My heart rate generally sits around the 80s to 90s but, on occasions as is happening now it it goes up to 109 . i am not exercising but sitting watch?

Elevated HR: 109 is considered tachycardia but is not extremely high ( 90 is also a bit high) , there is always variation. Do you drink caffeinated beverages or take pills with caffeine? Heat stress/anxiety can also raise HR Would followup with cardiologist to have your heart assessed EKG, echocardiogram stress test since you are 65 and insure that there are no other issues , like abnormal rhythm