Finger Pulse Oximeter

I seriously need to monitor my oxygen level and pulse rate when exercising, I almost pass out the other day while using the treadmill, my body cannot handle too much running that almost causes me to pass out. I have asthma in my younger age and I think it’s the reason why it affects my breathing while running in the treadmill. I am thinking to get those finger pulse oximeter to monitor my body accurately, I know how to get body vital signs but I still prefer to use the other one because it’s easier for me to use and very accurate. I’ve seen some in the store nearby and I cannot wait to get one and start my daily exercise again.