Subtle sexism that pervades everyday life often gets shrugged off. But research shows it can still have lasting psychological effects – including "thinning" parts of the brain.

If you've ever been catcalled late at night, you may be familiar with the stress response it can spark. Your defensive guard can go up and leave you feeling physically shaken and vulnerable.

All my female friends have had such experiences, and all of us have at one point or another walked home in the dark holding our keys in our hands. I even joined a karate club at university, in case the worst should happen, and through repeated drills learnt how to efficiently throw an opponent to the ground and hit the right pressure point to cause pain.

When unwanted sexual attention isn't immediately threatening, however, it is often shrugged off and ignored. But that doesn't mean it doesn't have a lasting psychological effect. Research now shows even everyday acts of sexism can have repercussions that stretch throughout people's bodies and lives.

The women's rights movement has had plenty of successes over the past century. In many countries, equal pay is now a legal requirement and sex discrimination is illegal. In the UK we've had three female prime ministers, and women leaders are becoming more common more broadly.

There remains concern, however, that gender equality is at a standstill in the UK and elsewhere, or even going backwards. Gender pay gap statistics remain stubborn and violence against women and girls continues to increase.

Globally the figures are alarming – almost one in three are said to have been subjected to physical or sexual violence, or both. Then there are the subtle forms of sexism that can pervade daily life, such as being patronised or belittled. Or the benevolent sexism of seemingly positive gendered compliments, which allude to the idea that women are naturally more kind or emotional, and men more rational or dominant. These assumptions are rooted in gender stereotypes that can harm women's empowerment and "reinforce women's subordinate status".

Meanwhile, in the US, information on women's health has been recently deleted and altered from a government website, according to a report published in The Lancet, by sociologist Patricia Homan from Florida State University and colleagues. "The information that was added reinforces biological sex essentialism, framing women's bodies as weak and in need of protection and framing trans people as a threat," the report's summary noted.

The content removed from the website related to maternal and reproductive health care. This included a link to the now-defunct site "reproductiverights.gov", which provided information on accessing medications, contraception, emergency care and abortion services.

We requested a comment from the US Department of Health and Human services but did not receive a reply by the time of publication.

Put together, these are all examples of what's referred to as "structural sexism", which Homan defines as systematic gender inequality in power and resources, embedded within our social institutions. "It's really about the ways that power, status and resources are imbalanced between men and women," she explains.

The effects on women's health, unsurprisingly, can be consequential and not always immediately visible. A large study analysing over 7,800 brain scans across 29 countries found that societal gender imbalances physically change women's brains. The research showed that women living in countries with higher gender inequality had thinner cortical thickness in brain regions associated with emotional control, resilience and stress-related disorders such as depression and post-traumatic stress disorder.

Nicolas Crossley, a psychiatrist at the Pontifical Catholic University of Chile, told me last year when researching my book Breadwinners,........

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