Summary: Women experience less complete rest, more numerous awakenings, and reduced therapeutic sleeping compared to males, according to a new research on mice. These differences, according to researchers, could be related to tension hormones and biological roles but more to genetic factors than lifestyle. The results challenge decades of neglected, gender-specific sleep and medical research.
The study emphasizes the value of including both sexes in analysis, especially when developing solutions for sleep-related problems. Researchers hope that this research will encourage women to reevaluate previous research and reevaluate methods of research that have excluded them.
Important Facts:
- Adult animals had more fragmented and less sleep than males, with an hour less sleep.
- Modifications in sleep patterns are most likely caused by gender differences and stress hormones.
- Underreporting female researchers ‘ challenges skewed the efficacy and safety information for drugs.
Origin: University of Colorado
According to a new dog study from CU Boulder researchers, females sleep less, wake up earlier, and get less restorative sleep.
The studies, published in the journal , Scientific Reports, shed new light on what may govern sleep disparities in men and women and could have broad implications for medical research, which for decades has focused mostly on males.
” In people, men and women exhibit different sleep patterns, generally attributed to lifestyle factors and caregiving functions”, said senior author Rachel Rowe, assistant professor of integrated anatomy.
Our findings point to the possibility that biological factors may be responsible for these rest differences more than originally thought.
Sleep studies has exploded in recent years, with hundreds of dog studies exploring how insufficient sleeping impacts risk of diseases like diabetes, obesity, Alzheimer’s and defensive disorders—and how like diseases affect sleep. In addition, rabbits have frequently been the first to be tested for innovative drugs, including those for rest, and what side effects are associated with them.
But many of those benefits may have been skewed due to a lack of female picture, the study suggests.
According to initial artist Grant Mannino, who graduated with degrees in psychology and science and was named the College of Arts and Sciences in May, “essentially, we found that the most frequently used mouse stress in medical research has sex-specific sleep behavior.”
How mice sleep
For the non-invasive study, the authors used specialized cages lined with ultrasensitive movement sensors to assess the sleep patterns of 267″ C57BL/6J” mice.
Males slept about 670 minutes total per 24-hour period, about an hour more than female mice. That extra sleep was non-Rapid Eye Movement ( NREM) sleep—the restorative sleep when the body works to repair itself.
Mice are “polyphasic sleepers,” or nocturnal, after a brief period of arousal to survey their surroundings before returning to sleep. Females, the study found, have even shorter bouts of sleep—essentially, their sleep is more fragmented.
Similar sex differences have been seen in other animals, including fruit flies, rats, zebrafish and birds. Evolutionarily, it makes sense.
It might be that because they are typically the ones taking care of the young, females are more sensitive to their surroundings and aroused when they need to be, according to Rowe.
” If we slept as hard as males sleep, we would not move forward as a species, right”?
Stress hormones like cortisol ( which promotes wakefulness ) and sex hormones likely play a role. For instance, women who are experiencing low estrogen and progesterone levels report worse sleep during this period of their menstrual cycle.
Some people believe that females have a general lack of sleep.
” For me, the question is: Do we cause too much stress for ourselves because we do n’t get enough sleep, like our spouse or partner, and believe we do, when we actually get enough sleep?” said Rowe.
The authors hope that further investigation of biological differences can be gleaned from their findings. More importantly, they hope the study prompts scientists to re-evaluate how they do research.
Progress made, but more needs to be made.
The National Institutes of Health mandated that researchers consider” sex as a biological variable” when applying for funding for animal studies in 2016. Although progress has been made, sex bias persists in research. And it can have real consequences, the authors found.
When they simulated a sleep regimen that worked best for females, they discovered that only if the sample’s gender distribution was equal for the sample size.
Bottom line: If females are underrepresented, drugs that work best for them may seem ineffective, or side effects that hit hardest may go unnoticed.
” Most things that work in animals fail when they enter clinical trials because the pipeline from the bench to the bedside is decades-long.” Is it taking so long because” sex is n’t being deemed sufficient”? said Rowe.
The authors advise researchers to consider past studies that found that females were underrepresented in research and to include both sexes equally when possible, analyze data for males and females separately, and consider whether or not they were equal.
” The most surprising finding here is n’t that male and female mice sleep differently. It’s that no one has thoroughly shown this until now”, said Rowe. ” We ought to have known this well before 2024.”
About this research on sleep and sex differences
Author: Lisa Marshall
Source: University of Colorado
Contact: Lisa Marshall – University of Colorado
Image: The image is credited to Neuroscience News
Original Research: Open access.
By Rachel Rowe and al.,” The significance of including both sexes in preclinical sleep studies and analyses.” Scientific Reports
Abstract
The significance of including both sexes in preclinical sleep studies and analyses
There has been a significant effort made in the biomedical sciences to research the connections between sex and the mechanisms underlying various disease states and behaviors, including sleep. Here, we investigated biological sex differences in sleep using male and female C57BL/6J mice ( n = 267 ).
Physiological parameters were recorded for 48-h using non-invasive piezoelectric cages to determine total sleep, non-rapid eye movement ( NREM) sleep, rapid eye movement ( REM) -like sleep, and wakefulness ( WAKE).
We compared hierarchical generalized linear mixed models with nonlinear time effects, and we found significant sex differences between the two. Female mice slept less overall, with less NREM sleep compared to males.
Additionally, females had shorter NREM sleep bout lengths and more REM-like sleep and WAKE. In addition, we conducted a simulation exercise that simulated a hypothetical treatment that, unlike male mice, altered the sleep pattern.
When sample sizes were equal, a female-specific treatment response was accurately estimated in models with appropriate sex by treatment interaction, but it was unmeasured when sample sizes were unequal and females were underrepresented.
In pre-clinical sleep studies, it may be difficult to make accurate translational recommendations if both sexes are not taken into account in experimental designs or when sex is considered during analysis.
