Sleep After Exercise a Boost to the Brain

We tend to have more brain power following exercise and a good night’s sleep. But what aspect of sleep might explain the beneficial effects of physical activity on the brain? Is it sleeping longer that enhances mental prowess?

Authors of a new study think they know—and insomnia sufferers should take note.

Exercise increases sleep efficiency, in turn increasing brain powerWe tend to have more brain power following exercise and a good night’s sleep. But what aspect of sleep might explain the beneficial effects of physical activity on the brain? Is it sleeping longer that enhances mental prowess?

Authors of a new study think they know—and insomnia sufferers should take note.

Effects of Exercise on Sleep and Cognition

Research has shown that exercise—or physical activity in general—is beneficial to sleep. Physical activity helps people fall asleep quickly and sleep more deeply. It also tends to improve sleep efficiency, that is, it increases the amount of time in bed spent sleeping.

Exercise is also known to have positive effects on the brain. Physical activity enhances memory and the “executive control processes” that occur with activity in the frontal region of the brain. This part of the brain is responsible for planning, initiating, and monitoring complex mental and physical tasks.

Researchers at the University of Pittsburgh and the Georgia Institute of Technology were interested in these relationships. They wanted to know which aspect of sleep following exercise was associated with improved executive control, and whether there were differences between younger and older adults.

Study Particulars

A total of 112 community residents participated in the study, 59 young adults (ages 21–30) and 53 older adults (ages 55–80). They went through two rounds of cognitive testing spaced one week apart. The cognitive testing involved several computer-based and pencil-and-paper tasks assessing working memory, task switching, verbal ability and fluency, and delayed recall of information.

Participants also wore an accelerometer armband during the week between the two testing sessions. Similar to sleep and activity trackers on the market today, the accelerometer monitored participants’ physical activity and their sleep.

Sleep Efficiency Rules

As expected, the more physically active participants performed better on the tests. The novel finding was this: what mediated, or facilitated, this relationship was not that the exercisers slept longer than their sedentary counterparts. It was that their sleep was more efficient. This was true for both younger and older study participants.

A Relationship Between Sleep Efficiency and Insomnia

So sleep efficiency seems to be an important aspect of sleep. If you’ve got chronic insomnia—if you experience trouble thinking and concentrating after nights of broken sleep—you’ll want to take note. Insomniacs’ sleep is often inefficient. Your sleep efficiency is low if you

  • lie in bed awake for a long time before falling asleep,
  • wake up several times during the night, or
  • wake up in the middle of the night and take a long time to fall back to sleep.

Sounds familiar, right? In all these situations, you’re spending lots of time in bed lying awake rather than asleep. Your sleep efficiency is high if

  • you fall asleep quickly, and
  • your sleep is deep enough to remain solid and unbroken throughout the night.

When your sleep is efficient, you’re asleep most of the time you’re lying in bed and awake very little. This may not reflect your situation now, but it is something to work toward.

As the study above suggests, one way to improve your sleep efficiency is to get daily exercise. The authors’ “novel finding fits in line with the broad view that uninterrupted sleep may promote brain health and that this process may be facilitated through physical activity.”

There are also insomnia treatments that increase sleep efficiency. One was in the news recently, and I’ll write about it in next week’s blog post.

Does regular exercise have any effect on your sleep? If so, what is it?

The Stuff Insomniac Dreams Are Made Of

Back when my insomnia was chronic, I had a lot of scary dreams. They left me with a pounding heart and fear that could keep me awake for a couple of hours.

Surprisingly little is known about the dreams of people with insomnia. So when a new article about insomnia sufferers’ dreams came out in Sleep Medicine, I snapped it up.

Insomniac dreams can be scaryI remember dreams much less now than when my insomnia was chronic. Then, just as I felt myself about to slide over the brink of consciousness, I sometimes got a horrifying send-off: a plane exploded in a fireball overhead! I was on the road and a Mack truck was coming at me full on! I was on a roller coaster that ran off the track and was plunging to the ground! Scary dreams left me with a pounding heart and fear that could keep me awake for a couple of hours.

Surprisingly little is known about the dreams of people with insomnia. So when a new article about insomnia sufferers’ dreams came out in Sleep Medicine, I snapped it up.

Negativity in Dreams

Among humans overall, a majority of dreams with emotional content are disturbing. One hypothesis about dream content holds that dreams are mainly reflections of experiences we’ve had during our waking hours, and research suggests that one function of dreaming is to replay disturbing events in order to attenuate their emotional charge. The event gets filed away in long-term memory but some of the negative emotion accompanying the experience is lost. The result is that the person dreaming wakes up feeling less bad about it as time goes on.

Results of a few previous studies done on dreams and insomnia are mixed but, overall, they suggest that the dreams of insomniacs may be more unpleasant than the dreams of good sleepers. Insomniacs have reported more nightmares and more negative elements in sleep-onset dreams. They tend to characterize themselves more negatively in their dreams (as in feeling low self-esteem or lacking in something).

This might be because insomniacs are prone to worry and rumination at night. Worries like these—“Taxes are due in 3 days!” “I’ll never get back to sleep!” “Tomorrow I’m going to feel wasted!”—may spill over into sleep. And because insomniacs are more inclined to awakenings during the night (and to arousal overall), dream content might move more easily from short- to long-term memory, enhancing dream recall.

REM Dream Activity of Insomnia Sufferers

The new study was small (12 insomniacs and 12 matched good sleepers) but well designed. On 5 nights, participants underwent polysomnogram tests to record their brain waves and assess their sleep. On 2 of those nights, during several REM sleep episodes (when dreams were more likely to occur) they were awakened by an 80-decibel tone. Then they had to narrate their dream over an intercom, recall all memorable elements of the dream, and describe the mood associated with it.

The investigators found that the dreams of all participants contained more negative elements than positive elements, which confirms findings in past research. But when they examined the two groups separately, here’s what they found:

  • Only the insomniacs’ dreams contained significantly more negative elements (aggression, misfortunes, failures, and negative emotions) than positive elements (friendliness, good fortune, success, and positive emotions). Subjectively, too, the insomniacs appraised their dreams as being more negative than good sleepers did.
  • Good sleepers reported significantly more joy and happiness in their dreams, and a higher degree of vividness.
  • Insomniacs’ sleep was more broken than the sleep of the good sleepers. In other words, the sleep of insomniacs was less efficient. And the lower the sleep efficiency, the higher the number of negative elements in insomniacs’ dreams.

The one prediction these researchers made that didn’t hold up concerns dream and nightmare recall, which they expected would be higher among insomnia sufferers than good sleepers. In contrast to the results of previous studies, participants’ responses on a questionnaire showed that dream and nightmare recall was similar between the 2 groups.

As in Waking Life, So in Sleep

The waking hours of people with chronic insomnia are skewed toward the negative, with moodiness, low energy, and mental dross our daily fare. So it’s probably no surprise that the struggle and negativity carry over into our sleep by way of dreams.

If you have a recurring dream, please share it here.

Q&A: Sleep Efficiently for a Better Night’s Rest

A reader—I’ll call her Chantal—wrote in June with questions about insomnia and sleep restriction. A few weeks ago I heard from her again:

I’m now in week 6 of sleep restriction and I have to say my sleep is getting better. I mostly sleep for 5.5 hours a night. When I started it was 3.

But the last couple of nights, I’ve woken up in the middle of the night and had trouble falling back to sleep. I have no idea why I’m waking up. Do you have any tips for staying asleep?

Insomnia sufferers can improve their sleep by spending less time in bedA reader—I’ll call her Chantal—wrote in June with questions about insomnia and sleep restriction. A few weeks ago I heard from her again:

I’m now in week 6 of sleep restriction and I have to say my sleep is getting better. I mostly sleep for 5.5 hours a night. When I started it was 3.

My sleep window starts between 11 and 12 and ends at 6. I was having trouble staying awake until midnight, and by allowing myself to go to bed at 11 (or soon after that) I can fall asleep faster.

But the last couple of nights, I’ve woken up in the middle of the night and had trouble falling back to sleep. I have no idea why I’m waking up. Do you have any tips for staying asleep?

Chantal’s sleep has improved a lot with sleep restriction therapy. She’s nearly doubled her sleep time, going from 3 to 5.5 hours of sleep a night. But now her sleep is interrupted with wake-ups. If she wants to stay asleep at night, she needs to improve her sleep efficiency. Regardless of whether you’re going through sleep restriction therapy, it’s helpful to understand this concept if you want to improve your sleep.

Why Sleep Restriction?

Sleep restriction therapy is an insomnia treatment that consolidates sleep by first limiting time in bed to the actual amount of time a person is sleeping. (That chunk of time is sometimes called the sleep window.) Most insomnia sufferers experience sleep deprivation in the first week or two. But studies show that fairly soon this leads to deeper, more efficient sleep. In the process you gradually enlarge your sleep window until you’re sleeping efficiently and as much as you can.

Sleep Efficiency—What It Is and Why It Matters

Sleep efficiency refers to the percent of time you’re actually sleeping when you’re lying in bed at night. The sleep of good sleepers is highly efficient (i.e., they’re asleep 90% or 95% of the time they’re in bed). They drop off quickly and sleep soundly through the night.

If you have insomnia, your sleep is probably inefficient, interrupted by patches of wakefulness. You may only be sleeping 70% or 75% of the time you’re in bed.

Restricting time in bed will help you (1) fall asleep faster and (2) cut down on sleeplessness in the middle of the night. In other words, your sleep will become more efficient—and efficient sleep is typically sounder and more refreshing.

Calculating Sleep Efficiency

If you go through sleep restriction therapy, you’ll calculate your sleep efficiency at the end of each week. Here’s how to make the calculation:

  • Sleep Efficiency (SE) equals Total Sleep Time (TST) divided by prescribed Time in Bed (TIB) multiplied by 100.
  • The formula looks simpler using abbreviations and symbols: SE = TST ÷ TIB X 100.

Increased sleep efficiency is good in and of itself. But during sleep restriction, your sleep efficiency is also used to establish your sleep window for the following week:

  • A high sleep efficiency suggests it’s time to enlarge your sleep window.
  • A low sleep efficiency (anything less than 80%) suggests a need to tighten up your sleep window until your sleep is solid again.

Reducing Wake-Ups at Night

Chantal says she’s averaging 5.5 hours of sleep a night but that she’s now having wake-ups. The problem may lie in her variable bedtime (between 11 p.m. and midnight) and the amount of time she’s spending in bed. It’s easy to see if we do the math:

If on most nights she goes to bed at 11 p.m. and gets up at 6 a.m. (for a total of 7 hours in bed), her sleep efficiency may be low: 5.5 ÷ 7 X 100 = 78.6%. Inefficient sleep is characterized by patches of sleeplessness.

In contrast, if on most nights Chantal restricts her time in bed to 6 hours (as would occur if she delayed her bedtime until midnight and got up at 6 a.m., or set her sleep window from 11:30 p.m. to 5:30 a.m.), her sleep efficiency will probably be high: 5.5 ÷ 6 X 100 = 91.7%. She can increase her time in bed by 15 or 20 minutes the following week.

Tightening up her sleep window now may enable Chantal to maintain consolidated sleep as she gradually increases her time in bed.

Bottom Line

If you’re going through sleep restriction, don’t make the mistake of enlarging your sleep window too fast too soon. At the end of each week, calculate your sleep efficiency and adjust your time in bed accordingly. Slow and steady wins this race.

For those who simply want to cut down on middle-of-the-night wake-ups, try spending less time in bed.

 

Sleep Restriction: What You Need to Succeed

My video and blog on Sleep Restriction Therapy get lots of comments, and certain questions about SRT come up again and again. Here I’ll review the concepts behind this treatment for insomnia and offer pointers on how to succeed.

Sleep restriction guidelines should be carefully followed for sounder slumberMy video and blog on Sleep Restriction Therapy get lots of comments, and certain questions about SRT come up again and again. Here I’ll review the concepts behind this treatment for insomnia and offer pointers on how to succeed.

Why Restrict Sleep?

If you struggle with insomnia, chances are your sleep is not very efficient. You may toss and turn a long time before actually falling asleep, or awaken several times at night. You may wake up at 3 a.m. and not be able to get back to sleep.

Researchers have found that restricting sleep—or, more accurately, restricting time in bed—leads to increases in sleep efficiency, quality, and even length. Efficient sleep tends to be deeper and more satisfying. You wake up feeling more refreshed in the morning.

Right now you may not be sleeping very well. But if you build up sufficient sleep drive, the urge to sleep becomes so powerful that you can’t resist. The goal of sleep restriction is to enable a daily build-up of sleep drive that puts you to sleep more quickly and keeps you asleep longer—night after night.

Here’s How to Get Results

Have realistic expectations. Sleep restriction is not an overnight fix for insomnia. In fact your sleep may get worse before it gets better, and you may feel logy in the daytime, especially during the first week of therapy. (Don’t worry: this may actually speed the process up.) It’s realistic to expect to see signs that your sleep is improving within a few weeks.

Begin by keeping a sleep diary. Diving into sleep restriction without first gathering information about the length and timing of your sleep is a mistake. Sleep ability varies from person to person, and you can’t know how much to restrict your time in bed without first getting a clear picture of how much you’re actually sleeping. Download this sleep diary from the American Academy of Sleep Medicine, and make copies so you can maintain the diary throughout therapy.

Keep the diary for a week before starting treatment. Write down when you go to bed and get up in the morning, and how much of that time you’re actually sleeping. At the end of the week, calculate the average amount of time you sleep each night (disregarding for the moment how much time you spend in bed).

Make a list of quiet activities you can do at night once therapy begins. Passive activities like watching TV are not as helpful in the early stages as activities with a bit of movement—folding clothes, sorting through old photos, rearranging bookshelves. For more ideas, click here.

Establish your initial sleep schedule and stick with it. If you find you sleep an average of 5 ½ hours a night, in Week 1 restrict your time in bed to 5 ½ hours. Decide on a wake-up time and set your alarm for that time every day. Then count backwards 5 ½ hours to set your bedtime. Your sleep schedule could be from 12:30 a.m. to 6 a.m., or it could be from 10:30 p.m. to 4 a.m. Whichever one you choose, stick with it, staying up until your chosen bedtime and getting out of bed when the alarm rings. If you drift off early or if you oversleep your alarm, this will lessen the accumulation of sleep drive and retard your progress.

Avoid looking at the clock at night. Clock-watching tends to arouse anxiety in people with insomnia. Once your bedtime arrives, turn all clocks to the wall. If you can’t sleep, go to another room and do something quiet until you feel sleepy. But don’t look at the clock! In the morning when you’re filling out your sleep diary, estimate the time you were awake.

Calculate your sleep efficiency at the end of the week and set your sleep schedule for the following week. (See this blog for how make the calculation and reset the sleep schedule.) Continue the process for as many weeks as it takes to establish a solid sleep pattern and maintain a sleep efficiency of at least 85%.

Once you’ve found your ideal sleep schedule, observe that schedule night after night. Most important is getting up at the same time every morning (and resisting the urge to nap). This will prime you for sleep when bedtime rolls around and stabilize the sleep you get.

For more detailed guidance with sleep restriction therapy, see chapter 8 of THE SAVVY INSOMNIAC.

Sleep Restriction in a Nutshell

In last week’s blog I explained the rationale behind sleep restriction as a treatment for insomnia. (Here’s a link to that blog post.) Now I’ll offer a quick and dirty description of how it works.

sleep-restrictionIn last week’s blog I explained the rationale behind sleep restriction as a treatment for insomnia. (Here’s a link to that blog post.) Today I’ll offer a quick and dirty description of how it works.

The first order of business is to keep a sleep diary, recording every morning how many hours you slept the night before. After one week, calculate the average number of hours you’re sleeping. This becomes the number of hours you’re allowed to be in bed during the first week of sleep restriction. (Many sleep therapists suggest starting with no fewer than 5 hours in bed.)

Start Restricting Your Time in Bed

Decide on a wake-up time, and count backward to determine your bedtime. Stay up until then every night, doing whatever it takes to stay awake. Get up at the same time every morning.

At the end of the first week of sleep restriction, calculate your “sleep efficiency” (percent of time in bed actually spent sleeping). Divide the total number of hours you slept during the week by the total number of hours you were in bed, and multiply by 100. If your sleep efficiency is above 85 percent (some therapists recommend that your sleep efficiency be at least 90 percent), then add 15 minutes to your time in bed during the second week.

For example, if during the first week you restrict yourself to 5 ½ hours in bed and your sleep efficiency is 90 percent, during the second week of sleep restriction, you increase your time in bed to 5 ¾ hours. If at the end of the second week your sleep efficiency is still above 85 percent, add 15 more minutes for a total of 6 hours in bed. And so on from week to week, until you find the maximum time you can spend in bed without your sleep efficiency falling below 85 (or 90) percent. This is your ideal sleep time, and, once you’ve found it, you stick with it.

The Hard Part

It’s not easy complying with such a rigid schedule, especially during the first week. I found it increasingly hard to keep myself awake until midnight, the bedtime I’d set. Passive activities like reading and watching movies led to nodding off early. So I switched to activities like folding clothes, rearranging cupboards, and walking around the house.

Also, it was harder and harder to pull myself out of bed when the alarm rang at 5 a.m. For three days I walked around like a zombie, forgetting appointments and misplacing glasses and keys.

But by the end of the first week, I was falling asleep the minute my head hit the pillow and sleeping right through the night—a major coup for me.

Sleep restriction is just one among a handful of treatments you may undergo as part of cognitive-behavioral therapy (CBT) for insomnia. Three online programs offering CBT are CBT for Insomnia, Sleepio, and SHUTi. Check into one of these if you’re leery of trying sleep restriction on your own.

Does sleep restriction sound like something you would try? Why or why not?