I'm getting way higher readings on one arm and the 8 used an old cheap monitor and it's was normal. It's this common your machine dosent work well the comments on it all say they are high

Are you saying the readings differ between left and right arms using the same Garmin Index BPM

I normally use my right arm, but tested with multiple readings between right, left and right again. Not a huge difference.

Also compared to my Omron BP monitor and the readings were nearly the same.

Or are you saying you used the Garmin Index on one arm and a cheap monitor on the other arm and simultaneously got readings? This can produce skewed results.

• Cross-arm interference: If both cuffs inflate at the same time, they can affect systemic circulation and artificially alter pressure in one or both arms.
• Inflating one cuff slightly compresses the vascular system, which can shift blood flow and affect the other arm’s reading.