Meditation Can Change Body’s Response to Stress

Many studies show meditation can reduce stress. Yet most studies have relied on subjective 
measurements of stress, such as self-reports. Little research has quantified how much 
meditation can reduce stress. New research by the U.S. Army Research Laboratory and the 
University of North Texas seeks to change this.

Researchers spent a year developing a novel stress-measurement strategy. The technique 
uses the heartbeat irregularities to assess stress levels in the brain. The study, 
published in Frontiers in Psychology, found long-term meditation can induce permanent 
physiological changes. Meditation may alter the way the body responds to stress.

Measuring Stress in the Brain Through Heartbeats
Monitoring changes in the brain can be difficult. The study used a new method, dynamic 
subordination technique (DST), to process these tiny changes. DST uses heart rhythms to 
measure stress levels in the brain and nervous system.

A normal heartbeat has slight irregularities. The time interval between heartbeats can shift 
along a spectrum. The shifts are often due to input from the nervous system (especially the brain).

The sinus node is often called “the heart’s pacemaker” because it regulates heartbeat. 
It is controlled by two systems in the body:
1. The sympathetic nervous system, which activates during stress. It causes the sinus 
   node to fire faster.
2. The parasympathetic nervous system, which calms the body down (and may activate 
   during meditation). It causes the sinus node to fire slower.

Competing impulses from these systems cause the slight irregularities in a 
person’s heartbeat.

Researchers measured the level of variation in heartbeats before and during meditation. 
This number shows how much meditation reduces stress in the brain.

Can Meditation Change the Brain?
Researchers used DST to compare two forms of meditation:
1. Chi meditation: Participants visualized a lotus opening and closing within 
   their stomach. Individuals breathed spontaneously.
2. Kundalini Yoga: Participants did a sequence of breathing and chanting 
   exercises while sitting cross-legged.

Both types of meditation were shown to reduce stress in the body. 
Researchers found Kundalini Yoga offered greater reductions in stress. The structured 
breathing in Kundalini Yoga may contribute to the differences between meditation forms.

Long-term meditation in either form made the reductions in stress permanent. Long-term 
meditators also showed improvements in executive function. These changes might help a 
person better cope with external stressors. The Army hopes to use meditation to reduce 
posttraumatic stress (PTSD) in soldiers.

The study says more research is needed on meditation and stress. (This call includes 
research on the effectiveness of DST as a measurement of brain changes.) For now, the 
data support the idea that meditation-related stress relief is linked to physiological 
changes.

Several approaches to therapy incorporate elements of mindfulness or meditation. 
One example is mindfulness-based cognitive therapy (MBCT). MBCT aims to increase 
mindfulness as a way of changing behavior and making harmful thoughts less frequent.