12 Bienfaits scientifiquement prouvés de la méditation pour la santé

Dire que l'année a été stressante serait un euphémisme. Si vous ne méditez pas, vous avez peut-être envisagé de commencer pour calmer votre esprit, cesser de vous inquiéter et mieux dormir. Mais commencer une pratique de méditation peut être intimidant. Comment pouvez-vous l'intégrer à votre emploi du temps déjà chargé et comment savoir si vous le faites correctement ?

I’ll answer those questions in my next post, Comment faire de la méditation une partie de votre vie quotidienne. This week, I want to get you motivated to commit to a meditation practice, so I’m going to give you scientific proof of how meditation:

• Réduit le stress
• Améliore le sommeil
• Réduit la douleur
• Réduit l'inflammation systémique
• Abaisse la tension artérielle et le risque de maladies cardiovasculaires
• Réduit le risque de cancer
• Modifie la structure du cerveau
• Améliore la cognition
• Réduit les comportements addictifs
• Réduit les fringales et l'obésité
• Améliore la fertilité
• Augmente la longévité

1. La méditation réduit le stress.

L'une des raisons les plus courantes pour lesquelles les gens se tournent vers la méditation est de réduire leur stress, et les chercheurs explorent comment la méditation améliore non seulement le niveau de stress autodéclaré, mais aussi les biomarqueurs de stress. Heureusement, ils ont découvert que même de courts programmes de méditation avaient des effets positifs durables sur notre réponse au stress.

A 2007 study explored the effects of an eight-week mindfulness-based stress reduction (MBSR) program on early stage breast cancer and prostate cancer patients. At 6- and 12-month follow-ups, results showed significant improvements in overall symptoms of stress as well as levels of cortisol, a stress hormone.

A 2014 study of PsychoNeuroEndocrinoImmunology-based meditation (PNEIMED), which combines the teaching of philosophy and practice of Buddhist meditation with a grounding in human physiology from a systemic and integrative perspective, had similar results. After a four-day PNEIMED training, self-rated distress scores were greatly reduced, and the improvement of psychological well-being was accompanied by a decrease in cortisol levels. Another study evaluated the effects of an 8 week, 2-hr per week training in passage meditation on the stress level and mental health of health professionals. The meditation training improved both stress level and mental health, and the stress reductions remained large at the 19-week follow-up.

An interesting 2018 study found that after practicing MBSR daily for 21 days, glaucoma patients had significantly reduced levels of stress-biomarkers, including cortisol, intraocular pressure, Interleukin 6, reactive oxygen species, and tumor necrosis factor. They also had elevated β-endorphins, brain-derived neurotrophic factor, total antioxidant capacity, positive modifications in gene expression, and improved quality of life ratings.

2. La méditation améliore le sommeil.

En tant qu'ancien insomniaque, je ferais à peu près n'importe quoi pour améliorer la qualité de mon sommeil - et j'ai découvert que méditer avant de me coucher me permet de m'endormir beaucoup plus rapidement et facilement. C'est maintenant une partie non négociable de ma routine du coucher.

One reason why meditation makes it easier to fall sleep is that it increases alpha and theta waves in your brain. Instead of trying to shut your brain down from the active beta waves of wakefulness directly into the delta waves of sleep, meditation transitions you from beta, to alpha, to theta waves, making the transition to sleep happen more easily and naturally.

If you suffer from insomnia, you may have taken over-the-counter melatonin to help you get to sleep. Another reason why meditation improves sleep is because it significantly increases plasma melatonin levels in the period immediately following meditation. In addition, daytime melatonin levels have been found to be more than four times higher in Vipassana meditators than non-meditating controls.

And research shows that practicing mindfulness for just two hours per week for six weeks results in improvements in sleep quality as well as improvements in insomnia symptoms, depression symptoms, fatigue interference, and fatigue severity.

3. La méditation réduit notre perception de la douleur.

When our physical body is injured or at risk of being injured, pain receptors send a message up the spinal cord to let our brain know. Then, the unpleasant experience of pain is created by a perceptual process involving the emotional parts of our brain. An ancient Buddhist text states that meditation practitioners are able to experience the sensory aspect of pain without the unpleasant emotional reaction that typically accompanies it. Recently, scientists have begun examining how meditation may stimulate the release of endogenous opioids, naturally relieving pain, as well as alter how emotional parts of the brain respond to pain.

Studies of long-term Zen meditators and vipassana practitioners have found that while their pain intensity ratings are in the normal range, they report significantly lower pain unpleasantness ratings than non-meditators. These results correlate with brain scans showing reduced activation in brain areas that process the emotional experience of pain.

Good news for the rest of us—even short-term meditation practice can produce similar results. After just four 20-minute sessions of mindfulness meditation, healthy volunteers experienced a 40% reduction in pain intensity and a 57% reduction in pain unpleasantness. Brain scans showed increased activation in areas involved in analgesia (pain relief), and also showed evidence that meditation may help to block pain information being sent from the peripheral nerves to the brain.

Another study of long-term meditators found a correlation between meditation, brain volume, and pain perception. Long-term Zen meditators were found to be significantly less sensitive to pain, and this lower pain sensitivity correlated with a thicker cortex in pain-related regions of the brain.

Si vous voulez faire une exprience, et s'il vous plaît, ne vous blessez pas, essayez ceci :

Ferme tes yeux. Prenez une ou deux respirations lentes et profondes dans le bas de votre ventre et détendez-vous complètement.

Prenez un pouce et enfoncez votre ongle dans le pouce ou un doigt de votre main opposée. Quand ça commence à faire assez mal pour que tu veuilles arrêter, ne t'arrête pas. Gardez les yeux fermés, continuez à respirer profondément dans votre ventre (pas dans votre poitrine !) et détendez-vous autant que possible. Abandonnez la réaction émotionnelle et stressante que vous auriez normalement face à cette sensation douloureuse. Remarquez cette sensation douloureuse, mais essayez de vous détendre et de ne pas y réagir. Pouvez-vous sentir en quoi cela est différent de la façon dont vous réagiriez normalement à la douleur ?

4. La méditation réduit l'inflammation systémique.

Nearly every chronic disease has been linked to systemic inflammation, so we all want to do what we can to reduce it. An important 2016 study showed that a three-day intensive mindfulness meditation program improved the functional connection between the default mode network and the dorsolateral prefrontal cortex in the brain. This improved connection resulted in improved levels of Interleukin 6 (IL-6), a biomarker of systemic inflammation, four months after the mindfulness program. And a 2013 study found that an eight-week mindfulness-based stress reduction (MBSR) program resulted in a significantly reduced inflammatory response.

Meditation even alters our DNA. A 2017 meta-analysis found that mind-body practices reduce the activity of genes related to inflammation by downregulating the nuclear factor kappa B pathway. The authors note that mind-body practices have the opposite effect on genetic activity as chronic stress, which increases inflammation, so these practices may reduce the risk of inflammatory diseases.

5. La méditation abaisse la tension artérielle et réduit le risque de maladies cardiovasculaires.

A study of 111 men and women aged 55 to 85 years found that Transcendental Meditation (TM) lowered both systolic and diastolic blood pressure significantly. A meta-analysis found that TM reduces blood pressure to a degree similar to other lifestyle interventions such as a weight-loss diet and exercise.

Research also shows that contemplative meditation combined with breathing techniques lower blood pressure by an average of 18 mm Hg, compatible with a nearly twofold decrease in risk of death from cardiovascular disease. In 2017, the American Heart Association released a scientific statement recommending that meditation may be used in clinical practice for cardiovascular disease.

6. La méditation diminue le risque de cancer.

Studies show that meditation lowers cancer risk by strengthening the immune system and reducing inflammation. A 2017 study of breast cancer patients found that an eight-week program in mindfulness-based stress reduction (MBSR) significantly increased NK-cell (natural killer cell) activity and improved lymphocyte counts. A study of breast and prostate cancer patients showed that an eight-week MBSR program led to reduced levels of Th1 (pro-inflammatory) cytokines both after the program and 6 and 12 months later.
A review of 165 studies found that stress increases cancer incidence and mortality, so reducing stress is likely another way in which meditation helps to lower cancer risk.

Another way in which meditation likely reduces cancer risk is by increasing melatonin production. Melatonin deficiency weakens the immune system, making us more susceptible to cancer. Melatonin is an antioxidant and free radical scavenger, and plays an important role in our innate immune system, our first line of defense against attack. Melatonin can inhibit growth of cancerous tumors, and may help prevent breast cancer, prostate cancer, gastric cancer, and colorectal cancer. It also protects healthy cells from radiation-induced and chemotherapy-induced toxicity, so it can be used as an adjuvant of cancer therapies.

7. La méditation modifie la structure de votre cerveau.

A number of studies (Lazar 2005, Kang 2013, and Grant 2010) have compared the brain structure of experienced meditators to non-meditators. They consistently find that long-term meditation practice leads to increased thickness in many areas of our brain’s cortex—that means more gray matter, more brain power, better emotional regulation, and improved cognition as we age.

A 2012 study found that the volume of the hippocampus was significantly larger in long-term meditators. The study authors suggest that the increased size of the hippocampus may be one explanation for the cognitive skills, mental capacities, and personal traits associated with the practice of meditation. They also suggest that the increase in hippocampal size may be the result of meditation-induced stress reduction.

8. La méditation améliore les capacités cognitives.

In a 2010 study, researchers tested the effects of an eight-week meditation program on 14 subjects with memory loss problems. They found that meditation improved verbal fluency and logical memory, and significantly increased cerebral blood flow to the prefrontal, superior frontal, and superior parietal cortices. Another study tested the effects of Transcendental Meditation (TM) on 73 adults with an average age of 80 years who had normal to poor cognitive functioning, and found that those who practiced TM three times per week for 12 weeks had significantly improved scores on verbal and learning tests.

Numerous other studies have found that meditation improves sustained attention; visuo-spatial processing, working memory, and executive functioning; and that even short meditation practices result in immediate improvements in cognition.

9. La méditation réduit les comportements addictifs.

A 2016 study used brain scans to observe the effects of a brief mindfulness training (Integrative Body-Mind Training, IBMT) in smokers and non-smokers. In both groups, the training improved self-control abilities in emotional regulation and stress reduction, and these changes were related to increased activity in the anterior cingulate cortex and adjacent prefrontal cortex. Compared with non-smokers, smokers showed reduced activity in the self-control network before training, and the mindfulness training ameliorated these deficits.

Another study found that just two weeks of meditation training resulted in a 60% decrease in smoking among regular smokers. Like the other study, this one found that meditation increased activity in the anterior cingulate and prefrontal cortex, brain areas related to self-control. Evidence for the efficacy of mindfulness training in treating substance use disorders continues to accumulate, and researchers are examining the complex neurocognitive mechanisms involved so that these trainings can be used more often in clinical settings.

10. La méditation réduit les fringales et l'obésité.

Mindfulness-based approaches are becoming more widely used as interventions for eating disorders and weight loss. A review of 14 studies found that mindfulness meditation decreases binge eating and emotional eating. And a study of 14,400 men and 49,228 women found that those who scored higher on a mindfulness scale were less likely to be overweight or obese.

A 2016 study examined the effect of meditation experience and food-specific decentering experiences on food cravings. “Decentering refers to viewing one’s thoughts as transient mental events and thus experiencing them as less subjectively real.” We can use decentering to simply observe a food craving as a mental event that will pass, rather than as an actual physical need to eat a certain food. The study found that both more meditation experience and more food-specific decentering experiences were associated with fewer food cravings in daily life.

11. La méditation améliore la fertilité.

A 2016 study of women undergoing in vitro fertilization tested the effects of a mindfulness-based intervention, and found that the intervention significantly increased pregnancy rates. This may have been because meditation reduced stress and/or helped balance hormone levels. In men, meditation and yoga increase sperm motility and sperm count, and reduce DNA fragmentation.

And a note for expecting moms: A 2014 study found that babies born to women who meditated while pregnant had better health at birth and better temperaments at five months old.

12. La méditation augmente la longévité.

One important way in which meditation lengthens our lives is by reducing our stress; stress increases the risk of all chronic diseases, including heart disease and cancer. A study of long-time Transcendental Meditation (TM) practitioners found they had a 30% lower risk of death from cardiovascular disease and 49% lower risk of death due to cancer than controls. And a study of residents of homes for the elderly, with an average age of 81 years, tested the effects of TM, mindfulness training, and relaxation training on longevity. At a three-year follow-up, the survival rate was 100% for those who had practiced TM and 87.5% for those who had practiced mindfulness, in contrast to lower rates for those who had practiced relaxation or had no intervention.

Another way in which meditation lengthens our lifespan is by increasing telomerase, an enzyme that protects chromosomes and is related to the speed of the aging process. As our chromosomes age, cell reproduction reduces the length of telomeres, the protective endcaps on chromosomes. When telomeres eventually disappear, cells stop replicating. More telomerase equals longer telomeres and a longer lifespan. In one study, participants in a three-month meditation retreat were found to have 30% more telomerase than controls. Another study found that people who practiced the Buddhist-derived Loving-Kindness Meditation had longer telomeres than people who had never practiced meditation. Chronic stress is a factor here as well; research shows that chronic stress shortens telomeres, allowing our cells to die off sooner.

Finally, meditation increases the transcriptome factor REST, which regulates neural excitability and extends longevity. More REST equals a longer lifespan. A study of 81 older adults with psychiatric risk factors for Alzheimer’s Disease found that a mindfulness-based stress reduction intervention caused an increase in REST and a decrease in psychiatric symptoms. Not surprisingly, chronic stress reduces REST, which shortens lifespan.

Nous pouvons parler toute la journée des bienfaits de la méditation, mais comme toute méthode de soins personnels, nous n'en récolterons les bénéfices que si nous le faisons réellement. Dans un prochain article, je discuterai des différents types de méditation et de la façon de commencer si vous êtes débutant - c'est plus facile que vous ne le pensez !