The following is from the always wonderful Harvard Business Review and can be applied to interviewing. When you have a phone screen, you might be able to walk around. During an in-person interview, you will have to use the place your feet firmly on the floor portion of the suggestion.
March 15, 2018
Stay Calm During a Tough Conversation by Grounding Yourself
Having a tense conversation brings up a lot of negative emotions, leaving you feeling like an active volcano. To prevent an outburst and stay in control of your emotions, physically ground yourself in your environment. One of the best ways to do this is to stand up and walk around, which activates the thinking part of your brain. If you and your counterpart are seated at a table, and suddenly standing up seems awkward, you might say, “I feel like I need to stretch. Mind if I walk around a bit?” If that doesn’t feel comfortable, you can do small physical things like crossing two fingers or placing your feet firmly on the floor and noticing what it feels like. Mindfulness experts call these actions “anchoring.” Whatever you can do to focus on your physical presence and your senses will help you stay grounded and get through that tough conversation.