In 2008, a study was published on the effects of meditation, specifically:
the first compelling evidence that the Relaxation Response (RR) – the physiological response to meditation, yoga, tai chi, Qi Gong or repetitive prayer – affects our genes.
Scientists analyzed blood samples, and concluded that 2209 genes were expressed differently (turned on or off) depending on if the participants were in the meditation group, or the control (non-meditation) group.
The genes which were analyzed were specifically involved in cellular metabolism and the body’s response to stress, known as ‘oxidative stress’ – this is why the body produces free radicals under stress, a known cause of disease and ageing at the cellular level.
The full study abstract is here.