"Scientists have found you can hold back the hands of time with a regular romp," is The Sun's typically colourful headline.
While a healthy sex life may be a good thing, the research in question isn't exactly mind blowing.
The study included 129 mothers from San Francisco, half of whom had a child with an autism spectrum disorder (ASD) and were considered to have high stress levels.
The researchers wanted to assess the quality of these women's intimate relationships. Over a one-week period, they asked the women about their sex life and took blood samples to measure telomere length. Telomeres are the protective tips on the ends of our chromosomes that shorten as we age.
Overall they found that having sex in the past week was linked with increased telomere length that week.
The length of telomeres has been linked with being "genetically young" as longer telomeres may help protect against cell damage. But this association between telomere length and "youthfulness" has never been definitely proven.
Overall, this one-off assessment proves very little. It didn't look at how telomere length changed over time. And more importantly the longer term nature and quality of the relationship was not studied.
Even if there was a proven link between telomere length and a person's sex life, how this affects appearance and vitality is another matter.
The study was carried out by researchers from the University of California and University of British Columbia, and was funded by the National Institute of Health and National Institute of Mental Health.
The study was published in the peer-reviewed journal Psychoneuroendocrinology.
The Sun's question and answer – "How often do you need to be getting intimate to make a difference? Once a week apparently" – would seem to show the paper hasn't grasped the limitations of this research. The "once a week" bit is purely because the researchers carried out their assessment over a week. The study didn't even take into account how many times a week the person had sex.
This was a cross sectional study of mothers taking part in a cohort study. It questioned their stress levels and relationship satisfaction and looked at whether this was linked with telomere length in blood cells.
Telomeres are repetitive sequences of DNA at the tips of our chromosomes. They have no effect on the body but are essentially there to protect the important chromosomal DNA from getting damaged each time the cell replicates.
As we age telomeres get shorter, and so they are taken as a marker of cellular ageing. Studies have also shown telomeres shorten in response to stress.
The researchers say social support and positive relationships can slow the rate of telomere shortening. As good quality intimate relationships are known to be good for health, and have been linked to better physical health and longevity, this study aimed to see whether relationship quality was linked with telomere length.
The study included women participating in the Stress, Aging, and Emotions (SAGE) study, set up to investigate the stress of mothers/caregivers raising children with or without autism spectrum disorders (ASD). The women were 20 to 50 years old and recruited from the San Francisco bay area.
This study takes data collected during one week at an 18 month assessment period into the SAGE study.
Stress was assessed using the Perceived Stress Scale (PSS), designed to assess feelings of being overwhelmed, anxious or stressed over the past month.
Women were classified as high-stress maternal caregivers if they had a child with ASD and scored 13 or more on the PSS. They were classified as low-stress if they had a child without ASD and scored 19 or less on the PSS.
Relationship quality was assessed by a 14-item Dyadic Adjustment Scale. Examples of questions were "To what extent were you satisfied with/experienced tension with your partner today?" A morning diary assessed sexual intimacy by asking participants "Did you have sexual relations last night?"
Blood samples were taken and telomere length assessed in whole blood (red cells, white cells and platelets) and specific white blood cells (peripheral blood mononuclear cells).
This study included 129 heterosexual women who were in a relationship and had the relevant information available. In analysing the link between sexual intimacy and telomere length they adjusted for potential confounders; specifically age, body mass index, caregiver stress and health behaviours, such as diet and exercise.
Mothers/caregivers were on average 42 years old, 78% of white ethnicity, 55% were classified as low stress and 45% as high stress caregivers.
Measures of relationship quality, such as satisfaction with their partner, were not linked with telomere length. Meanwhile sexual intimacy was linked with longer telomere length in the whole blood cells and the mononuclear cells, specifically.
The researchers conclude: "These data provide preliminary data that sexual intimacy is associated with longer telomere length. Future studies investigating these associations are warranted."
Despite the media headlines that regular sex keeps you young, only limited implications can be drawn from this study.
This was a small sample of a specific group of women. All were mothers or caregivers, in heterosexual relationships from one region of the US. About half of them were caring for children with autism spectrum disorders and were perceived to have high stress levels as a result. Therefore they can't be assumed to represent all women.
Researchers only assessed relationship quality, intimacy and telomere length over the space of a single week. This can't prove that intimacy that week directly caused the telomere length at that point.
There are other important aspects this study couldn't account for:
Simply asking a person how satisfied or not they've been with their partner in the past week and whether they had sex the night before tells you very little. And it doesn't tell you anything about the quality of that sexual relationship.
Even if it were proved that a regular sexual relationship was linked with telomere length it is unclear whether this would actually be a relevant finding. Telomere length my help protect against cell damage, but this is not the same thing as looking and feeling young.
Nevertheless, a healthy and fulfilling sexual life can boost both physical and mental wellbeing.
Read more about how to enjoy a good sex life.