The adage 'you're as old as you feel' really does ring true when it comes to sex, a new study shows.
People who feel younger than they are reported more satisfaction with their sex lives than those who feel their age.
Researchers from the University of Waterloo in Canada studied 1,170 people aged from their mid 40s to mid 70s stretching over a 10 year period.
The group, which included those of diverse sexual orientation, were quizzed about their attitudes towards sex and ageing.
They concluded that the closer they felt to their chronological age, the lower the quality of their sex life.
Lead author Steven Mock, an associate professor in Recreation and Leisure Studies at the University said: "What was clear from the data is that feeling younger had a huge impact on how people felt about the quality of their sex life and how interested they were in having sex.
"For people in mid to later life, feeling young at heart actually appears to make a difference in the bedroom."
The study was published in the Journal of Sex Research.
Masters student Amy Estill, who conducted the research, added: "It's important to consider all of the different psychosocial and biological factors that might influence a person's sexuality.
"While feeling younger didn't have an impact on how much sex people were having, it was quite clear that feeling older does impact the quality of the sex you're having."
The research drew upon data collected in the Midlife in the United States (MIDUS) study in the between 1995 and 2005.
The MIDUS study is a national longitudinal study of health and wellbeing in the United States and measures the physical and mental health of participants over a period of decades.
The researchers took into account any chronic health conditions that might affect sexual enjoyment but didn't look at whether marriage to a younger spouse helped.
Even when all this was studied, subjective age was still the significant factor on how much people enjoyed sex.
Prof Mock added: "Typically, most people tend in middle age to feel younger than they are.
'When you are young it's not unusual for people to feel their age, or even feel more mature, but as you age, typically at around 40, you reliably don't feel older than you actually are,.
'People say 'I still feel like a 25 year old or 35 year old.
'Feeling younger than your chronological age has an effect on the quality of sex and your interest in sex.'