MEDITATE

Monks have been meditating on mountaintops for millennia, hoping to gain spiritual enlightenment. Their efforts have probably enhanced their physical health, too.

Trials looking at the effects of meditation have mostly been small, but they have suggested a range of benefits. There is some evidence that meditation boosts the immune response in vaccine recipients and people with cancer, protects against a relapse in major depression, soothes skin conditions and even slows the progression of HIV.

Meditation might even slow the ageing process. Telomeres, the protective caps on the ends of chromosomes, get shorter every time a cell divides and so play a role in ageing. Clifford Saron of the Center for Mind and Brain at the University of California, Davis, and colleagues recently showed that levels of an enzyme that builds up telomeres were higher in people who attended a three-month meditation retreat than in a control group (Psychoneuroendocrinology, vol 36, p 664).

As with social interaction, meditation probably works largely by influencing stress response pathways. People who meditate have lower cortisol levels, and one study showed they have changes in their amygdala, a brain area involved in fear and the response to threat (Social Cognitive and Affective Neuroscience, vol 5, p 11).

One of the co-authors of Saron's study, Elissa Epel, a psychiatrist at the University of California, San Francisco, believes that meditation may also boost "pathways of restoration and health enhancement", perhaps by triggering a release of growth and sex hormones.

If you don't have time for a three-month retreat, don't worry. Imaging studies show that meditation can cause structural changes in the brain after as little as 11 hours of training. Epel suggests fitting in short "mini-meditations" throughout the day, taking a few minutes at your desk to focus on your breathing, for example: "Little moments here and there all matter."

Jo Marchant is a freelance writer based in London