Recent research has revealed that women need at least 10 hours of sleep.

For decades, everyone has been told that they need around eight hours per night. Recent research shows that the “one-size fits all” rule is not true for women. At least ten hours Sleep is essential for optimal performance. What is the surprising reason behind this discovery? A significant part of the answer lies in the long-standing bias in medical research, which has historically focused predominantly on men — and the complex hormonal rhythms unique to women.

The Male Default In Medical Science

The sleep science problem is only one part of a larger issue: For decades, medical studies were almost exclusively conducted on male subjects. This “male-default” has shaped diagnostic criteria and drug dosages. It is often assumed that men’s physiology can be used to represent all humans. The result? It is a result of the fact that women’s physiological and hormonal differences are often overlooked. This leads to a lack of understanding about female health.

This bias in sleep research meant that conclusions on how much sleep is required were based largely on men’s sleeping patterns, which did not fully reflect women’s unique needs. In recent years, more studies have focused on women and it has become evident that women need more rest for both mental and physical recovery.

Why women need more sleep: the hormonal factor

Women’s need for more sleep is influenced by a number of factors, but hormones play an important role.

Cortisol is often called “the stress hormone” and follows a daily rhythm. It helps regulate metabolism, immunity response, alertness, and more. Healthy cortisol concentrations are highest in the early morning and decrease gradually through the day, preparing the body to sleep well. According to research, women who sleep for closer to ten-hours experience a greater reduction in cortisol over night. Shorter sleep durations, on the other hand, can interrupt this decline and lead to an elevated evening cortisol, which increases stress levels and inhibits recovery.

Also, hormonal fluctuations during pregnancy, menopause, and the menstrual period can affect sleep and cortisol levels. During menopause for example, decreased estrogen levels can lead to altered cortisol rhythms and fragmented sleep, increasing the need of longer, more restorative periods.

There are many reasons why women need more sleep.

• Brain Complexity and Multitasking

  Women’s brains often engage in more complex, multi-dimensional tasks during the day—mental and emotional multitasking that demands extra recovery time during sleep.

• More Vulnerable to Sleep Disorders

  Women are more susceptible to sleep disturbances such as insomnia, restless legs syndrome and other sleep disorders that can reduce the quality of sleep and make it necessary to sleep longer.

The health cost of underestimating women’s needs

Sleep deprivation can be a chronic problem for women who sleep “standard” 8 hours per night. This increases their risk of depression and cardiovascular disease. These risks can be exacerbated by the interplay between disrupted sleep regulation and cortisol.

This issue reflects a broader problem in medicine: many health conditions—including heart disease, autoimmune disorders, and mental illnesses—manifest differently in women, yet medical research and treatments have historically been based on male physiology, resulting in misdiagnosis and inadequate care for women.

Inclusion in Science: Moving towards a More Inclusive Science

Thankfully, these disparities are becoming more and more apparent to the scientific community. It is becoming more important to include women into clinical trials, and to break down data by gender to better understand the differences. This shift is leading to more accurate health recommendations—such as acknowledging that women generally need more sleep. This realisation, that women require up to 10 hours of sleep, is part of an overall reckoning of the gender bias in medical science. This oversight can improve sleep guidelines and also women’s overall health. By basing medical treatment and advice on research that is representative of all people, scientists can promote equity and better health for women and men.