Researchers believe sex may aid ageing in women by dampening stress and boosting their immune system.
How the study was carried out
Researchers from the University of California in San Francisco analysed physical intimacy, as well as partner support or conflict, overall relationship satisfaction and stress in 129 mothers in long-term relationships.
Blood samples were taken from the study's participants to determine their telomere length.
The study was conducted over one week.
Key findings
Results revealed that women who had sex at least once during the study's one-week duration had significantly longer telomeres.
Relationship satisfaction, stress and partner support or conflict had no impact on telomere length.
The findings were published in the journal Psychoneuroendocrinology.
Telomeres 'cap' the ends of DNA strands. They shorten with age and poor lifestyle habits, such as alcohol abuse, however, being active lengthens them.
Previous studies have linked longer telomeres to reduced ageing, improved overall health and a longer lifespan.
Lead author Tomás Cabeza de Baca said: "Over time, shortened telomeres may contribute to chronic degenerative diseases and premature mortality.
"Sexual intimacy may dampen the effects of stress by down-regulating stress response systems and up-regulating immune response.
"Over time, these patterns of stress function should result in longer telomere length," PsyPost reported.
The effects of regular sex in men are unclear.
Sex prevents heart disease - but only in men
Regular sex really is the best medicine for preventing life-threatening heart disease - if you are a man, scientists found last month.
Research reveals making love several times a week can slash levels of homocysteine - a harmful chemical in the blood that can trigger cardiac problems.
It is thought men who have sex often have better circulation and healthier blood vessels. This is crucial for preventing a build-up of homocysteine.
Yet scientists say women benefit much less because sexual arousal is not as dependent on having a healthy blood flow, which is a key factor in keeping homocysteine under control.
Researchers from the National Defence Medical Centre in Taiwan have called on doctors to advise male patients at risk of heart disease to have more sex.
