Reviewing Associations Between Physical Activity and Loss of Average Telomere Length with Age

Telomeres are repeated DNA sequences at the ends of chromosomes. With each cell division a little telomere length is lost, and this is an important part of the countdown mechanism that limits replication of somatic cells. Somatic cells with short telomeres become senescent or self-destruct. Stem cells, on the other hand, use telomerase to lengthen their telomeres, and thus produce daughter somatic cells with long telomeres throughout a lifetime. This two-tier system of privileged stem cells and limited somatic cells, present in near all animals, keeps the risk of cancer low enough for evolutionary success, while still allowing for tissue maintenance and cell turnover. Average telomere length in tissues declines with age, and this is largely a function of loss of stem cell activity. There are fewer replacement cells with long telomeres. Telomere length is usually measured in immune cells in a blood sample, however, and here there are many more factors at work to muddy the waters. Immune cells will replicate at quite different rates from day to day, depending circumstances ranging from stress to infection. In human studies, telomere length only exhibits associations with aging - or with interventions known to modestly slow aging - in the statistics of large groups. Even then many studies fail to find a good correlation with diet, exercise, and the like. Thus for any given individual there usually isn't much to learn from a measure of telomere length, or a change in that ...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs