Home All Does Sleep Really Matter?

Marie-Josée (MJ) Salvas Shaar, MAPP '07, CPT, has studied, tested, coached, and taught smart health habits for over 13 years. Combining positive psychology with fitness and nutrition, she created a coaching method that builds better sleep, food, mood, and exercise habits, as described in her book, Smarts and Stamina: The Busy Person's Guide to Optimal Health and Performance, which includes 50 practical health-building activities. Today MJ gives keynotes for corporate wellness programs and offers continuing education for wellness professionals, who can license her Smarts and Stamina Online program. Full bio. MJ's articles are here.

If changing just one of your daily habits was enough to make you more alert, efficient, energetic, productive and motivated, would you implement that change?

This month’s theme is about humor, play and fun – an appealing concept, but often far removed from our over-scheduled, chronically demanding, not-enough-hours-in-the-day lives.

If you’ve observed children’s natural behaviors, you’ve probably been reminded that humor and play are natural parts of life. Natural when well-rested, that is. When tired, children’s behavior is a completely different ballgame. Rather than being pleasant and interested, fatigued children’s ability to behave, learn and perform is dramatically diminished. They become restless, cranky, irritable and frankly, irritating too!

The negative impact of sleep debt is just as important for adults, except that we get better at concealing it. But make no mistake: concealing sleep debt doesn’t inhibit the dreaded results.

Brain Impairment

For one, according to sleep scientist William Dement, illustrious discoverer of REM sleep, “Sleep deprivation is the most common brain impairment.” University of Pennsylvania fatigue expert David Dinges reinforces: chronic sleep loss degrades nearly every aspect of human performance, including the ability to receive, process and act on information, he warns.

Drunk at Work Other researchers in Australia have found that a sleep-deprived group of participants in a study performed no better on a series of tests after 17 hours awake than drinking volunteers whose blood-alcohol levels were of 0.05. After 24 hours awake, the sleep-deprived group performed at the same level on the tests as the 0.1 blood-alcohol level group.

If you are pulling an all-nighter for the sake of important deadlines, you may want to consider taking a nap first. Stanford researchers have shown in lab experiments that the benefits of a 45-minute nap can give you as much as an extra 6 hours of productive time. Employers reading this article might want to consider providing employees with nap rooms at work – an uncommon strategy that could provide unexpectedly uplifting results.

Immune Function Challenges

Prize #2 in the category of disturbing effects of sleep deprivation goes to our immune system. According to University of Michigan sleep scientists Luca Imeri and Mark Opp, sleep debt impairs our immune function. Drs. Roizen and Oz, authors of bestselling YOU: The Owner’s Manual reinforce: in a 2-week study, getting under 7 hours of sleep each day made people three times more likely to get sick after exposure to a cold virus.

If you are sacrificing sleep in the name of productivity, being sick more often certainly won’t help you in the long run. Try the opposite strategy for a few weeks and see how you’re doing.

Crankiness Ahead

The third problem with a lack of sleep pertains to our mood. If you find yourself sweating and closing your fists in reaction to the photocopier’s paper jam, chances are you are seriously sleep deprived. We know from Barbara Fredrickson’s research that it would take 3 (or more!) positive emotions to help us back on the learning and creativity track after this negative paper jam spin.

As an added challenge, the percentage of adults who regularly shorten their night’s sleep to 6 hours or less is greater today than at any previously recorded time. According to the National Sleep Foundation, only 28% of American adults get 8 hours of sleep regularly each night. When surrounded by individuals who are equally running low on gas, three positives can be a hard-to-reach ideal.

Resilience Break-Down
Stress at the office

As crankiness rises, so does the need for resilience. When little everyday annoyances become a source of stress, our ability to cope is solicited. Indeed, a new study headed by Eric Powell at the Research Center at Clayton Sleep Institute in St. Louis shows a bidirectional relationship between chronic stress and sleep problems. Something worth sleeping on.

When Self-Regulating All Day…

Last but not least, I hypothesize that being sleepy puts our self-regulation in overdrive. We’re cranky, but showing irritability isn’t proper office etiquette, so we put on a façade, which is a constant act of self-regulation. As we know, the more self-regulation we use, the more it gets depleted.

By the time we get home, put the kids to bed and fire off the final few emails for the day, there’s no more self-regulatory power anywhere within reach. We need a break – it’s our well-deserved TV and ice cream time! (It is no surprise to find that both increased TV watching and increased overeating are both associated with sleep debt!) TV producers know how to get us hooked, so we end up going to bed too late, and the next day we’re back to more sleep debt and irritability.

Recognize the pattern? Here’s how you can break the vicious cycle.


Purchased for the purpose of this article.

Baumeister, R. F., Zell, A. L., & Tice, D. M. (2007). How emotions facilitate and impair self-regulation.
In J. J. Gross, (Ed.) Handbook of Emotion Regulation, (pp. 408-426). New York: Guilford Press.

Dement, W. (2000). The Promise of Sleep: A Pioneer in Sleep Medicine Explores the Vital Connection Between Health, Happiness, and a Good Night’s Sleep. New York: Random House. Quote above from p. 231.

Fredrickson, B. (2009). Positivity: Groundbreaking Research Reveals How to Embrace the Hidden Strength of Positive Emotions, Overcome Negativity, and Thrive. New York: Crown.

Imeri, L., Opp, M. (2009). How and why the immune system makes us sleep. Nature Reviews Neuroscience. Abstract.

Loehr, J. & Schwartz, T. (2003). The Power of Full Engagement: Managing Energy, Not Time, Is the Key to High Performance and Personal Renewal. New York: Free Press.

Roizen, M. F. & Oz, M. C. (2005). YOU: The Owner’s Manual, Updated and Expanded Edition: An Insider’s Guide to the Body that Will Make You Healthier and Younger New York: HarperCollins.

Wagner, K. (2009, June 10). Study shows a bidirectional relationship between chronic stress and sleep problems. Paper presented at the 23rd Annual Meeting of the Associated Professional Sleep Societies. Abstract retrieved June 11, 2009, from http://www.eurekalert.org/pub_releases/2009-06/aaos-ssa060209.php.

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WJ 24 June 2009 - 4:03 pm

Its much easier to be grateful, appreciative, positive, optimistic, self regulatory, emotional intelligent, resilient…………. when you get enough sleep.

For example see this reserach where sleep improves empathy http://www.innate-intelligence.com.au/blog/?p=505

PP often overlooks the basics – its challenging to have a healthy mind when you don’t have a healthy body

Marie-Josee Salvas 24 June 2009 - 6:35 pm

Agreed on both accounts!

That said, it’s also a challenge to have a healthy body when you don’t have a healthy mind!

Sheldon Cohen presented at IPPA quite convincing research studies in which participants who had positive emotional styles were less likely to catch colds after exposure to the virus. He also mentioned that positivity is correlated with more compliance with health behaviors.

This leads to the question: the chicken or the egg? Where does one start? Do we work on the emotions or on the lifestyle choices first? So far I am becoming increasingly convinced that it starts with sleep – that’s why I wrote this article. But I’d be happy to hear other people’s opinions.


WJ 24 June 2009 - 7:07 pm


I suspect it depends on why you are not getting enough sleep.

If its because you are just too busy and only get 6 hours then its the lifestyle issues that need to be tackled.

Howver if you lie in bed and ruminate and as a consequence don’t sleep then its the mental health issue that needs to be tackled.

Dan B 25 June 2009 - 9:21 am

Hi Marie-Josee

As always, good advice well-grounded in science. I love how you plan your daily tasks around knowledge of your peak and low times of the day! Sort of like a boat captain paying attention to the tides in deciding when to enter and leave port. (Can’t resist the sea metaphor!)

From the Gulf Coast, Dan B

Marie-Josee Salvas 25 June 2009 - 10:19 am

Wayne – good point. And in the case of mental health being the challenge, then we go back to mindfulness, not only at bedtime but also throughout the day, right?

Dan – thanks! I think planning our daily tasks around our circadian rhythm is a great way to increase productivity while decreasing effort at the same time. It is also typically easy to implement, yet I am surprised how few people have actually spent time planning around it. I guess here again it’s an issue of mindfulness to a certain extent.


Senia 25 June 2009 - 11:09 am


I love that you’ve gathered all this research together. I often want to tell people how important sleep is – clients, friends- and it’s so nice to have this as a resource. I’ve been needing this and didn’t know it until you put it together.

I agree with Dan about how it’s impressive that you plan tasks around optimal alertness, like a boat captain. I know one happiness researcher who says that it’s the key to her productivity – to plan with alertness times in mind.

BTW, in your second article… which of the techniques do you most like to use yourself?

Thanks, Best!

Kathryn Britton 25 June 2009 - 11:12 am

MarieJ, Your articles remind me of a great joke around William Dement – a joke with a serious theme. He told his students that the one thing all English children remembered about history was 1066 (year of the Norman conquest). He wanted his one thing to be that if you feel sleepy while driving, it is not the beginning of falling asleep, it is close to the end. So get off the road and take care of it. He’d bring this up one way or the other in every class. Then on the final exam, he asked, “What is the single most important thing for you to remember about this class?” 70% of the students wrote, “1066.”

So I use 1066 as shorthand for my friends whenever they are embarking on long trips, and we always laugh remembering the story.

If you ever run into Dr. Dement, just say “1066.”

Marie-Josee Salvas 25 June 2009 - 7:26 pm

Senia – I don’t really need to think about any of these suggestions because I do them naturally. Going to bed and getting up at regular hours is probably the one that I derive the most benefit from. My fiance says that sleep is one of the things I do best. I’m not always quite sure how to take his comment, but I look at it on the bright side!

Kathryn – yes, you’re right! I’ll tell him 1066 if ever I am fortunate enough to meet him! His point about how dangerous it is to be sleepy behind the wheel is repeated quite often in the book, and you are right to bring it about on this forum. (I should have done it in the article, but then again we had to break my article in 2 because it was already so long!)


Kendra 10 November 2009 - 1:10 am


If you have only gotten five hours of sleep for, let’s say, three consecutive nights, is there any way you can make up those hours of sleep on the fourth day? Or will sleeping longer just make you even more tired? Is it possible to get too much sleep?

Marie-Josee Salvas Shaar 10 November 2009 - 2:40 pm

Hi Kendra!

Very good question, and one that is asked quite often!

Here’s the best way I found to explain it: sleep works much like a line of credit. If you accumulate debt, you’ll need to pay it off somehow, but there’s no point in making deposits if the account is at zero.

Here’s an example. Let’s assume you need a standard 8 hours of sleep each day and that you’ve had all the sleep you need over the past few weeks (your line of credit is at zero). Now for 3 days in a row, you can only get 5 hours of sleep. According to William Dement (on whose research the above article is based), your 3 short nights will lead you to a sleep debt of 9 hours (missing 3 hours X 3 nights = 9 hours). What his research shows is that your body will try to pay back that sleep debt by making you sleep longer on the next couple nights. You will not sleep off your entire debt in one day (that would mean sleeping 9+8= 17 hours!), and your body will want to attend other needs (restroom, food, water) before you’re done paying your debt. But but most likely your debt will be paid off within a week or so. And to complete my line of credit analogy, you pay the interest on your debt not through sleeping even more, but through reduced self-regulation, worse mood, etc (as explained in my article) during the time that the debt continues.

What his research cannot answer is what happens to people who suffer severe sleep debt over a period of a few months or even years (as it often happens when parents get a newborn baby). My guess is that as a survival mechanism, the body adjusts, probably by reducing basal metabolism (how much energy is expanded in daily activities) – just like it does when someone goes on a drastic diet and doesn’t eat sufficient calories in one day. But that’s just a guess.

Now about the second half of your question – is it possible to sleep too much – Dement says it is impossible. When your body isn’t tired, it is programmed to wake up! Sleeping more won’t serve any benefit (just like making deposits in a line of credit usually doesn’t pay anything), so the brain and body go to their next needs (again, restroom, food, water or even social connections, etc).

Lastly, can sleeping more make you more tired? Answer is yes and no. When you are severely sleep deprived, your body runs on cortisol, the long-term stress hormone. Too much cortisol is damaging to the body. A good night sleep will help drop the production of cortisol, which is a very good thing. But as a result of not having that stress hormone fueling you, you can feel more tired. The problem is when people see it as a sign that they should sleep less when it actually is a sign of recovery. If it happens to you, keep sleeping more a few more nights and know that you’re on the verge of feeling more energetic than ever!

Hope that answers your questions!



Jennifer 18 November 2009 - 10:33 pm

As a college student with sometimes subpar time management skills, I have often found myself pulling late hours finishing homework. As it got later and later during these all-nighters, I found that my attention span went down along with the quality of my work. It was as if I was willing to settle for less than my best. Also, i’ve found throughout my life that not only does the amount of sleep matter, but I personally need to stay on a pretty regular sleep schedule. I try to go to bed and wake up at the same time every day (not always possible) and when I don’t, I often find myself getting a headache. Could it be sleep patterns also have an effect on health? Also, any advice on sleeping better? I often find myself having trouble falling asleep when I have alot on my mind.

Marie-Josee Salvas Shaar 18 November 2009 - 11:13 pm


Indeed, schedule matters. The more regular you can be with your sleeping hours, the more efficient you will fall asleep and wake up.

This article was the first of 2 on sleep, and you will find this strategy along with my other recommendations to help you manage your sleep better in the second part of the complete article. Just follow the link that says here’s how you can break the vicious cycle above, and you’ll see some of my best tips.

You might also be interested in the newsletter I wrote on the topic. For more info, please visit the articles section on SmartsAndStamina.com and click on the balance section under newsletter issues. (I’ll try to forward it to you personally, but in case I couldn’t get to you!)



Sarah Hanley 25 November 2009 - 5:47 pm

Hi again,
First, I would like to say that I’ve enjoyed your articles very much. They’re about everything I try to keep in mind in my own life. Second, I was wondering if there was any specific life occurances that inspired you to write on the topics that you’ve discussed in your articles?

Keep writing!

Marie-Josee Salvas Shaar 30 November 2009 - 10:53 pm

Dear Sarah,

Thanks for your feedback!

I’m not sure if there is one specific circumstance that led me to focus on health and productivity, but rather I think it is my combined experiences so far. First, I noticed how much it mattered as a student. I could easily see how good rest, food, exercise and mindset were helping me perform and be resilient, versus how their absence led to diminished energy and results. Then I held various positions as a fitness trainer, a university teacher, a bank manager and as a coach, and in all cases, I clearly see that it works! I have seen lots of people get to health/fitness/performance levels they originally didn’t believe possible, just because they weren’t managing and nourishing their energy properly. What I do is very basic in a way, yet it is easily forgotten. People believe it is mind over matter, but it really isn’t. At least not long term.

So I’m building the business case for proper health and energy management, and often due rising healthcare costs, businesses are starting to pay attention.

All the best to you!


Lucy Hone 11 January 2012 - 1:56 pm

Hello all,
I’ve just found this article via the PPND’s 5th birthday missive. I’m so glad I did as, like Senia says, it’s a great resource for evidence for my work.
I’ve just woken (barely) from a dreadful night sleep – disrupted by an aftershock from our pesky quakes at 2am – and as someone who usually sleeps well, feel like I’ve just done three rounds with Mike Tyson. I usually perform best at 7am, today will be different.
Two comments:
1. Marie J (and Jeremey and Elaine) I love having you beside me as we continually strive to grow PP’s emphasis on the somatopsychic principle.
2. A sleep tip for parents: This doesn’t concern how to get your wee ones to sleep – there are scores of books on that topic – but I want to stress to all parents the fact that they have the opportunity to shape their children’s attitude towards sleep which will serve them well in later life. Growing up my mother made it very clear to me that sleep was King, that any time I managed to catch an extra 15 minutes in the afternoon, or get an early night was a positive achievement. Her love, appreciation and respect for sleep is one legacy that I am working to pass on to my own children. Even though she’s been dead for over a decade I still think of her if I manage to slope off to bed with a book on a Saturday afternoon, feeling that I’ve achieved something, no trace of guilt in sight. I have friends who would feel guilty doing the same, and who feel a 9.30pm bed-time is a sign of lack of achievement/busyness. So, as your children age, watch your words/attitude towards sleep and give them the same gift of a positive relationship with sleep that my mum gave me.


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