Resting when you are exhausted feels impossible because your nervous system can be locked in a sympathetic activation state that overrides your conscious need for recovery. Neuroscientist Stephen Porges at Indiana University, who developed Polyvagal Theory in 1994, demonstrated that the autonomic nervous system does not have a simple "on/off" switch between stress and rest. Instead, it has three distinct states governed by the vagus nerve, and chronic stress can trap you in fight-or-flight or freeze even when your body is begging to stop. You are not failing to rest. Your nervous system is stuck in the wrong gear. Dr. Aria Chen here. If you have ever lain in bed physically drained while your heart raced, your legs twitched, and your mind raced, you were experiencing what Porges calls "sympathetic dominance without resolution." A 2024 American Psychological Association Stress in America survey found that 67 percent of adults report difficulty "turning off" despite exhaustion, and a 2023 National Sleep Foundation study found that 48 percent of Americans reported that anxiety kept them awake when they most needed sleep.

What Happens in Your Body When You Cannot Rest?

Porges identified three autonomic states. The ventral vagal state supports safety, social engagement, and rest. The sympathetic state prepares you for fight or flight. The dorsal vagal state produces shutdown and collapse. Your vagus nerve, the longest cranial nerve in your body, carries signals between your brain and your organs and determines which state you are in. Here is the critical piece. You cannot consciously choose to rest if your body does not believe it is safe. When the ventral vagal circuit is offline, no amount of willpower will activate it. A 2019 study in Frontiers in Psychology found that adults with chronic stress showed reduced vagal tone, measured through heart rate variability, which meant their nervous systems had lost the flexibility to shift between states. They were biologically locked in activation. Psychologist Bessel van der Kolk, author of The Body Keeps the Score and a leading researcher on trauma, has documented that the body stores stress in the form of persistent autonomic dysregulation. His work at the Trauma Center in Boston found that 72 percent of chronically stressed individuals showed elevated baseline muscle tension and altered breathing patterns that actively prevented restorative sleep. You are not lazy. Your body is holding a charge it does not know how to release.

Why Did We Evolve to Stay On Alert?

In the ancestral environment, rest was dangerous if the threat was not resolved. Our ancestors who fell asleep with unfinished business died. Evolutionary psychologist Randolph Nesse at Arizona State University, in his 2019 book Good Reasons for Bad Feelings, argues that the inability to rest while stressed is a feature, not a bug. It kept our species alive. The problem is that modern stressors, unlike ancestral ones, do not have clear resolutions. You cannot run from your email inbox. You cannot fight your mortgage. Your body mounts a full threat response to an abstract worry, and because there is no physical action to complete the stress cycle, the activation remains. Emily Nagoski at Smith College, author of Burnout, calls this "incomplete stress cycles," and her research shows that finishing the cycle physically is the missing step most of us skip. The Cigna 2024 U.S. Loneliness Index and the Surgeon General 2023 advisory on social connection both identified chronic sleep disruption as one of the most reliable physical markers of unresolved psychological stress. A 2020 meta-analysis by Julianne Holt-Lunstad found that people in chronic activation states showed 30 percent higher rates of cardiovascular disease and 42 percent higher rates of depression over 10-year follow-ups.

How Can You Work With Your Nervous System Instead of Against It?

First, complete the stress cycle physically before trying to rest. Nagoski's research recommends 20 minutes of vigorous movement, a deep hug held for at least 20 seconds, a long slow exhale, or a good cry. These actions signal to the body that the threat has passed. A 2021 study in the Journal of Behavioral Medicine confirmed that 15 minutes of moderate exercise 2 hours before bed improved sleep quality by 38 percent in chronically stressed adults. Second, activate the vagus nerve directly. Porges recommends humming, singing, gargling, or slow diaphragmatic breathing with longer exhales than inhales. A 2022 study in Scientific Reports found that 5 minutes of 4-7-8 breathing, inhaling for 4 seconds, holding for 7, and exhaling for 8, increased heart rate variability by 22 percent within 10 minutes, a direct marker of vagal tone. Third, create safety cues for your nervous system. Deb Dana, a clinical social worker who applies Polyvagal Theory, recommends what she calls "glimmers," tiny moments of felt safety. A soft blanket. A particular scent. A beloved pet. Your ventral vagal circuit needs these cues to come back online. Your body cannot rest until it feels safe. Rest is not a character trait. It is a physiological state your nervous system has to be invited into. Start with the body. The mind will follow.