Focus on Fatigue

Focus on Fatigue, Issue 30: How much sleep do you need?

By April 1, 2015 No Comments

Welcome to Focus on Fatigue.

March and April in Australia bring a much welcome changing of the seasons as we move from our hot stormy summers to the cooler autumn months. Once we find ourselves snuggling warm beneath blankets at night it can be much harder to resist the urge to hit the snooze button on our alarm clocks. As the playwright, Wilson Mizner, said, “The amount of sleep required by the average person is five minutes more.”

But what if we woke up naturally every day before our alarm clock went off? What if we achieved the exact amount of sleep we needed to function at our full potential every day? How many hours of sleep would we need each night to make this happen? This is the subject of this month’s newsletter.

The FRMS Team

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InterDynamics Pty Ltd
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Views expressed in articles and links provided are those of the individual authors, and do not necessarily represent the views of InterDynamics (except where directly attributed).

Feature Article

How Much Sleep Do You Need?

One size doesn’t fit all

It would be wonderful if we could say, “Humans need X number of hours sleep in order to perform at optimum capacity.” Unfortunately, the truth is not so simple. The amount of sleep a person needs depends most obviously on their age. A child needs much more sleep than an adult. Past that, however, things get more complicated.

Short sleepers

There are some people who are able to function happily and effectively on just 3-5 hours of sleep each night. Some famous examples include Margaret Thatcher and Thomas Edison. More recently, Jay Leno and Madonna have both claimed to only need four hours of sleep a day. But, these people are the exception to the rule.

Recent research has suggested that short sleepers may be the result of a mutation in a particular gene called BHLHE41. That is, their ability to flourish with little sleep may be something they were simply born with. It is believed that less than 1% of the population has this mutation.

Everybody else

For the other 99% of us, spending a good portion of our lives sleeping is the only sustainable way to live. But how much sleep is enough?

  • 6 hours – This is the absolute minimum necessary sleep for most people. Over a few days it is likely to result in lowered work effectiveness and performance. If a person stuck to six hours a day for several weeks they may be able to adapt in terms of work performance, however they would probably still experience drowsiness during the day.
  • 7-9 hours – This is the amount of sleep recommended for adults by the Sleep Health Foundation.
  • 11 hours – It seems that sleeping for too long each night also has negative effects, including links to depression, diabetes and a higher risk of mortality.

During a six-year study in America that involved over one million participants, both men and women, the lowest mortality rate was seen in a group sleeping an average of 6.5 to 7.5 hours a night. So, if you want a magic number, of how many hours sleep the average adult needs, the best answer seems to be around seven hours.

As individuals, however, it is our responsibility to learn how many hours of sleep we need to function at our optimal level. Once we know that number, it is imperative that we find ways to achieve adequate sleep.
How do we figure out how much sleep we need as individuals?

While there are no definite answers on the best way to figure out how many hours of sleep an individual needs each night to perform at their best, some suggestions have been made that may help. Such as:

  • Go camping – Exposure to natural light can help realign your sleep with the natural rhythms of your body. Therefore, a week of going to sleep and waking up when your body wants to can help you learn how much sleep your body needs.
  • Have a holiday – Ditching your alarm for a week or two, and allowing your body to wake up naturally, can also help you to learn how many hours your body wants to sleep.
  • Go to bed earlier – Go to bed fifteen minutes earlier every few nights until you find that you are waking up before your alarm goes off. It’s best to use this method gradually because if you suddenly go to bed an hour earlier than normal, you may just find yourself staring at the ceiling for an hour.


  • Orzel-Gryglewska, J. (2010) Consequences of sleep deprivation. International Journal of Occupational Medicine and Environmental Health, 23(1), 95-114.
  • Pellegrino, R., Kavakli, I. H., Goel, N., Cardinale, C. J., Dinges, D. F., Kuna, S. T., Maislin, G., Van Dongen, H. P. A., Tufik, S., Hogenesch, J. B., Hakonarson, H., and Pack, A. I. (2014) A novel BHLHE41 variant is associated with short sleep and resistance to sleep deprivation in humans. Sleep, 37(8), 1327-1336.
  • Youngstedt, S. D. and Kripke, D. F. (2004) Long sleep and mortality: Rationale for sleep restriction. Sleep Medicine Reviews, 8(3), 159-174.

InterDynamics News

Conferences and Presentations

This section outlines recent and upcoming InterDynamics speaking engagements and/or conferences that we recommend and will be attending.

9th International Conference on Managing Fatigue, Freemantle Western Australia, 23-26 March 2015

The ‘Managing Fatigue’ conference series is now an established and respected forum for research updates and discussion in the fatigue management community. First convened in 1992 by Associate Professor Laurence Hartley the meeting was most recently held in Freemantle last month. Each conference has primarily focused on the effects of fatigue in the transportation sector and this has involved working in conjunction with organisations such as the ‘National Road Transport Commission’ (NRTC) and the ‘Australian Transport Safety Bureau’ (ATSB). Over the years the meeting focus has also evolved to encompass a wider arena including sectors such as Aviation, Maritime, Industrial, Resources and Health.

FRMS Forum Conference, Luxembourg, 6th-7th May 2015

The 2015 Conference will take place in collaboration with the Ministry of Transport, CAA and the airlines & employee groups of Luxembourg at the Double Tree Hilton in Luxembourg on 6th and 7th May 2015.

The FRMS Forum are pleased to hold their next meeting in Luxembourg following the kind invitation from  a representative of all stakeholders in that country.

The agenda for this meeting will cover:

  • Developments within the regulatory environment with specific focus on those from Europe
  • Experiences from operators who are implementing FRMS
  • Workshops to achieve a consensus on some of the issues facing regualtors, operators and employee groups that are emerging as FRMS is adopted.

The content will be developed in the following months but please reserve the dates in your diary.

On the 5th May, a short training session on the basics of FRMS will be held for those new to FRMS to have a good basic understanding of the main principles for implementing FRMS within their organisations.

For more information please visit the FRMS Forum website.

Articles and Videos

Article: Too little sleep, and too much, affect memory

Howard LeWine, Harvard Health Publications, ‘Too little sleep, and too much, affect memory’ (, March 2014.

When it comes to memory, sleep is a Goldilocks issue: both too much and too little aren’t good. Aim for “just right,” says a new report from the Harvard-based Nurses’ Health Study.

Video: How much sleep do you actually need?

AsapScience, ‘How much sleep do you actually need?’ (, July 2014

This three-minute video discusses our topic of the month, ‘How much sleep do you need?’ Please note, there are unrelated advertisements at the end of this video.
Watch the video…


The National Sleep Foundation, in America, has recently released updated recommendations for how much sleep individuals should get based on age. Their methodology was published in the journal Sleep Health in March. The abstract is below:

Hirshkowitz, M., Whiton, K., Albert, S. M., Alessi, C., Bruni, O., DonCarlos, L., Hazen, N., Herman, J., Kitz, E. S., Kheirandish-Gozel, L., Neubauer, D. N., O’Donnell, A. E., Ohayon, M., Peever, J., Rawding, R., Sachdeva, R. C., Setters, B., Vitiello, M. V., Ware, J. C., and Hillard, P. J. A. (2015) National Sleep Foundation’s sleep time duration recommendations: Methodology and results summary. Sleep Health, 1(1), 40-43.

Objective: The objective was to conduct a scientifically rigorous update to the National Sleep Foundation’s sleep duration recommendations.

Methods: The National Sleep Foundation convened an 18-member multidisciplinary expert panel, representing 12 stakeholder organizations, to evaluate scientific literature concerning sleep duration recommendations. We determined expert recommendations for sufficient sleep durations across the lifespan using the RAND/UCLA Appropriateness Method.

Results: The panel agreed that, for healthy individuals with normal sleep, the appropriate sleep duration for newborns is between 14 and 17 hours, infants between 12 and 15 hours, toddlers between 11 and 14 hours, preschoolers between 10 and 13 hours, and school-aged children between 9 and 11 hours. For teenagers, 8 to 10 hours was considered appropriate, 7 to 9 hours for young adults and adults, and 7 to 8 hours of sleep for older adults.

Conclusions: Sufficient sleep duration requirements vary across the lifespan and from person to person. The recommendations reported here represent guidelines for healthy individuals and those not suffering from a sleep disorder. Sleep durations outside the recommended range may be appropriate, but deviating far from the normal range is rare. Individuals who habitually sleep outside the normal range may be exhibiting signs or symptoms of serious health problems or, if done volitionally, may be compromising their health and well-being.

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