The Scientific Evidence behind the Benefits of Meditation
1. The scientific evidence that meditation has benefits to
health and well-being:
Sara Lazar (neuroscientist and Harvard University researcher), has demonstrated that meditation benefits health and well-being through using MRI brain scans. In one study, participants took an 8 week mindfulness based stress reduction program, including daily meditation. MRI scans were used two weeks before and two weeks after the study. The participants reported a reduction in stress, which tied in with the decrease in grey matter shown in their amygdala. This part of the brain governs the fight or flight stress response. This indicates that even though the participants’ environment and outside stressful situations had not changed, the brain had adapted to cope better.
Many research studies have been conducted on TM Meditation. One study showed that teachers of students with severe behavioural problems reported a significant reduction in stress and workplace burnout symptoms after learning to practise TM Meditation.
Researchers at Lanzhou University’s Evidence-Based Medicine Centre in China used a meta-analysis to conclude that TM meditation can reduce blood pressure. The American Heart Association have also found that TM Meditation can have a positive effect on hypertension.
Scientific studies have also shown that those practising the well-known Buddhist Loving-Kindness meditation increased grey matter in the medial frontal cortex and the insular (a region deep in the cerebral cortex), revealing this region to be strengthened. These parts of the brain are associated with positive emotion, compassion and happiness.
In 2016, a study conducted by the Carnegie Mellon Universtity took a group of stressed adults and put half of them through a 3 day mindfulness meditation retreat. The other half went on a 3 day relaxation retreat (that didn’t include any mindfulness meditation).
Blood samples and brain scans were taken before and after the retreat, as well as at a 4 month follow up.
The results revealed that the participants who learnt the mindfulness meditation showed a significant reduction in the level of the inflammation bio marker, interleukin-6, indicating that the level inflammation in their bodies had reduced.
The brain scans also illustrated a strengthening in the part of the brain associated with stress resilience.
2. The techniques that can be used to demonstrate the
physiological changes in the brain:
An MRI, or magnetic resonance imaging machine, was first used to study the brain during meditation in the year 2000 by researcher Sara Lazar. She created a detailed brain map of the changes made from meditation. An MRI uses strong magnetic fields and radio waves to show an intricate image of inside the body.
The EEG, or Electroencephalography, was first used to study the brain during meditation in the 1970’s by researchers Barry Sterman and Joe Kamiya. This technique involves placing electrodes (small sensors) on the scalp to study and record the brain’s electrical signals. This is a painless technique. These electrical signals are called brainwaves, and are measured in cycles or by the number of times the neurons fire per second.
The first meditation study using rCBR, or regional cerebral blood flow, was in 2001 by neuroscientist Andrew Newberg. He used single photon emission computed tomography (SPECT) to measure changes in rCBR during the practice meditation of Tibetan monks.
3. How brain waves are altered in a meditative state:
Brainwaves are the organised electrical activity in the brain. They are measured by an EEG.
Our brainwaves are frequently changing and different parts of the brain are often associated with the different brainwaves. When we are awake, alert and experiencing our usual daily activities, our brain is in Beta waves. This includes when we are feeling stressed or anxious. These are fast waves, between 13 and 30 Hz (or cycles per second).
During meditation, when we close our eyes and are in a state of ‘relaxed wakefulness’, (focusing on the present moment and also feeling relaxed) our brainwaves slow down. Our brain moves into Alpha waves. These are a moderate wave speed, between 8 and 12 Hz.
When we go into a deep meditation, our brainwaves slow down further into Theta waves. This tends to be when meditators experience a sense of bliss during their practice. Alpha waves are also associated with being in a creative flow state. Interestingly, children between the ages of 2 and 5, experience mostly Theta brainwave states as they are able to focus on creative play and have a strong imagination. Theta waves operate at a slow speed, between 4 and 8 Hz. When we are asleep, the brain moves into Delta waves, which are the slowest brainwave. Delta waves operate between 0.5 and 4 Hz.
Gamma waves are interesting. We move into this very fast brainwave state when we are in a super focused flow and at our peak performance. The activity in the brain fires much more cohesively and works as one. When we are in this state of coherence, we can access more of our potential. We usually only experience gamma waves for a short period of time (often less than a second). These are very fast brainwaves, between 30 and 100 Hz (or cycles per second).
Scientific research conducted by neuroscientist Richard Davidson showed that very advanced level meditators (such as Tibetan monks) showed that their brains were operating in gamma waves most of the time, no matter what they were doing. These gamma waves increased by 700 percent within a few seconds after starting a meditation focused on kindness and compassion. This is often called the ‘state of enlightenment’.
4. The physiological changes in the body associated with
meditation:
In 2005, Sara Lazar (neuroscientist and Harvard University researcher) conducted a study that showed that long term meditators had significantly thicker tissue in their pre frontal cortex.
This area is associated with cognitive processing, memory and decision making.
This part of the brain naturally shrinks as we get older, correlating with memory decline.
The study also revealed that the 50 year old meditators had the same amount of cortical thickness as 25 year old non-meditators, indicating that long term meditation may slow down brain ageing.
Another interesting study conducted by Jon Kabat-Zinn at Massachusetts Medical Centre showed that participants boosted their immune system by producing more antibodies to a vaccine (than the control group) after an 8 week meditation course.
Other regions of the brain that have been shown to positively change in structure include:
the Hippocampus (responsible for emotional regulation and memory), and
the Hypothalamus (responsible for regulating body temperature, blood pressure and hunger).