Tonight, Bernie Sanders takes the stage for the first time since his heart attack two weeks ago. The Washington Post reports that some voters are “wondering whether Sanders has the stamina for one of the world’s most grueling jobs.” However, it’s also been noted that “compared to the relentless media reports about Hillary Clinton’s near fainting-spell in 2016, brought on by pneumonia, the coverage of Sanders’ health problems has been light.” This comparison highlights the double standard when it comes to strength for male and female candidates.

Attacking a woman’s stamina or wellness plays into the sexist trope that women are too weak or generally unfit to serve in office. Barbara Lee Family Foundation research has shown time and again that especially when women are running for executive office, voters need more convincing that women candidates are ready to be CEO of their city, state, or country. Undercutting a woman’s strength by questioning her health is a long-used tactic to bring a woman candidate’s qualifications into question.

Often, questions about the health and the age of a candidate go hand in hand. For men, age is generally spun as experience and wisdom, although there is some rejection of this dynamic in the current Democratic presidential primary. For women, being older does not help to address qualification questions, like it does with men. Instead, older women have to do more to prove they are both intellectually and physically up to the job.

Because we’ve had 45 male presidents, we have a gendered expectation what a president looks like – and we have no examples of women pushing aside health problems to serve in the Oval Office. There are plenty of examples of past presidents doing just that: Franklin Delano Roosevelt was paralyzed from polio; John F. Kennedy lived with Addison’s disease; and, during his second term in office, Ronald Reagan was successfully treated for colon cancer and skin cancer.

While it’s important that presidential candidates of either gender be prepared for the job, it’s clear that, when it comes to health and age, women have additional hoops to jump through.