Heart Rate when Doing Mind Meditation

I think my heart rate does decline when doing mind meditation. At least sometimes, my Garmin tells me it did. I find it hard to get my heart rate to go down or get into a calm state when doing Heart Meditation. I think part of the reason is that my body finds the sound of the drumming to be stimulating, nor matter how hard I try to just follow the drum as it slows with my heart. Is there a way to see the chart of heart rate when doing Mind Meditation?