Mindfulness Meditation

Mindfulness meditation is the practice of paying deliberate, non-judging attention to the present moment, usually taught as an 8-week course. Compared with doing nothing, it lowers distress by a small-to-moderate amount, and in one trial it eased diagnosed anxiety about as much as a standard antidepressant. It is not uniquely powerful, though: it does not clearly beat other active programs, its benefit for anxiety shrinks over the following months, and about 1 in 12 people who meditate report an unwanted effect.

If you want to try it, take a structured course, practise about 30 minutes most days for at least 8 weeks, and judge it on how you feel, not on any blood test. Stop or get help if it brings on anxiety, low mood or unusual thoughts.

What it is

Mindfulness means training attention on what is happening now, such as the breath or body sensations, and noticing thoughts without judging them. The best-studied formats are two teacher-led 8-week courses: Mindfulness-Based Stress Reduction (MBSR) and Mindfulness-Based Cognitive Therapy (MBCT); MBSR, the older of the two, has been studied for over four decades. The idea is that this kind of attention interrupts rumination, the loop of repetitive worrying thoughts, and may lower the steady output of the stress hormone cortisol. Whether it shifts the resting balance of the nervous system is unclear; see heart-rate variability (HRV).

This page holds the study-level detail; how mindfulness fits alongside exercise, sleep, slow breathing and relationships is on Stress.

It works, by a modest amount

In adults without a mental-health diagnosis, teacher-led mindfulness courses reliably lower psychological distress compared with doing nothing. The pooled effect was small-to-moderate, a standardised effect of 0.32 across 2,371 people in 13 trials ^[1].

Against other active programs the picture is more modest. Across 136 trials, mindfulness did not clearly beat other purpose-built active programs, so it is one good option among several rather than a uniquely powerful one ^[2].

A careful 2014 review that counted only trials with an active comparison found a small-to-moderate benefit for anxiety at 8 weeks (a standardised mean difference of 0.38), fading to 0.22 at 3–6 months. Effects on depression (0.30) and pain (0.33) were similar in size. The evidence for less stress was only low-strength, the evidence on mood, sleep and weight was low or insufficient, and there was no evidence that meditation beat any other active treatment ^[3].

Against a drug: holds its own

In 276 adults with a diagnosed anxiety disorder, an 8-week MBSR course reduced anxiety about as much as the antidepressant escitalopram. Side effects were far rarer: 15% of the mindfulness group had at least one study-related side effect, against 79% on the drug. Patients knew which treatment they got and there was no placebo group ^[4].

Why the big numbers you see are misleading

Much larger effects are sometimes quoted, close to a full standard deviation for anxiety and mood. Those come from before-and-after changes in patients with diagnosed disorders, with no comparison group, so they include everything else that improved over the same weeks. They are not the effect of mindfulness against a control ^[5].

Low-risk, not risk-free

Pooling 83 studies, about 1 in 12 meditators reported an unwanted effect, about 1 in 27 in experimental studies. The most common were anxiety, low mood and unusual thinking, and they sometimes occurred in people with no history of mental-health problems ^[6].

What it does in the body, and what it doesn't

Inflammation is the better-supported signal. Across 45 randomised trials that compared meditation with another active activity, meditation lowered C-reactive protein (CRP, a blood marker of inflammation), tumour necrosis factor-α (TNF-α, another inflammation signal), cortisol, blood pressure, heart rate and triglycerides ^[7]. A pooling of 48 randomised trials (4,683 people) found small drops in CRP and interleukin-6 (IL-6) at the end of mindfulness programs, with wide uncertainty for IL-6 ^[8]. A preregistered pooling of 32 randomised trials was more cautious: its effect on inflammation and stress markers only just missed statistical significance, and it warned that weak studies and selective publishing may have biased the results ^[9]. So expect a small drop in CRP at most. Whether trained people mount a smaller inflammatory response to an acute stressor has not been shown in pooled trials.

Telomeres, the protective caps on chromosomes, are a weaker story. In the most rigorous trial, 137 older adults were randomised to 18 months of meditation training, language training or no training, and meditation had no effect on telomere length ^[10]. A 2023 pooling of 25 studies (2,099 people) found a small benefit, but it came mainly from comparing experienced meditators with non-meditators, not from trials of meditation programs. Most studies were small, the authors saw signs of publication bias, and they concluded that telomere length "may not be a useful outcome" for these interventions ^[11]. Earlier positive pilots were small and often non-blinded. More on telomere attrition.

How much, and in what form

Dose. The studied dose is an 8-week course. In MBSR and MBCT courses people typically manage about 30 minutes a day, six days a week, roughly two-thirds of what is assigned, and how much people say they practise is only modestly linked to how much they benefit ^[12].

Retreats. A retreat is not wasted. Pooled studies of meditation retreats in the general population found moderate benefits overall, with larger effects on anxiety, depression and stress that were still present at follow-up, though the studies varied a lot ^[13]. Keeping up some daily practice afterwards is the sensible way to hold on to them.

Apps and sticking with it. Solo practice often fails because people stop. In real-world usage data on 93 popular mental-health apps, a median of only about 3% of users were still using an app 30 days after installing it, about 5% for meditation apps ^[14].

With a partner. In "contemplative dyads", two people take turns speaking and listening mindfully, about 12 minutes a day through an app, with weekly online coaching. In a 10-week randomised trial in 253 healthy adults, the partner practice reduced loneliness more than solo mindfulness training did ^[15], and people kept it up at least as well as solo meditation ^[16]. In 140 participants from the same project, tested after training, the partner group, but not the mindfulness group, had lower cortisol than an untrained control group during a lab public-speaking test, though they did not feel less stressed ^[17]. A related idea, pairs meditating in virtual reality while seeing each other's breathing, has so far measured only short-term effects such as feeling more "present" with a partner, and the review cites no data on sticking with it or on stress hormones ^[18]. This is early evidence, not yet ready to prescribe.

With exercise. Combining meditation with aerobic exercise is promising but rests on small pilots: in women with a history of sexual violence, meditation followed by aerobic exercise twice a week reduced rumination, while either alone did not ^[19].

What to do

Pick a structured course, MBSR or MBCT style, rather than relying on one-minute app sessions, which are well below the studied dose.
Give it 8 weeks at about 30 minutes most days before judging it.
Treat it as one option among several. If it doesn't suit you, slow breathing, exercise or another active program may do as much.
Watch for unwanted effects. If practice brings on anxiety, low mood or unusual thinking, ease off and talk to someone.
Don't buy it for your telomeres. The case for meditation rests on how you feel, not on a cellular aging marker.