One of the simplest and most neglected methods for managing your body's response to anxiety is mindful breathing. The simple act of consciously altering your breath can calm your nervous system and promote your sense of agency over your stress response.
People often associate mindful breathing with meditation. This may bring up associations like, "There's not way I can sit quietly long enough for this to work," "My anxiety is too strong for this to help," or "This is hippie nonsense."
You do not need the patience or spiritual openness of a monk to consciously affect your breathing. And, the fact is that a minute or two of mindful breathing a day can help you train your mind and body. If you are able to tune into your breath and draw your attention to the impact it has on you while you are calm, you will be more able to do so during periods of anxiety.
UCLA's Mindfulness Awareness Research Center (MARC) has some wonderful free guided breathing exercises and meditations. Some are as short as three minutes.
Calm has a great graphic that can help anchor you visually as you practice mindful breathing.
This New York Times article describes additional brief exercises you can explore and a run down of recent research supporting the idea that breathing matters.
Want to keep it really simple? Inhale for a count of 4, hold your breath for a count of 4, and exhale for a count of 8. Repeat this several times and notice how your body feels.
My recommendation: practice a breathing technique once a day for a week. Experiment and see how it feels. You don't have to commit to anything beyond that unless it feels good to do so.
First thing in the morning is a good time to practice. It helps to fold the practice into your routine and establishes that you are making a conscious decision to feel more grounded for the day.
Feel free to reach out for additional breathing techniques.