Biofeedback

Biofeedback is a technique used to learn to control your body's autonomic functions, such as your heart rate, which is your body’s fight or flight response triggered by pain and/or stress. With biofeedback, you're connected to electrical sensors that help you receive information (feedback) about your body. This feedback helps you focus on making subtle changes in your body, such as relaxing certain muscles, to achieve the results you want, to reduce pain and autonomic arousal. In essence, biofeedback gives you the power to use your thoughts to control your body, often to improve a health condition or physical performance.

https://www.mayoclinic.org/tests-procedures/biofeedback/home/ovc-20169724