Finding the ideal sleep duration for Mental Health and Performance

Todays insights is drawn from the Scientific article:
Sleep duration and health in adults: an overview of systematic reviews

What we will cover today:

• Takeaways:

• Let’s learn some more about this study:

• What they did:

• What the authors found out:

• What can we learn from this study?

• Quick Answers to Your Top of Mind Questions 🙋‍♂️

*Answers are based on the content of todays article.

Takeaways:

👉 Aim for 7-8 hours of sleep for optimal health:
Both sleeping too little and sleeping too much can increase the risk of health problems like heart disease, type 2 diabetes, and cognitive decline. Consistently getting 7-8 hours of sleep per night is linked to the best overall health outcomes, including mental well-being.

👉 Sleep habits influence long-term mental health:
Better sleep, particularly in the 7-8 hour range, has been shown to lower the risk of cognitive decline and improve brain health. For those concerned about mental health and cognitive function, adopting healthy sleep habits is an effective long-term strategy.

Let’s learn some more about this study:

_{Disclaimer: This summary is based on the article “Sleep duration and health in adults: an overview of systematic reviews” by Jean-Philippe Chaput, Caroline Dutil, Ryan Featherstone, Robert Ross, Lora Giangregorio, Travis J. Saunders, Ian Janssen, Veronica J. Poitras, Michelle E. Kho, Amanda Ross-White & Julie Carrier and aims to provide key takeaways and a condensed overview of its content. While the essence is drawn from the original article, some parts have been simplified or rephrased to enhance understanding. Please note that we at, OptiMindInsights or any other potential writers or contributors to our summaries, do not accept responsibility for any consequences arising from the use of this summary. The information provided should not be considered a substitute for personal research or professional advice. Readers are encouraged to consult the original article for detailed insights and references. The summary does not include references, but they can typically be found within the original publication. Always exercise due diligence and consider your unique circumstances before applying any information in your personal or professional life. We refer to the creative commons for reproducibility rights.}

This study is a review of systematic reviews aimed to explore the relationship between sleep duration and health outcomes in adults. The researchers in charge reviewed systematic studies from the last decade, and identified 11 key reviews from a pool of 36 eligible articles. These reviews included over 4.4 million participants from 30 countries, most of whom were adults aged 18 years or older. The studies primarily used subjective sleep duration assessments, with the optimal duration for health determined to be 7–8 hours per day. Across different health outcomes, no significant modification of sleep duration effects was observed by age.

Sleep is crucial for mental, emotional, and physical well-being. Not getting enough sleep is linked to higher risks of death, chronic diseases, lower productivity, and a higher chance of accidents. Public health guidelines recommend 7–9 hours of sleep for adults under 65 and 7–8 hours for older adults. Given the strong evidence connecting sleep and health, this review summarizes key findings to help improve health recommendations and guide future research.

What they did:

This study followed some officially accepted guidelines for systematic reviews and was registered in the PROSPERO database. Researchers used the PICOS framework for designing the study, which defines the Population, Intervention, Comparisons, Outcomes, and Study Design. 

The focus was on adults aged 18 and older living self-sufficient in the community, including both healthy adults and those with conditions like obesity or metabolic syndrome.

The intervention studied was sleep duration, which could be measured objectively (using tools like polysomnography or actigraphy) or through self-reports.

Eight critical health outcomes were examined:

- Mortality
- Cardiovascular disease
- Type 2 diabetes
- Mental health
- Brain health
- Falls
- Accidents/injuries.

Researchers selected reviews from published studies that met specific quality standards. Only systematic reviews that included thorough searches of at least two databases and avoided major flaws were included.

What the authors found out:

Mortality:

Three reviews found that both too little and too much sleep can increase the risk of death. Based on these studies, for each hour of sleep less than 7 hours, the risk of dying increases by 6%. So, if someone sleeps 6 hours regularly, their risk is 6% higher than someone who sleeps 7 hours. Similarly, for each hour over 8 hours, the risk increases by 13%. This shows that both short and long sleep durations are linked to higher risks of death, with 7 to 8 hours being the healthiest range.

Cardiovascular Disease:

One review found that sleeping less than 7 hours increased the risk of heart disease by 11%. Similarly, short sleep increased the risk of type 2 diabetes by 9%.

Mental Health and Brain Health:

Short sleep was not significantly linked to depression, and long sleep wasn’t either. However, one review found that 7 to 8 hours of sleep was best for reducing the risk of cognitive disorders, such as memory loss or other brain function problems.

Falls and Injuries:

Short sleep was associated with a higher risk of falls, and both short and long sleep increased the risk of injuries at work. For example, workers who slept less than 7 hours had a higher chance of getting hurt on the job compared to those who slept more.

Obesity and Bone Health:

One review found that short sleep (less than 6 hours) was linked to a 38% higher risk of obesity, while long sleep (more than 9 hours) was linked to an 8% higher risk. Another study showed that long sleep was linked to a higher risk of osteoporosis in older women.

What can we learn from this study?

The findings of this overview highlight a clear "U-shaped" relationship between sleep duration and various health outcomes. Both short and long sleep durations are linked to negative health effects, with the optimal sleep range being 7–8 hours per day. This pattern applies to several key outcomes, including mortality, cardiovascular disease, and brain health.

When it comes to mental health, the evidence was mixed. Short or long sleep durations weren’t significantly linked to an increased risk of depression. However, getting 7 to 8 hours of sleep was shown to lower the risk of cognitive decline and disorders like Alzheimer’s disease. This suggests that based on this review of review articles, while sleep duration may not directly impact mood disorders, it plays an important role in maintaining brain health and preventing cognitive issues.

A key issue identified in the studies was the reliance on self-reported sleep, which can sometimes overestimate actual sleep duration. Using more objective tools, such as wearable devices that track sleep, could improve future research on how sleep impacts mental health and other outcomes.

In conclusion, this review suggests that aiming for 7–8 hours of sleep per day is generally best for overall health, including mental well-being. It also highlights the need for more research using objective sleep measures and further exploration of how sleep duration impacts mental health, especially cognitive function.

Quick Answers to Your Top of Mind Questions 🙋‍♂️

🙋‍♂️ How much sleep should I aim for to maintain good health?
The optimal range for adults is 7-8 hours of sleep per night. Both shorter and longer sleep durations are linked to increased risks of health issues, including heart disease, diabetes, and mental health problems like depression and cognitive decline.

🙋‍♂️ Can improving sleep habits reduce mental health issues?
Yes, focusing on maintaining the recommended 7-8 hours of sleep per night can help lower the risk of mental health issues, such as depression, anxiety, and cognitive decline. Regular sleep within this range is linked to better overall mental well-being.

Are you still hungry for more resources on sleep and how to optimize your own sleep?

Check out the National Sleep Foundation for great resources.

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