing HIIT

[Sophy]

I'm 25 with resting bpm around 70. I'm 110 lbs with 5'5. My just got my blood work this week and my LDL cholesterol is borderline high. When I'm doing HIIT, my heart beat is mostly 90bpm-110bpm. But when I'm just walking, it's always 90+ and sometimes goes to 100+. And in recent 1-2 weeks I would sometimes feel slightly short of breath, but I don't feel short of breath when I'm concentrating in work, sleeping or doing exercise. Not sure if it's because I'm too anxious about it. Do I need to go to see a doctor?

[Dopovo]

Hello @Sophy,

whta tracker do you use?

[Sophy]

Mine is a Sense 2

[Dopovo]

I think you mean Sense as Sense 2 is not yet available. If you confirm it's a Sense well, Sense is notorious to have a terrible heart rate sensor that fails miserably when working out. 

I think therefore it's plausible your heart rate is ok and you should replace your Fitbit device rather than going to see a doctor.

[Sophy]

oh thank you you're right. I have a fingertip oximeter monitor. I just tested， and the oximeter shows 80+ BPM when fitibit shows 100+.