Sleep Studies: Gender Bias And Its Impact

Sleep studies have been conducted on both men and women, but there is evidence to suggest that sleep studies were originally performed on men only. For example, a study by the University of Southampton found significant differences in how women and men sleep, their body clocks, and how this affects their metabolism.

Historically, women have been underrepresented in clinical trials, and this is also true of sleep studies. However, there is now a growing body of research that explores the differences between men and women when it comes to sleep. For instance, studies have shown that women need more sleep than men, falling asleep faster, and spending more time in deep sleep. Women are also more likely to experience insomnia and depression, two conditions strongly associated with insomnia.

Hormones may be another reason for differing sleep needs. Women experience hormonal changes each month and over their lifetimes, which impact their circadian rhythms and create a greater need for sleep. Menstruation, pregnancy, and menopause can all cause or contribute to sleep difficulties for women.

Additionally, gender-based differences in responsibilities, such as caregiving, more often affect sleep duration in women. Women are more likely than men to wake up to take care of others in the home, a task that disrupts their sleep.

Women sleep longer and enter REM sleep earlier than men

Sleep studies have been conducted on both men and women, and the results indicate that there are differences in sleep patterns between the two sexes. On average, women tend to sleep longer than men, with research suggesting that they need around 11 minutes more sleep per night. This may be because women's brains are wired differently and they tend to multitask more, resulting in greater sleep requirements. Additionally, women generally enter REM sleep earlier than men.

REM sleep, or rapid eye movement sleep, is the fourth stage of the sleep cycle and is characterised by high levels of brain activity and vivid dreaming. It is during this stage that memories are consolidated and stored. Studies have found that women tend to enter REM sleep earlier than men, which may be due to biological differences in their sleep architecture.

One study published in the journal 'Sleep Medicine Reviews' found that women slept approximately 8 minutes longer in non-REM sleep than men. Non-REM sleep is the first three stages of sleep, progressing from light sleep to deep sleep. The study also found that women entered REM sleep earlier than men, which is consistent with other research findings.

The reason for these differences is not fully understood, but it is believed that biological and hormonal factors play a significant role. Hormones such as melatonin, which regulates sleep and wake cycles, have been found to be secreted earlier in women than in men. Additionally, core body temperature, which is linked to sleep regulation, follows a similar pattern, peaking earlier in women.

These differences in sleep patterns between men and women have important implications for understanding sleep disorders and developing tailored treatment strategies. Recognising and addressing these differences can help improve sleep quality and overall health for both men and women.

Women are more likely to have insomnia and restless leg syndrome

Sleep studies have historically focused on men, with women being excluded from studies due to the confounding variables of menstruation and pregnancy. However, recent studies have sought to address this imbalance, uncovering key differences in how women and men sleep, variations in their body clocks, and how this affects their metabolism.

Women are more likely to be diagnosed with insomnia than men, although the reasons are not entirely clear. Lower sleep quality is associated with anxiety and depressive disorders, which are twice as common in women as in men. Women also tend to experience more fluctuations in their quality of sleep, corresponding to changes throughout the menstrual cycle.

Women have a 25 to 50% higher likelihood of developing restless legs syndrome (RLS) and are up to four times as likely to develop a sleep-related eating disorder. RLS is a neurologic disorder characterised by an urge to move one's legs, induced by inactivity and occurring mostly at night. It is a partially heritable disorder more prevalent in women than in men and commonly associated with insomnia.

Pregnant women are at particular risk of RLS, and increased parity is a predisposing factor. This suggests a role for reproductive hormones, except that menopause increases the rates of occurrence, rather than decreasing them. One hypothesis is that changes in the level of hormones, rather than absolute levels, are responsible.

Both iron (which is lower in women) and estrogen (which is higher in women but fluctuates) influence dopamine and glutamate transmission, which may contribute to women's special vulnerability to RLS. A major contribution to the higher prevalence in women is likely to be the associated comorbidities such as migraine, depression, and anxiety. These disorders and their treatments are more common in women than in men.

Men are three times more likely to be diagnosed with sleep apnea

Sleep studies have shown that men are three times more likely to be diagnosed with sleep apnea than women. This disparity is due to the difference in how Obstructive Sleep Apnea (OSA) manifests in men and women. While OSA is associated with a heightened risk of heart failure in women, it is not the case for men.

OSA occurs when the upper airway becomes blocked during sleep, interfering with breathing. It is a common condition, with approximately 39 million American adults affected by it. Globally, it is estimated that 936 million adults have mild to severe OSA. The risk factors for OSA include age, gender, and weight. The likelihood of developing OSA increases between the ages of 30 and 70, with men being two to four times more likely to be affected than women. Higher weight is also linked to a higher prevalence of OSA.

The diagnosis of OSA is done through a sleep study, also known as polysomnography (PSG), which can be conducted in a sleep clinic or at home. Sensors are used to monitor heart rate, breathing, blood oxygen levels, and brain waves during sleep. The severity of OSA is determined by the apnea-hypopnea index (AHI), which measures the number of times a person's breathing is stopped or hindered during sleep.

OSA can lead to serious health complications if left untreated. It can cause heart, kidney, and metabolic health issues. Additionally, it can result in daytime sleepiness, which can make driving dangerous and impact memory recall and focus. People with severe OSA are also at an increased risk of death from any cause compared to those without sleep apnea symptoms.

While OSA is more common in men, it is important to note that women are more likely to rate their sleep quality as lower than men and report more fluctuations in their sleep quality, which correspond to changes in the menstrual cycle. Recognizing and understanding these gender differences in sleep and circadian rhythms is crucial for developing tailored approaches and treatment strategies for sleep disorders and associated mental health conditions.

Sleep studies found women sleep 8 minutes longer in non-REM sleep than men

Sleep studies have shown that women sleep more than men, spending around eight minutes longer in non-REM sleep. Non-REM sleep is when brain activity slows down, and women tend to spend more time in this stage of sleep than men. This finding has implications for understanding the differences in sleep needs between men and women, and it suggests that biological sex plays a crucial role in sleep patterns.

The study, published in Sleep Medicine Reviews, highlights the importance of considering a person's biological sex when treating sleep disorders. It was conducted by a team of all-women researchers from the University of Southampton in the UK, Stanford University, and Harvard University in the US. The researchers found that women not only spent more time in non-REM sleep but also entered REM sleep earlier than men. REM sleep is characterised by high levels of brain activity and vivid dreaming.

The difference in non-REM sleep between men and women may be due to biological factors. Women's brains are wired differently, and they tend to multitask and use more of their brain than men. Additionally, hormonal changes throughout the menstrual cycle can impact women's sleep patterns, with one-third of menstruating individuals reporting sleep troubles due to cramps, headaches, and bloating. These factors can contribute to the greater sleep need observed in women.

Furthermore, gender-based responsibilities, such as caregiving, more often affect sleep duration in women. Women are more likely to wake up to take care of others, disrupting their sleep. They are also more likely to nap during the day, which can affect nighttime sleep quality. Cultural and societal factors, such as the expectation for women to take on the "fourth shift" of managing emotional and practical needs, play a role in these sleep disruptions.

While the time spent in non-REM sleep generally declines with age for both men and women, this decline is more substantial in older men. This suggests that the difference in sleep patterns between the sexes may change over time and be influenced by ageing. Overall, the findings of this study provide valuable insights into the differences in sleep needs and patterns between men and women, highlighting the need to consider biological sex in sleep research and treatment approaches.

Women are more likely to experience chronic pain

While it is unclear whether sleep studies were only done on men, research shows that women are more likely to experience chronic pain. This may be because women's pain is often dismissed as psychological, and the medical concepts of most diseases are based on male physiology. Women are also more likely to be prescribed sedatives instead of painkillers and face longer wait times for analgesics for acute abdominal pain.

Additionally, women's pain experiences differ from men's due to factors like genetics, social status, exercise, and information processing in the brain. Hormones, puberty, reproductive status, and the menstrual cycle also affect women's pain thresholds and perception. For instance, women are more prone to musculoskeletal pain, abdominal pain, and headaches or migraines. The National Institutes of Health (NIH) reports a 3-to-1 female-to-male ratio in irritable bowel syndrome diagnoses in the US.

Furthermore, intimate partner violence, physical trauma, and feelings of depression are also linked to chronic pain in women. Women with chronic pain may suffer more and longer than men due to these gender biases and disparities in medical understanding and treatment.

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