The loss of flexibility
The autonomic nervous system is designed to keep you alive. When you encounter a stressor, your sympathetic nervous system kicks in. Your heart rate increases, your breath quickens, and energy is mobilized to help you fight or flee. When the stressor passes, your parasympathetic nervous system engages, slowing your heart rate, restarting digestion, and allowing the body to rest and repair.
This is a healthy, regulated cycle. Dysregulation occurs when the nervous system becomes inflexible. Instead of moving smoothly between states, it gets stuck in one gear, usually as a result of chronic, unmitigated stress or trauma.
Signs of being stuck "on" (Sympathetic Dominance)
When your nervous system is stuck in sympathetic overdrive, you are constantly scanning for threats, even when you are safe. This state requires an immense amount of energy to sustain.
- Chronic anxiety or a persistent feeling of dread
- Racing thoughts and an inability to quiet the mind
- Physical tension, especially in the jaw, neck, and shoulders
- Digestive issues like IBS, bloating, or nausea
- Difficulty falling asleep or staying asleep
- Irritability and a short temper
Signs of being stuck "off" (Dorsal Vagal State)
If the sympathetic state is sustained for too long, the nervous system eventually runs out of energy. It drops into what polyvagal theory calls the dorsal vagal state — a freeze or collapse response. The body essentially shuts down to conserve resources.
- Profound exhaustion that sleep doesn't fix
- Brain fog and difficulty concentrating
- Feeling numb, detached, or dissociated from your body
- A lack of motivation or joy in things you usually care about
- Social withdrawal and a desire to isolate
- Sluggish digestion or a feeling of heaviness in the limbs
"Yoga teaches us to cure what need not be endured and endure what cannot be cured." — B.K.S. Iyengar, Light on Yoga
How to restore flexibility
You cannot talk your nervous system into regulation. It doesn't understand language; it understands sensation, breath, and movement. To restore flexibility, you have to provide the nervous system with physical experiences of safety.
In Iyengar yoga, we use specific practices to address different states of dysregulation. If you are stuck "on," we might use supported forward extensions and long exhales to mechanically down-regulate the system. If you are stuck "off," we might use gentle backbends and standing poses to slowly and safely mobilize energy without overwhelming the system.
The goal is not to be calm all the time. The goal is resilience — the ability to meet the demands of life and then gracefully return to center.