There are ways of changing how we feel and react and behave, but they are frequently not simple or straightforward.
If someone says, "Please raise your heart rate," despite how hard you think about doing so, you will not succeed.
If you are told, "Please stand up and run around, or think of an exciting thought," your heart rate will increase.
If someone says, "Relax," it doesn't work.
There are things that do work.
You can learn them.