Heart Rate Goes Up As You Slow Down

Why is it that when I run and the slow down my heart rate rises before falling. For example if I am on a treadmill and my heart rate is 165 and steady. Then I slow down. My heart rate goes up at least 10 points before rapidly going down. In this case it will go to 167, 171, 175, 178, 162, 155, 140…

Why? Why doesn’t it just decline to start with. I have tried it at other speeds. Like it I don’t run so fast and am steady at 120 it still rises about 10 points the declines quickly.

It is rises really high, if I just quit without tapering off. I am assuming that is why they tell you, and all the treadmills, elipticals etc have the 2-5 minute cool down.

WAG, but I suspect it’s because you stop breathing as heavily. People who are used to running tend to breath in time to their stride. When you slow down your breathing also slows, but your muscles are still repaying the debt from the faster pace. As a result blood CO2levels rise and the heart rate rises. The same happens when you stop. Most people stop and immediately cease breathing as fast or as deep.

Try slowing down but deliberately breath at the same rate. See what happens.

There’s a nice article here - Blood pressure and exercise - going into this. During exercise, your blood pressure is up and there’s a large blood flow to the muscles, whose movement helps pump blood back to your heart. When you slow down, this muscle pump action is reduced and your blood pressure drops, so the heart speeds up to compensate.