Meditation, an ancient mind and body practice, is used by around 18 million adults in the US.
Meditation is an ancient mind and body practice that is estimated to date back as far as 5,000 BCE. It is believed meditation originated in India, with the earliest documented records of the practice deriving from the teachings of Vedantism - an ancient Hindu philosophy.
In general, meditation involves training the mind to induce a state of consciousness that promotes a sense of serenity and increased concentration.
While meditation was traditionally practiced to induce a deeper religious and spiritual understanding, it has evolved to become a popular method of relaxation and stress reduction.
According to the National Center for Complementary and Integrative Health (NCCIH) - part of the National Institutes of Health (NIH) - meditation is practiced by around 18 million adults in the US, or 8% of the population.
Types of meditation
There are numerous forms of meditation, though most fall into four groups: concentrative, open awareness, mindfulness and guided meditation.
Concentrative meditation involves focusing the mind on a single object, such as an image, sound or breathing; Transcendental Meditation is one of the most common forms, in which the practitioner sits comfortably with their eyes closed for 20 minutes twice daily.
Open-awareness meditation, also referred to as non-directive meditation, aims to induce a sense of awareness without focusing on a specific object. Instead, the practitioner embraces all feelings and sensations that arise. Zazen - a Zen sitting practice - is a common form of open-awareness meditation.
Mindfulness is the most common form of meditation in the Western world; it combines both concentration and open awareness. In mindfulness meditation, the practitioner focuses on an object, such as sounds, bodily sensations, feelings, thoughts or breathing. Mindfulness is not as restrictive as concentrative meditation; the practitioner can focus on more than one object at a time.
Guided meditation involves the use of imagery, sounds and/or in-person guidance in order to induce a serene state of mind. Any form of meditation can fall into this category.
Meditation is commonly used to reduce anxiety and stress, but increasingly, researchers have found the benefits of meditation may have a much wider reach.
The potential benefits of meditation
Reduced brain aging and better memory
Since a key focus of meditation is to induce a tranquil state of mind, it is perhaps no surprise that researchers have found the practice yields brain benefits.
Earlier this year, a study reported by Medical News Today suggested meditation may reduce brain aging.
Studies have suggested that meditation may reduce brain aging.
The study of 100 individuals aged 24-77 - of whom 50 were meditators - found that those who engaged in meditating showed reduced gray matter loss in certain brain regions, compared with non-meditators.
Another study, published in the Journal of Alternative and Complementary Medicine in 2012, suggested that mantra-based meditation - a form of concentrative meditation in which a word, phrase or sound is repeated to prevent distracting thoughts - may help older individuals with memory loss.
The researchers, from Thomas Jefferson University Hospital in Philadelphia, PA, found that 12 minutes of mantra-based meditation daily for 8 weeks increased cerebral blood flow to the prefrontal, superior frontal and superior parietal cortices of 12 older adults with memory problems and improved their cognitive function.
While it remains unclear exactly how meditation affects the brain, researchers are getting closer to finding out.
Last year, MNT reported on a study in which researchers found individuals showed higher brain activity in brain regions associated with processing self-related thoughts, feelings and memory retrieval when they practiced Acem meditation - a form of open-awareness meditation - compared with when they were resting.
However, when the same participants practiced concentrative meditation, their brain activity in these regions was the same as when they were resting. This, according to the researchers, suggests that open-awareness meditation allows greater processing of memory and emotions than concentrative meditation.
Chronic pain - defined as pain lasting at least 12 weeks - is one of the leading causes of disability in the US, affecting around 100 million Americans. The most common types of pain include low back pain, severe headache or migraine and neck pain.
While medications such as opioids are commonly used to treat pain, studies have increasingly suggested meditation could be an effective pain reliever.
Last year, a study led by the Wake Forest Baptist Medical Center in Winston-Salem, NC, found an 8-week mindfulness-based meditation program that incorporated yoga reduced the frequency and severity of migraines; those who completed the program had 1.4 fewer migraines a month.
More recently, a study published in the Journal of Neuroscience last month - also by researchers from Wake Forest Baptist Medical Center - found that individuals who engaged in mindfulness meditation showed a 44% reduction in emotional response to physical pain and a 27% reduction in pain intensity.
Further investigation using brain imaging revealed that mindfulness meditation reduced participants' pain by activating the orbitofrontal and anterior cingulate cortex brain regions, which play a role in self-control of pain.
"Based on our findings, we believe that as little as four 20-minute daily sessions of mindfulness meditation could enhance pain treatment in a clinical setting," said lead author Fadel Zeidan.
With today's hectic lifestyles, it is no wonder so many of us have problems sleeping; around 50-70 million people in the US have some form of sleep disorder. But could meditation help? Some researchers think so.
In February this year, a study reported by MNT found that mindfulness meditation improved the sleep quality of older adults; more than half of American adults aged 55 and older have problems sleeping.
Published in JAMA Internal Medicine, the study revealed mindfulness meditation 2 hours a week for 6 weeks reduced Pittsburgh Sleep Quality Index (PSQI) scores among the adults from 10.2 to 7.4, compared with a reduction from 10.2 to only 9.1 for those who completed a sleep hygiene education program.
On the next page, we look at how meditation may benefit heart health, help quit smoking, and why health professionals say more of us should take up the practice.