Telomeres are the end of a strand of your DNA – specifically a nucleotide sequence at the end of your chromosomes that protects them from deterioration or from fusing with neighboring chromosomes. The word “telomere” comes from the Greek, “telos” meaning end, and “meros” meaning “part.” You could say that this end cap of our DNA is essential to your health, but telomeres are also directly indicative of your total lifespan. 
A recent study found that shortened telomeres are associated with more age-related diseases like cancer, heart disease, diabetes, and more.  Longer telomeres seem to indicate the overall health of DNA, and some studies go so far as to say that telomere length can predict lifespan to within a year or two. 
Armed with this information, it is good to know that specific life style changes can alter your telomere length, and thus likely prolong the duration and quality of your life. Mediation, in particular, has been proven to have this positive effect.
Findings published in the journal Mindfulness have found that after measuring the length of telomeres in a group of 20 Zen meditation experts, and 20 healthy individuals in a control group, those who meditated had healthier telomeres:
“. . . We also measured multiple psychological variables related to meditation practice. Genomic DNA was extracted for telomere measurement using a Life Length proprietary program. High-throughput quantitative fluorescence in situ hybridization (HT-Q-FISH) was used to measure the telomere length distribution and the median telomere length (MTL). The meditators group had a longer MTL (p = 0.005) and a lower percentage of short telomeres in individual cells (p = 0.007) than those in the comparison group.” 
It is well known in yogic circles that those who practice yoga and meditation have a tendency to have lower biological age markers – meaning that they tend to age more slowly. The fact that they are meditating (as well as lowering stress in many cases through breathing, slow movement and other yogic practices) augments the science behind telomere length. 
So how much meditation (or other lifestyle changes) is needed to positively affect telomer length and slow cellular aging? So far, only studies on long-term meditators have been completed, but considering the recent studies that meditation starts to alter your grey matter within 8 short weeks, it is likely that similar changes can be found throughout our genetic makeup. 
To add meditation to your every-day life, start with just a ten-minute session in the morning and in the evening, and increase the time as you grow more accustomed to sitting in silence.
 Telomere. (2002, June 3). Retrieved from https://en.wikipedia.org/wiki/Telomere
 Shammas, M. A. (2011). Telomeres, lifestyle, cancer, and aging. Current Opinion in Clinical Nutrition and Metabolic Care, 14(1), 28-34. doi:10.1097/mco.0b013e32834121b1
 Telomeres and Telomerase: Their Implications in Human Health and Disease: Part 3: Stress, Telomeres and Telomerase in Humans (45:58). (2009). SciVee. doi:10.4016/10325.01
 Alda, M., Puebla-Guedea, M., Rodero, B., Demarzo, M., Montero-Marin, J., Roca, M., & Garcia-Campayo, J. (2016). Zen meditation, Length of Telomeres, and the Role of Experiential Avoidance and Compassion. Mindfulness, 7(3), 651-659. doi:10.1007/s12671-016-0500-5