You can think of telomeres as aglets, those plastic tips on the ends of shoelaces, that keep your shoelaces (or DNA) from fraying. Instead of plastic, telomeres are composed of DNA nucleotides and proteins that bind to certain sequences of DNA that are prone to damage. In white blood cells, telomeres are ~8,000 base pairs in newborns, 3,000 base pairs in adults, and 1,500 in elderly people. Each time a cell divides, telomeres shorten by 30 – 200 base pairs, limiting cells to divide ~50 – 70 times before reaching critically low telomere length and undergoing programmed cell death.
Telomere shortening provides an internal clock and accounts for many processes associated with aging. Indeed, shorter telomeres have been associated with increased disease and mortality, most recently in a study that tracked 64,000 people and showed that longer telomeres = longer healthy lives.
On the flip side, the enzyme telomerase adds nucleotides to telomeres, blunting telomere shortening due to cell division or oxidative stress.
The framework of telomeres (summarized in this 25-year old article cited over 3000 times) was laid in the Nobel-prize winning work of Dr. Elizabeth Blackburn, who continues to be a reasearch baller at UCSF. Collaborating with a psychiatrist, Blackburn showed that perceived psychosocial stress shortens telomeres, reduces the telomerase activity, and increased oxidative stress. In fact, women with the highest perceived stress exhibited 10 extra years of cellular aging!
But don’t panic; Dr. Blackburn recently published a high-impact article showing that telomere length is not the sole readout for aging, but also the activity of telomerase, the enzyme that maintains telomeres on DNA. The new data from her research group showed that telomerase inactivation accelerates aging and decreases lifespan of yeast cells.
So telomere shortening is one way that time and stress ages you. On the flip side, lengthening telomeres has been shown to increase lifespan in cultured human skin cells.
So, how do you keep your telomeres long and functional to enable a long and happy life?
Per usual, the answer is simple, but not easy: prevent your telomeres from shortening more than necessary, and enhance the activity of telomerase, which will lengthen telomeres. Yes, there is a genetic component to telomere length and telomerase activity, but telomere length is largely under your control based on how you live. As no differences in telomere length have been found between male and female newborns, both genders are set up for long lives. Similarly, there have been no differences found among race and socioeconomic status in regards to telomere length, suggesting that we all can enjoy long telomeres.
Let’s learn a bit about telomerase to understand how to optimize its function.
Human telomerase is made of 3 subunits, encoded by genes (TERT, TERC, DKC1, and TEP1) that are located on different chromosomes. It’s commonly believed that telomerase is present only in fetal cells, germ cells (eggs and sperm), and, scarily, cancer cells (hence their immortality), but not most other cells. However, searching BioGPS, a consortium of primary research data, shows that telomerase-associated genes have been detected in several interesting tissues. For instance, TERT, which encodes telomerase reverse transcriptase, a subunit of telomerase, is expressed in the lungs, small intestines, brain, and in higher levels in the heart and skeletal muscles.
This gene map suggests that telomerase exists in several types of cells in adults. Perhaps the increased expression levels of TERT in hearts and skeletal muscle is one way that exercise keeps you young 🙂
Indeed, a 2016 study found that endurance athletes exhibit significantly longer leukocyte telomeres and upregulated expression level of key telomerase genes, TERT and TPP1, compared with age-adjusted controls. Resting heart rate was an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression – so you don’t need to get expensive telomere length tests to assess your telomeres, just a simple measure of your cardiovascular fitness. The lower your resting heart rate, the longer your telomeres. This study showed the impact of fitness in preventing biological aging, finding that moderate amounts of exercise was just as effective as high volume.
Another telomerase-associated gene, TERF1, exists at strikingly high levels in the brain, especially the prefrontal cortex, which is associated with higher level thinking and decision making.
Several positive effects of meditation on the prefrontal cortex have been shown, including increased cortical thickness in meditators and increased regional blood flow (and these beneficial blood flow patterns were also observed in people engaged in verbal prayer!). Given the TERF1 expression levels in brain regions associated with mindfulness, it stands to reason that meditation may activate this enzyme, increasing telomere length and thus the length of healthy lifespan 🙂
So, exercising and meditating optimize telomerase activity, enabling long telomeres that are associated with long lives.
As sleeping may be considered the best meditation, it’s no surprise that a recent study tracking the sleep of 434 middle-aged men found that those who slept 5 hours a night had telomeres that were 6% shorter than those who slept 7+ hours per night. Add quality sleep to your telomere maintenance protocol.
We know that many types of stress shorten telomeres and can exacerbate disease progression, and interestingly, the way you view the world affects your telomeres. Since pessimism has been linked to shorter telomeres (in men and women) (and other hyper-inflammatory conditions), I recommend maintaining realistic optimism as much as possible!
Similarly, more studies than I can list link chronic stress to shortened telomeres (and tons of other health problems); I’ll point out just one interesting study that showed that stressed caregivers to dementia/Alzheimer’s patients exhibited lower overall telomerase activity, but telomerase activity increased 18% when caregivers experienced an acute stressor. This study reinforces the importance of distinguishing between types of stress; chronic stress is generally unhealthy, while acute stressors (often called hormesis) make you stronger. Chronic stressors are things like hating your job, consistently eating processed foods, and staying in draining relationships, and hormetic/acute stressors include cold showers, sprinting, and eating spicy foods 🙂
Anyway, as we all know that stress ages you, do your best to manage chronic stress.
While molecular studies haven’t linked happiness to telomere length (yet!), existing evidence suggests that the well-being derived from exercise, meditation, low stress, nutritious food, stellar sleep, and fulfilling social connections keeps your telomeres long and DNA printing out the best versions of yourself. A motivating factor to prioritize my happiness for future mothers, like me, is this study that demonstrated that daughters of mothers with recurrent depression had shorter telomeres than their low-risk counterparts, and shorter telomere length is associated with greater cortisol reactivity to stress. Therefore, by ensuring my own happinesss, I’ll be setting up my children for longer lives and more productive reactions to stressors.
To recap, in order to maintain long telomeres for a lengthy, healthy life, do the following:
- exercise (which can buffer the telomere-shortening effects of chronic stress!)
- maintain fulfilling social connections
- aim for realistic optimism
- sleep like you’re getting paid for it
- meditate in whatever way works for you
- avoid drugs and cigarette smoking (kinda obvious, but wanted to be comprehensive!)
- eat real foods that nourish your body and spirit (and provide sufficient nutrients)
and of course, don’t neglect play!