Women are not engaging in sports activities for fear of being "judged about how they look", the chairman of Sport England has revealed.
Research by the body found that the public's participation in sport has declined and there are 1.75 million fewer women being active men.
This comes despite the annual Active People Survey suggesting that more than 70% of women aged 14-40 women wanted to be more active.
Executive director for Sport England, Tanya Joseph recently told HuffPost UK Lifestyle: "We did lots of research and there was one single unifying theme - fear of judgement."
Reasons include anything from getting sweaty to changing in front of others or just generally being worried about not being fit enough.
While it's still the country's most popular sport, swimming has seen a particular decline in participation from females - with three times as many women as men giving up swimming last year.
A total of 181,700 women quit compared with 63,300 men, while 455,300 women had stopped swimming between 2005 and 2014, according to a report by the Telegraph.
Nick Bitel, chairman of Sport England told the newspaper: "We know that women are being put off sport by a fear of judgment, they are worried about being judged about how they look, how fit they are, and whether they are ignoring their caring responsibilities.
"Swimming is in incredible decline. And yet the research tells us there are four million people who want to swim but who don't currently swim," he added.
"Swimming hasn't moved on. Running and cycling, you've got apps, you've got experiential occasions. The market hasn't developed in any way in swimming."
The government funded body has since launched the This Girl Can campaign, which aims to encourage more women to push aside their body hang ups and get active.