A lot of my work—including work that predates the Polyvagal Theory—implicitly expands upon Cannon’s definition of homeostasis so that it’s viewed not as a fixed point but as a range that we float within. Psychiatrist Dan Siegel calls this our “window of tolerance,” which I think is a fitting term. 4

Trauma is not defined by the actual event, but by how our nervous system responds to it.

The Green system is crucial to our ability to heal and be happy.

The human nervous system is an intervening variable for how we respond to the world around us, and the same stimuli and experiences can impact all of us very differently.

To me (Stephen), this suggested that COVID is an autonomic disruptor, and a lot of the effects of “long COVID” came from the virus’s ability to do just this.

One of the key tenets of the Polyvagal Theory is that our autonomic state is effectively the lens through which we perceive and experience the world. Our autonomic state doesn’t just change how our organs and bodily functions operate, it also transforms our sensory experience.

This is the heart of co-regulation: We soothe each other out of an alert state of danger, and into a safe space of healing and happiness.

The truth is that our actions impact others. This is true in normal times (our innate interconnectedness is a major theme of this book), but it is especially true during a global pandemic.

Overflowing hospitals also made it difficult for anybody to schedule surgeries or seek treatment for non-COVID emergencies. Many COVID patients died in total isolation from their loved ones, unable to find comfort in a loving hand or accepting smile. Frontline health-care workers endured a prolonged period of stress and trauma that few of us can