It has long been known that stress can affect the immune system and now researchers at UCLA in the US have found out one of the ways in which this might happen. Every cell contains a tiny clock called a telomere, which shortens each time the cell divides. Short telomeres are linked to a range of diseases including HIV, osteoporosis and heart disease. When people experience stress the body boosts production of cortisol which helps with the 'fight or flight' response. Cortisol suppresses telomerase an enzyme which immune cells produce that maintains the length of their telomeres.
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