Meditation slows down aging on a cellular level. A commonly used sign of cellular aging is the length of our telomeres. Telomeres are a compound structure at the end of a chromosome. Shorter telomeres are correlated with diseases such as hypertension, cardiovascular syndrome, diabetes, and senility. A study discovered that immune cell telomere length actually rose in a group of people during an intensive meditation retreat. Another study found that trained Zen meditators have longer telomeres overall. And they showed a smaller percentage of short telomeres than the average person in a similar age and comparable lifestyle.
Source: Deepak Chopra on Youtube