What happens when you meditate?
If you’ve ever meditated, you know how it makes you feel—the intense relaxation and deep calm that suffuse you. But what physiological changes are occurring in your body and brain as you breathe deeply and focus your mind?
The answer centers on your autonomic nervous system, which controls various bodily functions. The autonomic nervous system is divided into two parts. The sympathetic nervous system directs your body’s response to stressful or dangerous situations, first described by Harvard physiologist Walter Cannon as the “fight-or-flight system.” When you’re confronted with, say, a vicious-looking dog, your sympathetic nervous system kicks into action. It increases your heart rate, boosts your blood pressure to send more blood to your muscles, and quickens your breathing, preparing your body to fight or flee.
When you meditate, you turn down your sympathetic nervous system and turn up your parasympathetic nervous system. This is the second part of your autonomic nervous system, which generally takes over once a danger has passed. It quiets your body and returns your heart rate, blood pressure, and breathing to normal.
Meditation also affects your brain’s electrical activity, otherwise known as brain waves. There are five types of brain waves: beta, alpha, theta, delta, and gamma. Beta waves are the most prevalent type when your brain engages in mental activities, such as conversing or teaching a class. Theta waves reflect the state between wakefulness and sleep and relate to the subconscious mind, creativity, and learning. Electroencephalogram (EEG) studies show that when you meditate, theta waves surge as your brain enters a state of deep relaxation. Interestingly, research has found that theta waves decrease in first-time meditators. This opposite reaction might reflect a state of increased alertness in people who are just learning the practice.