A new study that was published in February took a look at the question of whether stress can increase the rate of aging in living organisms. The researchers noted:
Individuals of the same age can differ substantially in the degree to which they have accumulated tissue damage, akin to bodily wear and tear, from past experiences. This accumulated tissue damage reflects the individual’s biological age and may better predict physiological and behavioural performance than the individual‘s chronological age.
To assess the impact of chronic stress on adult Eurasian blackbirds (Turdus merula) as a proxy for humans, the researchers exposed them to a combination of repeated immune and disturbance stressors for over one year. The researchers then took a look at several different markers that may indicate biological aging.
Measures of Aging
The biggest finding was that birds that were exposed to chronic stress showed greater decreases in the telomere length. Telomeres are sections of repeated nucleotides that act as disposable buffers at the end of chromosomes which get cut off during cell division. Telomeres get truncated off of a strand of DNA so that important sections of genes do not get cut off instead. Because this process is repetitive and reliable during cell division it can be used as a marker for aging. The longer the telomere, the more potential copies you have.
“If telomeres become too short, they have the potential to unfold from their presumed closed structure. The cell may detect this uncapping as DNA damage and then either stop growing, enter cellular old age (senescence), or begin programmed cell self-destruction (apoptosis) depending on the cell’s genetic background.” While there are mechanisms for replacing the telomeres, an easy-to-understand-over-simplification is that the shorter the telomeres, the older the organism and the fewer cell divisions they have left before it dies. This is why researchers can use it as a proxy for measuring aging.
Interestingly, the researchers found that other potential biomarkers like the concentrations of antioxidants and glucocorticoid hormones (stress hormones) did not differ significantly between the treatment and control groups. What they did find was a higher level of circulating oxidative damage in the stressed birds compared to the controls.
The researchers concluded “…that repeated exposure to experimental stressors affects the rate of biological ageing in adult Eurasian blackbirds. Both telomeres and oxidative damage were affected by repeated stress exposure and thus can serve as blood-derived biomarkers of biological aging.” In other words, repeated stress really can age you faster.
The dose makes the poison. We all need little stresses to support our health. The sun, phytochemicals in the plants we eat, exercise, and even a little fasting now and then are all healthful stresses that can actually improve your well being and help decrease your risk for chronic diseases, but too much or too often and the result is damage. Make an appointment today to discuss whether you’ve struck the right balance between healthful and harmful stress.