Anyway, there is some new research just published that
Vigorous physical activity appears to protect those experiencing high stress by buffering its relationship with telomere length.Chronic psychological stress is responsible for a range of health problems, but it seems that it even has an effect at a cellular level right in the DNA. Exercise however can reduce its negative impacts:
In the study, 62 post-menopausal women – many of whom were caring for spouses or parents with dementia -- reported at the end of each day over three days the number of minutes of vigorous physical activity in which they had engaged. Vigorous activity in the study was defined as "increased heart rate and/or sweating.'' They also reported separately their perceptions of life stress that they had experienced during the prior month. Their blood's immune cells were examined for telomere length.
Results support the UCSF-led discovery six years earlier in premenopausal women that psychological stress has a detrimental effect on immune cell longevity, as it relates to shorter telomeres. The new study showed, however, that when participants were divided into groups – an inactive group, and an active group (i.e., they met federal recommendations for 75 minutes of weekly physical activity) – only the inactive high stress group had shorter telomeres. The active high stress group did not have shorter telomeres. In other words, stress predicted shorter telomeres in the sedentary group, but not in the active group.
There is more in the report here.