As reproductive health takes center stage in the 2024 US presidential race, a recent presidential decree issued by President Joe Biden to enhance research into women’s health has made waves. The executive order, signed on March 18, is noteworthy for its objective to integrate women’s health throughout federal agencies and propel new research initiatives. The timing couldn't be more opportune.
Throughout history, medical researchers have predominantly focused on studying males, often overlooking or dismissing sex disparities and applying their findings universally to females. Nevertheless, women possess distinct physiological traits from men—most notably evident with the onset of menstruation during female puberty and the presence of two X chromosomes—resulting in frequently receiving incomplete, subpar, or even harmful medical guidance.
This enduring absence of research tailored to females, stemming from biases related to sex and gender, prompted Dr. Stacy Sims, an exercise physiologist and nutrition scientist from Mount Maunganui, New Zealand, to dedicate her career to unraveling the ideal dietary and exercise regimens for women's optimal well-being. "By working in harmony with our physiology, acknowledging the inherent differences between women and men, recognizing that women are not merely scaled-down versions of men, imagine the potential health outcomes," she remarked during a TED talk in 2019.
A prime example is cardiac arrest. Despite the knowledge since 2007 that women are nearly twice as likely as men to succumb to heart attacks and report a wider array of symptoms associated with acute coronary syndromes, a study published by the National Institutes of Health that same year still advocated against distinguishing heart attack symptoms between genders.
Even in the present day, women continue to be inadequately represented in medical literature, as revealed by a 2022 study in Women’s Health Reports. Deep-seated misogynistic attitudes persist as well. Although the US National Institutes of Health introduced a policy in 2016 mandating researchers to consider sex as a variable in biomedical research, the outcomes have been mixed.
While the number of studies encompassing women noticeably surged after the implementation of this policy, a meticulous bibliometric analysis conducted in 2019 demonstrated that the majority of over 700 medical studies failed to analyze resultant data based on sex, thus limiting their applicability.
Sims, also the author of the evidence-based book "Roar," which delves into sex-based disparities in exercise and nutrition across various life stages, recently shared her insights on this subject with CNN.
CNN: How can it possibly be that women are still so medically understudied in 2024?
Dr. Stacy Sims: I know! Isn’t it crazy? Historically, when you think about who developed science and research, women were pushed out right at the start. The men were like, “Oh, women are lesser beings than us. They have smaller brains.” Even Darwin said that women weren’t as smart because they have smaller brains. So when you think about scientific method and how it all started, who were the people in the room? It was all men. No one really questioned the lack of women being studied. They just assumed women were smaller versions of men, so whatever works for men works for women. Tradition is really hard to change.
One thing the Covid-19 pandemic did do that I appreciate is cause researchers to sit up and say, “Holy sh*t, we really need to look at sex differences.” Because Covid-19 was more severe in men, yet side effects of the vaccine were more prominent in women. Also, long Covid has hit women more severely and has affected their brain more than men. That’s why we’re seeing all of this sex-specific stuff coming out that’s really good science instead of just generalized.
CNN: What are some basic things all women should be doing when it comes to exercise?
Sims: Any movement is good, but it’s more important that women put in strength or resistance training. It’s more for brain health. If we look at resistance training and the neural pathways it creates, we’re seeing it really does help attenuate dementia and Alzheimer’s — and there is a sex difference there as well. Historically, though, women haven’t been directed into doing resistance training. But across the board, from young to old, women should be doing strength training.
CNN: Does strength training have other impacts as women approach menopause?
Sims: Yes. When our hormones start changing between 40 and 50, it has a massive impact on our body composition. We start losing muscle and putting on more body fat. But if we have that lean mass from strength training, it really helps calm down that rate of change. Strength training also helps protect our bones and helps us keep our balance and proprioception (the awareness of where our body is in space). We don’t see these kind of changes in men until they’re in their late 50s to 70s.
CNN: What about exercise differences between the sexes when it comes to cardiovascular work?
Sims: Men can pretty much get away with everything. Women already have the capability of going long and slow, so we don’t need to do that kind of exercise — our bodies are already there. What we do need to do is high-intensity work: those true high-intensity intervals of 30 seconds or one minute. This helps women raise their metabolic rate, it helps reduce visceral (deep belly) fat and, most importantly, it helps keep our gut microbiome diverse and helps improve cardiovascular health. So when we look at all the research on high-intensity versus moderate-intensity versus low-intensity workouts, we really need to push the emphasis for that high-intensity work, plus resistance training.
CNN: Do women recover from exercise the same as men?
Sims: Right after exercise, there is a blood pressure difference. Women will experience vasodilation, so all their blood will go to the periphery, whereas men will have vasoconstriction, which means all of their blood comes back to their heart and can be pumped a lot faster for a quicker recovery. So women tend to get lightheaded and feel a little dizzy after a hard session, because all of their blood is pooling out. Drinking something cold right after exercise helps bring that blood back centrally, reduces metabolites and starts the reparation process.
CNN: What about nutritional differences between the sexes?
Sims: There is a big conversation around protein intake and how the recommended daily allowance for women is really low. It’s also based on cadaver work on 70- to 80-year-old men. So while protein is important for both sexes, we need to emphasize it for women — and especially as we age, since women become more anabolically resistant to exercise and protein intake, which means their bodies don’t respond as well to exercise and protein intake to build muscle. So it takes more protein, post-exercise, and higher loads or more volume of resistance training to get muscle protein synthesis.
In general, women should have 1 to 1.1 grams of protein per pound of body weight per day. If you’re doing strength training, have 15 grams of protein before a session and 30 to 35 grams after, which helps with strength and facilitating reparation. For cardiovascular work, have 15 grams of protein with 30 grams of carbohydrates before — the carbs help bring your blood sugar up, because women’s bodies go through blood sugar quickly — but afterward is when you need protein — 30 to 35 grams, or 40 grams for perimenopausal and early post-menopausal women.
CNN: There has been a lot publicized recently about the benefits of intermittent fasting, training in Zone 2 — long and slow — and other fads. Are these equally beneficial to men and women?
Sims: Most of the trends out there are great for men, but it’s a different story for women. My voice is always, “Let’s show why what we’re seeing for the general population is not appropriate for women, but also, what is appropriate for women?” Because no one’s used to pausing and saying, “OK, I heard this. But what was the population it was studied on? If it was studied on men, it might not be great for me as a woman. Well, what is appropriate for me?” It’s too many steps.
