Where and what is happening in your brain when you sleep?

Apr 08, Neuroscience

Sleep has profound importance in our lives, such that we spend a considerable proportion of our time engaging in it. Sleep enables the body, including the brain, to recover metabolically, but contemporary research has been moving to focus on the active rather than recuperative role that sleep has on our brain and behaviour.

Sleep is composed of several distinct stages. Two of these, slow-wave (or deep) and REM sleep, reflect very different patterns of brain activity, and have been related to different cognitive processes.

Slow-wave sleep is characterised by synchronised activity of neurons in the neo-cortex firing at a slow rate, between 0.5 and three times per second. The neo-cortex comprises the majority of the cerebral cortex in the brain which plays a role in memory, thought, language and consciousness. In contrast during REM sleep, when most of our dreaming happens, neuronal firing is rapid and synchronised at much higher frequencies, between 30 to 80 times per second.

Such patterns of brain activity during REM sleep are reminiscent of those observed during wakefulness, and for this reason REM sleep is often referred to as "paradoxical" sleep.

Cognitive functions

There is growing evidence that slow-wave sleep is related to the consolidation of memory and is involved in transferring information from the hippocampus, which encodes recent experiences, and forging long-term connections within the neo-cortex. REM sleep has been linked to processes involving abstraction and generalisation of experiences, resulting in creative discovery and improved problem solving.

Though there are substantial similarities between wakefulness and REM sleep, numerous studies have explored differences in the activity of brain regions between these states, with the cingulate cortex, hippocampus and amygdala more active during REM sleep than wakefulness. These regions are particularly interesting to cognitive neuroscientists because they are key areas involved in emotional regulation and emotional memory. 

However, which sub-regions are active within these broader cortical and limbic areas – the pathways in the brain that produce these patterns of activation – and the precise function of the activity in these regions during REM sleep is currently under-described. 

Cortical activity in rats 

A new study published in Science Advances studied the physiology and functionality of REM sleep in a group of rats and provides insight into the cortical activity and the sub-cortical pathways that result in this activity. The level of detail of this study provides a major step forward for our understanding of the effect that REM sleep has on our brain and cognitive behaviour. 

The authors studied groups of rats who were allowed to sleep, but prevented from entering REM sleep for three days. Six hours before assessment, half of the rats were allowed to sleep normally, and half continued to be deprived of REM sleep. The rats that were permitted to sleep normally then demonstrated raised levels of REM sleep within those six hours. This enabled a comparison of the effect of recent REM sleep between groups. An additional control group of rats were allowed to sleep normally throughout the study. 

Gene expression analysis involves tracking the presence of particular mRNA or proteins that can be identified as the consequences of certain genes operating. The rats who underwent substantial REM sleep before testing were found to demonstrate greater expression of several genes that are associated with syntaptic plasticity (how quickly their synapses can adapt to changes in a local environment) and which affects the efficiency of neural transmission in the hippocampus. 

In the neo-cortex, the gene expressions related to how well our synapses adapt also increased following REM sleep, but those related to neural transmission were reduced compared with the group that was prevented from REM sleep. So, the function of REM sleep appears to be due to changes in the way that neurons communicate. This is consistent with the view that REM sleep allows the brain's memory processing systems to re-balance, which enables effective responses to experiences the next day. 

Where in the brain? 

In a further study, the same group determined the precise location of where these changes actually occur in the brain. In the neo-cortex, there was a general increase in plasticity throughout several areas, including sensorimotor regions that bring together sensory and motor functions. In the hippocampus, it was generally confined to the dentate gyrus, which is thought to contribute to forming new episodic memories among other things. REM sleep was also associated with reduced neuro-transmission throughout many regions of the neo-cortex, indicating that REM sleep likely results in a general weakening of the connections between synapses, which may enable brain networks to better learn from multiple experiences rather than be affected only by single instances. 

The final studies the group conducted determined the source of the cortical changes in plasticity and neuro-transmission during REM sleep. By tracking signal transmission between different brain areas together with chemical lesioning (in which brain areas are temporarily inactivated), they identified two further areas called the claustrum and the supramammillary nucleus as having key roles during REM sleep. 

The claustrum: consolidating emotion and memory. Credit: Was a bee

These two areas have been identified as involved in integrating emotion and memory. The claustrum is a very thin layer of neurons that are found underneath the inner neo-cortex. It is known to link to and from very many regions of this part of the brain. As such, the claustrum has been implicated in integrating stimuli from several senses and is involved in linking areas involved in emotional processing and attention. 

The supramammillary nucleus, within the hippocampus, is also known to interconnect to multiple areas of the brain, several of which are associated with emotional processing. 

The implications of this work provide converging evidence that REM sleep modulates activation and synaptic processing in areas of the brain that contribute to the processing of emotion. This is also consistent with previously untested accounts that suggest REM sleep is important for encoding memories (but without their emotional content). While the role of dreaming during REM sleep is still yet to be linked to observed effects from neuro-chemicals in the brain, understanding what is happening in our brains when we dream could yet prove to be key to processing of emotion and memory.

WHAT SYDNEY LEROUX DOES TO HER NEW HUSBAND IF HE'S SNORING.

By D'Arcy Maine | Mar 16, 2015



Unless you've been living in an underground tunnel somewhere with no WiFi signal or cell service, you're aware that soccer stars Sydney Leroux and Dom Dwyer were recently married. In fact, if you follow either of them on social media, you probably already know more about their relationship than that of people you -- GASP -- actually know IRL.

And just when you thought you knew everything about their lives, Leroux documented her new husband's annoying sleep habit and maybe her attempt at killing him. So that's a new development.

After having her sleep disturbed by Dwyer's snoring, Leroux did what anyone would do and pinched his nose. It worked ... temporarily. She posted the video of her efforts on Instagram with the caption: "When you try to kill bae."

For those concerned: Dwyer is still very much alive and well. Although he might want to find a way to get his snoring in check ... before it's too late.

SDB Treatment May Reduce Hospital Admission Rates in Chronic Heart Failure Patients

Published on March 12, 2015

ResMed today announced data from two studies about sleep-disordered breathing (SDB) in chronic heart failure will be presented at the 64th Annual Scientific Sessions of the American College of Cardiology, from March 14 through 16.

“The data we are presenting are important because they point toward a connection between breathing disorders in sleep, like sleep apnea, and chronic heart failure,” says ResMed chief medical officer, Glenn Richards, MD, in a release. “We look forward to learning the results of our landmark clinical study called SERVE-HF, that examines whether addressing sleep-disordered breathing in people with chronic heart failure improves survival.”

Final data from nearly 7,000 patients in a German registry of more than 10,000 patients with stable chronic heart failure showed that SDB was present in nearly one out of two people (46%). Prevalence of SDB increased rapidly with age. Other risk factors include male gender, more severe heart failure, atrial fibrillation, and increased weight.

This data will be presented in a poster session by Olaf Oldenburg, senior cardiologist in the Department of Cardiology at the Heart and Diabetes Center North Rhine-Westphalia, Bad Oeynhausen, Germany, on March 16 from 9:45 AM to 10:30 AM. (Session 1252, Poster 212; Prevalence and Predictors of Sleep-Disordered Breathing in Patients with Stable Chronic Heart Failure: Final data of the SchlaHF Registry; Poster Hall B1)

Data from an American study suggests that treatment of SDB may reduce hospital admission rates in patients with chronic heart failure. Patients compliant with PAP therapy had significantly reduced hospital visits in the 6 months after starting therapy compared to the 6 months before therapy. A comparable group who were not compliant with PAP therapy had no change in frequency of hospital visits.

This data will be presented in a poster session by Dr Sunil Sharma, associate professor in the Department of Medicine at Thomas Jefferson University on March 14 from 3:45 PM to 4:30 PM. (Session 1145, Poster 192; Treatment of Sleep Disordered Breathing in Patients Admitted for Decompensated Heart Failure Reduces 6 Months Hospital Visits, Poster Hall B1)

New sleep apnea policy to take effect

January 23, 2015

By Elizabeth A Tennyson

A new FAA policy on obstructive sleep apnea that addresses many of the concerns raised by AOPA is scheduled to take effect March 2.

The new policy closely follows draft guidelines released in April  2014 and will not disqualify pilots from receiving a medical certificate based solely on body mass index (BMI). Pilots believed to be at significant risk for the condition will receive a regular medical certificate and be required to undergo a follow-up assessment. Those who are diagnosed with the condition must receive treatment to continue flying.

The issue of sleep apnea came to the forefront in 2013 when the federal air surgeon described a planned policy change in an FAA medical bulletin. Under the original FAA proposal, pilots with a BMI of 40 or greater would have been required to undergo testing for sleep apnea by a board certified sleep specialist. The FAA said it planned to expand the policy to include all pilots with a BMI of 30 or greater.

But AOPA strongly objected to requiring thousands of pilots to go through expensive and intrusive testing based exclusively on BMI. The association and other aviation groups turned to Congress for assistance, and the House passed a bill that would have required the FAA to go through the rulemaking process before introducing any new policy on sleep disorders.

In December 2013, the FAA stepped back from its initial policy announcement and began working with stakeholders, including AOPA, to address concerns about sleep apnea.

Under the new policy, announced Jan. 23, the risk of obstructive sleep apnea will be determined through an integrated assessment of the pilot’s medical history and symptoms as well as physical and clinical findings. Aviation medical examiners will be provided with guidance from the American Academy of Sleep Medicine to assist them in determining each pilot’s risk.

Pilots who are determined to be at significant risk will receive a regular medical certificate and undergo a sleep apnea evaluation. That evaluation can be performed by any physician, including the AME, and does not require a sleep study unless the physician believes one is needed. Pilots will have 90 days to complete the evaluation and forward the results to the FAA’s Aerospace Medical Certification Division (AMCD), the regional flight surgeon’s office, or the AME. Thirty-day extensions will be available to pilots who need more time to complete the process.

If the evaluation does not lead to a diagnosis of obstructive sleep apnea, no further action will be required. Pilots who are diagnosed with the condition can send documentation of effective treatment to the AMCD or regional flight surgeon to arrange for a special issuance medical certificate to replace the regular medical certificate issued previously.

“The effectiveness of the new policy will depend on how aviation medical examiners implement it,” said Rob Hackman, AOPA vice president of regulatory affairs. “We continue to be engaged in this issue and we encourage AOPA members to tell us about their experiences once the policy takes effect.”

Notes from Dr. Norman Blumenstock
Athletes, Take Note: Sleeping More Can Give You a Competitive Edge

Visit the Fitness Video Library

By Dr. Mercola

Athletes, take note: if you want to optimize your athletic performance, be sure to get your zzz’s. As noted by The Atlantic:1

“Without proper sleep, whether it’s a short-term or long-term deficit, there are substantial effects on mood, mental and cognitive skills, and motor abilities. When it comes to recovery from hard physical efforts, there’s simply no better treatment than sleep, and a lot of it.”

Not surprisingly, sleep deprivation has a detrimental effect on sports performance across the board, but certain types of athletes see a particularly marked drop in performance if they skimp on sleep.

The largest performance drop-offs can be seen among endurance athletes, and sports requiring quick reaction times and reflexes.

Non-athletes will also optimize their health and longevity by paying attention to the quality of their sleep. In fact, getting enough sleep appears to be key for aging well, and maintaining healthy brain and body into old age.

Competitive Athletes Get a Leg Up with More Sleep

To determine whether an athlete might gain a competitive edge simply by sleeping more, Stanford researcher Cheri D. Mah reached out to The Cardinal’s men’s basketball team.

For two weeks, the players’ athletic performance was assessed after getting their normal amount of sleep. They were fitted with motion-sensing wristbands to determine the actual length of their sleep, which averaged in at a mere 6.5 hours per night.

Next, the players were asked to extend their sleep time as much as possible for five to seven weeks. The players increased their average sleep time by about two hours—to 8.5 hours nightly. As reported in the featured article:

“The results were startling. By the end of the extra-sleep period, players had improved their free throw shooting by 11.4 percent and their three-point shooting by 13.7 percent. There was an improvement of 0.7 seconds on the 282-foot sprint drill—every single player on the team was quicker than before the study had started.

A 13-percent performance enhancement is the sort of gain that one associates with drugs or years of training—not simply making sure to get tons of sleep. Mah’s research strongly suggests that most athletes would perform much better with more sleep...”

Unfortunately, extensive and hectic travel schedules usually make sleep hard to come by when you’re a competitive athlete. While not an ideal alternative to getting a solid night’s sleep, taking naps whenever possible can help.

For the majority of you though, who are not professional athletes, research like this shows just how important it is to get enough sleep. If athletes can improve their professional performance by sleeping more, the same will apply to “regular folks” as well.

The Importance of Staying in Sync with Nature

Maintaining a natural rhythm of exposure to sunlight during the day and darkness at night is one crucial foundational component of sleeping well. This was addressed in a previous interview with Dan Pardi, a researcher who works with the Behavioral Sciences Department at Stanford University and the Departments of Neurology and Endocrinology at Leiden University in the Netherlands.

Exposure to bright daylight synchronizes your master clock—a group of cells in your brain called the suprachiasmatic nuclei (SCN). These nuclei synchronize to the light-dark cycle of your environment when light enters your eye. You also have other biological clocks throughout your body, and those clocks subsequently synchronize to your master clock.

One reason why so many people get so little sleep, and/or such poor sleep, can be traced back to a master clock disruption. One lifestyle factor that can significantly hamper your sleep is spending the entire day indoors in an area with few or no windows.

That, combined with spending your evenings in too-bright artificial light, is a surefire way to get out of sync with the natural rhythm of daylight and nighttime darkness. The end result is difficulty falling or staying asleep when it’s time for bed, and persistent daytime sleepiness.

Improve Your Sleep Hygiene with a Fitness Tracker

Getting enough sleep is really crucial to overall good health; I strongly recommend taking the matter seriously. While overuse of light-emitting technology is part of the problem, some gadgets can actually help you improve your sleep hygiene.

We’re about to see an explosion of fitness trackers hitting the market, and I believe this can be a really good thing, provided you make good use of it.

There are already a few good ones available, but even better versions are sure to follow. The Apple Watch being launched next year is one example. Currently, one of the best is Jawbone’s Up32—it’s definitely among the most advanced fitness tracker to date.

This lightweight wristband keeps track of a wide variety of data, including exercise, hydration levels, and REM sleep. The data collected can even tell you what activities led to your best sleep, and what factors resulted in poor sleep.

With this kind of data at hand, you can start making some really healthy choices. The Smart Coach will also remind you when it’s time to hit the sack. Besides tracking your sleep patterns, a fitness tracker can also inspire you to get enough movement into your day-to-day life.

A Fitness Tracker Can Help You Lead a More Active Lifestyle

Overwhelming evidence shows that prolonged sitting is an independent risk factor for chronic health problems and a shorter lifespan, so regularly getting off your chair is just as important as having a regular workout schedule.

While some experts in this field recommend standing up at least 10 minutes out of every hour of sitting, I believe this may not be enough for optimal health. Personally, I now try to sit as little as possible. I strive to sit less than one hour per day, which is an achievable goal unless I’m travelling and am forced to sit in a plane or car.

Simply standing up has had the remarkable effect of “curing” my chronic back pain, which I’ve struggled with for many years. It would normally start after I’d walk or stand for more than 30 minutes, but since I reduced my sitting, the pain has essentially disappeared. 

Prior to this simple intervention, I’d tried four different chiropractors, posture exercises, Foundation Training, ab work, inversion tables, standing up every 15 minutes to stretch, and strength training. Yet the improvements were minimal. I’m still surprised I missed this important health principle for so long! Another recent epiphany I had is that most of us need to walk much more than we do. This is where a fitness tracker can be very helpful, as it allows you to objectively record how much you walk.

Most of us need about 7,000-10,000 steps a day, which is about four to five miles (6-9 km). Keep in mind that this is walking is in addition to, not in place of, your normal exercise program. If you can, consider walking barefoot, as this will help you get grounded—it’s even better if you can walk on the beach by the ocean. I believe the combination of high intensity training, non-exercise activities like walking 10,000 steps a day, along with avoiding sitting whenever possible is the key to being really fit and enjoying a pain free and joyful life. If you don't have a fitness tracker that records your steps and your sleep, I would encourage you to get one.

Beware of Sleeping Pills...

While most would not knowingly put their life on the line, you may be doing just that if you take sleeping pills. They’re simply NOT a viable alternative to synchronizing your sleep rhythm to the natural cycle of light and darkness... According to the statistics3 from the Centers for Disease Control and Prevention (CDC), between 50 and 70 million Americans suffer from sleep deprivation, and nearly nine million Americans take prescription sleeping pills in pursuit of good night’s rest.

Unfortunately, the price you may end up paying for taking this “shortcut” could be higher than expected. A study4 by the Substance Abuse and Mental Health Services Administration (SAMHSA) reveals that emergency room visits involving the sleep aid zolpidem nearly doubled between 2005 and 2010, reaching 42,274 visits in the year 2009-2010. Zolpidem is the active ingredient in sleep aids sold under brand names like Ambien, Ambien CR, Edluar, and Zolpimist. Polypharmacy—the use of multiple drugs—is part of the problem. In 57 percent of these overmedication cases, there were additional drugs involved:

• In 26 percent of cases, zolpidem was combined with benzodiazepines (Valium, Xanax, Ativan, etc.)
• 25 percent involved a combination with narcotic pain relievers
• Alcohol was also used in 14 percent of these emergency room visits

Sleeping Pill Use and Driving Can Be a Dangerous Mix

Recent research also shows that prescription drugs are involved in fatal car crashes at three times the rate of marijuana, and sleeping pills are among the drugs that could turn you into a danger on the road. Studies submitted to the FDA have revealed that blood levels of zolpidem above 50 ng/mL may impair your driving to a degree that increases the risk of an accident, especially among women. As a result, FDA recommended manufacturers cut the dosage of zolpidem from 10mg to 5mg for immediate-release products (Ambien, Edluar, and Zolpimist) and from 12.5 mg to 6.25 mg for extended-release products (Ambien CR).5

A 2013 CDC report6 also estimated that up to one-third of all fatal car crashes involve a drowsy driver, and daytime drowsiness is a very common side effect of sleeping pills. Other side effects associated with zolpidem include dizziness, hallucinations, agitation, and sleep-walking. It’s also important to realize that narcotic pain relievers and anti-anxiety drugs or sedatives can cause a dangerous enhancement of sleeping pills’ sedative effects.7 Sleeping pills have also been linked to a 35 percent increased cancer risk, along with a greatly increased risk of death from any cause.

Helpful Tips to Improve Your Sleep

My advice is to skip the medication and focus your attention on lifestyle changes that will allow you to get the best sleep possible. Remember, to sleep well, you need to have properly aligned circadian rhythms, and to achieve that, you need to get daylight exposure, ideally around solar noon, for a minimum of 30-60 minutes each day. In the evening, once the sun has set, dim all artificial light sources. In particular, you want to avoid the blue light wavelength.

Research shows that exposure to bright room light before bedtime suppresses melatonin production in 99 percent of individuals, which can rob you of sleep by preventing sleepiness. For night-time lighting, use blue-blocking light bulbs, dim your lights with dimmer switches and turn off unneeded lights, and if using a computer, install blue light-blocking software like f.lux.8 Also keep in mind that digital alarm clocks with blue light displays could have a detrimental effect. The following infographic, created by BigBrandBeds.co.uk, illustrates how your electronic gadgets wreak havoc on your sleep when used before bedtime.9

How Technology Affects Sleep - An infographic by the team at Big Brand Beds

The Worst Sleep Disorder of Them All

Notes from Dr. Norman Blumenstock

Stanford Doctor Names The #1 Worst Sleep Disorder

Posted: 05/02/2014 5:14 pm EDT Updated: 07/02/2014 5:59 am EDT

As a kid I used to love watching the G.I. Joe cartoon series, and still can remember one of their catchphrases: "Knowing is half the battle!" Now, over 25 years later, it occurs to me that this quote is relevant to the field of sleep as well.

Researchers estimate that more than 80 percent of people with clinical sleep issues remain undiagnosed, and so it seems that awareness around sleep disorders could use a little boost. With that intention, let's see if we can shed some light on a few things.

Dr. William Dement is known as the father of sleep medicine, and for good reason. He started the world's first sleep clinic at Stanford University in 1970, has worked tirelessly to promote sleep health, and was among the first to draw attention to the fact that sleep is as important, if not more so, than diet and exercise when it comes to well-being. He helped discover REM sleep, defined the stages of sleep, and created the index that sleep doctors use to this day to determine the severity of sleep apnea. But perhaps his most eye-opening contribution to the advancement of sleep health is identifying the granddaddy of all sleep disorders.

Ignorance.

"Ignorance is the worst sleep disorder of them all," writes Dr. Dement in his book The Promise of Sleep. What he means is that if people are unaware of the existence of sleep disorders, it is unlikely that they will seek or receive the help they need to improve their sleep. Part of the problem is that doctors do not receive much training on sleep in medical school. In fact, based on the most recent data available, doctors receive less than 3 hours of formal education on sleep during their 4 years of medical school. Three hours. Unsurprisingly, therefore, they tend not to address the sleep of their patients in their practices - has your doctor asked about your sleep in any detail? If you ask your friends the same question, I'm willing to bet that most of them would say "no."

Which brings us back to G.I. Joe. Knowing, or awareness, is half the battle - and we as patients can take some responsibility for ourselves by knowing the basics. In that spirit, here are some things to consider:

1. Approximately 70 million Americans have a sleep disorder.
2. There are over 80 recognized sleep disorders. Apnea, insomnia, and restless legs syndrome are some of the common ones, but there are many others that can interfere with sleep quality.
3. Well over 50 percent of Type II diabetes patients have a sleep disorder, which may in turn worsen the diabetes.
4. Sleep disruption may increase the growth of cancer cells.
5. Fitness trackers, while great for raising awareness, may provide a false sense of security for those with sleep disorders as they are not built to provide diagnoses.
6. Sleep duration is important, but sleep quality is just as important. What if you get eight hours, but are snoring like a chainsaw, or tossing and turning all night?
7. Sleep problems impact workplace productivity and safety.
8. Sleep is directly related to most of your body's major systems, including the immune, metabolic, and endocrine systems.
9. Most sleep disorders are treatable.

Here's the point. Sleep "hacks," tips and tricks are all well and good. But if you are one of the 70 million Americans (or hundreds of millions of people globally) that has an actual, medically-recognizable sleep disorder, then you're probably going to want to address that with a sleep-savvy physician if you truly want to optimize your sleep.

And congratulations, by the way. Now that you've read this article, the worst sleep disorder of them all is hopefully not an issue for you!

5 Things You Can Do After Lunch to Improve Sleep Quality

Notes from Dr. Norman Blumenstock
After-lunch strategies can improve sleep quality. If you incorporate these things during the day, it will improve your sleep quality at night.

by Jamie Scott, of Whole9 South Pacific , who lives at 43 degrees south in New Zealand and wakes up to a light alarm.
Last time we looked at the importance of sleep to overall health and touched on three pre-lunch strategies to help your body prepare for the coming night’s sleep.

Today we’ll be talking about after-lunch strategies to improve sleep quality. If you incorporate these things during the day, it will improve your sleep quality at night. First, we have to acknowledge that preparing for sleep several hours prior to going to bed does not come naturally to many people, let alone preparing for bed as soon as you get up. Many people simply cannot think this way, particularly when the strategies they would need to put in place during the day to ensure a good sleep at night put them into conflict with many other aspects of their day – such as work, family, social occasions, and so on. As a general rule, most of us will think and act in the here and now for many of the key decisions in our daily life rather than for something down the track.

Life, however, is full of compromise. So while some of these strategies might be difficult to do if they conflict with other areas of your life, you may need to ask what is more important in the grand scheme of things. Poor sleep, and the negative health consequences that travel with it, are so pervasive and damaging that those sleep-improvement strategies might just be worth it. And nobody ever complained of feeling fully-rested, energised and not chronically feeling under-slept.

Our morning strategies were largely focused on waking the body up properly and using the light and the composition of your breakfast to send all the right wake-up signals to your body, setting the stage for a circadian rhythm that is properly calibrated to the natural light-dark cycle. Doing so has the effect of synchronising your body clock with light and dark cycles so that you get tired and sleepy at the right time of the day (night-time) and that you have the correct precursors there in place to help your body produce enough of the hormone which will induce sleep for you (melatonin).

Having set up these important processes in the morning, the key to the afternoon then, is not to do anything to disturb and disrupt all that good work.

1. Kill the Caffeine

One of caffeine’s effects on our body, and indeed the very reason it helps to wake us up and make us feel alert, is its ability to boost our cortisol levels. In very simple terms, cortisol has a couple of key functions;

1. It is the hormone responsible for waking us up in the morning, mobilizing energy and helping our brain fire on all cylinders.
2. It is one of our key stress hormones.

If anyone knows anything about sleep, you will know that feeling stressed, even at a low level, makes sleep difficult to come by. Caffeine consumed in the morning is generally okay as the cortisol it stimulates is only minor given the amount which is already in circulation as part of our body waking up. But as we hit the afternoon and our natural cortisol levels are starting to drop, the last thing we need to do is to spike them back up with caffeine.

Caffeine has a half-life of approximately 6 hours (though this varies significantly person-to-person), meaning that it takes this long for your body to metabolise half of the amount of caffeine you have consumed down to half the dose. So if you drink a cup of coffee containing 100mg of caffeine, it will take approximately 6 hours to get it down to 50mg in your bloodstream.

If you are constantly drinking coffee all day, particularly late in the day, you will be increasing your caffeine levels (and thus sleep-destroying cortisol) faster than you can get it out of your system. Drink too much caffeine throughout the day and there is a good chance that you will be going to bed with the equivalent of a shot of espresso still in your system.

There is also considerable variation in how efficiently caffeine is metabolised, with some people carrying a specific genetic variant being able to break down caffeine more rapidly. But don’t get all excited – the majority of people are “slow metabolisers” of caffeine, and thus these guidelines are more likely to apply to you than not.

I have had people assure me that they can still fall asleep even after having a coffee late in the day. However, there is a big difference, qualitatively, between being able to fall asleep and going through all the natural deep sleep cycles you need to throughout the night.

This qualitative distinction is also a reason that alcohol is absolutely not your friend if sleep matters to you, since any significant amount of alcohol within a couple hours of sleep negatively affects the type of sleep you get, resulting in abnormal sleep patterns throughout the night. Being asleep is not the same as being in a deep sleep – something caffeine is very good at stopping you from entering, and alcohol is good at stopping you from maintaining. Red Bull and vodka? The worst idea ever.

To minimise the effect caffeine might be having on your sleep, it is a good idea to quit all sources of caffeine about 6-8 hours out prior to bed. In practical terms, this means you might be able to get away with an early afternoon coffee, but make that your last for the day. If you have any sleep or fatigue issues, we also recommend a Caffeine Holiday a couple times a year, too.

2. Blackout the Bluelight

From the Morning Edition, you will recall that I talked about how light is a key stimulus required to wake you up in the morning (hence why it is easier to wake up in the middle of summer compared to the middle of winter). When we talk about natural light being a stimulus to wake you up, what is specifically meant is the blue light spectrum of natural light. Rather inconveniently (but not by chance), all of our new modern techno toys – computer screens, tablets, smartphones, etc., emit light in almost exactly the right wavelength to stimulate the same process.

In other words, the blue light streaming into your eyes from your smartphone that you are holding right up to your face at 9 o’clock at night as you tell the world, via your InstaTwitFace account, that tonight is going to be the night that you finally get a good sleep, is actually sending a signal to your body that the sun is up and it is time to wake up. Research shows us that blue light (even when very dim) has a significant alerting effect – similar to caffeine!

Research in this area has shown that even just a small amount of use of these gadgets at night can delay your melatonin pulse (the hormone which will put you to sleep) by up to 2 hours. So if you are leaving it until 11pm at night to settle into bed, but you have been using your gadgets all night, it could be well after 12-1am before you really fully fall asleep.

Melatonin, in the normal run of things, starts pulsing at around 7pm and really winds up about 9pm. So, ideally, you would want to avoid overdoing the blue light toys around that time. Yeah, right. If you think asking someone to give up sugar is hard, try asking them to give up their iPhone and MySpaceFace account in the evening. It generally ain’t happening for anyone under the age of 30.

Your ‘hack’, should you find it completely impossible to unplug at night, is to wear glasses with orange lenses(similar to what cyclists wear for low light riding), as these glasses filter the sleep-killing blue light.

3. Improve Your Bedroom Environment

Next on our countdown to bedtime, is a check of your sleeping environment. Specifically, we want to look at the bed, the temperature, and the light. You are going to spend at least one-third of your life in bed, so a comfortable bed and pillows are going to be a good investment. For the bed at least, this isn’t perhaps a quick fix if it isn’t the most comfortable of sleepers, but certainly put it on your long list if you just can’t get comfortable.

Of more immediate concern, however, is the temperature of your room. Humans tend to sleep best in a room a bit on the cooler side, but not too cold. Around 16 degrees C (61-62 degrees F) seems to be optimal. This may necessitate cooling the room in summer or heating the room/bed in winter. Being too hot or too cold is a potent disruptor of sleep.

Try to also kill any artificial light sources – all the LEDs from alarm clocks, flashing notification lights on phones, or light from outdoor sources such as the streetlamps. Alarm clocks should be covered or put under the bed, phones and their notification systems should be off (airplane mode works great for this, too). Use the room layout and/or blackout curtains to ensure external light sources like street lamps aren’t seeping in. It’s also a good idea to avoid watching TV or movies in bed. Ideally, your bed is for sleeping and sex, not reading or watching TV or browsing Amazon on your iPad.

If you live in an area where sound pollution is an issue, a white noise machine is a great tool to help reduce how much sound pollution impacts your sleep. There are also mobile phone apps that work well, too.

4. Create a Bedtime Routine

A bedtime routine is a great way to tell your brain that it’s time to start winding down. For those of you with children, you’ll know that a consistent bedtime and routines help with sleep – this is true for adults as well. Dimming the lights, reading a (paper) book, or drinking a cup of herbal tea are good ways to set the tone for slipping easily into Dreamland. Massage, a warm shower or bath, and sex are all great soporifics. (A soporific is the sleep equivalent of aphrodisiac, and I know you know what that means.) Apply accordingly.

Some people find that gentle exercise such as a walk or a restorative yoga class help with sleep, but I will caution you against very intense or prolonged training within a couple hours of bedtime, as the cortisol response from your 10K run near lactate threshold or your 45 minute circuit training class will likely delay the onset of deep sleep.

That being said, evening exercise is better than no exercise at all, so if you are confined to the late evening hours for training, moderating your intensity and allowing more recovery between sets/intervals may help offset the unnatural schedule of modern life.

5. Reduce Emotional Commotion

One of the most potent simulators of the stress response is interpersonal conflict. Schedule all fights with your spouse before noon, and don’t read work-related emails right before bed. Nothing like that note from your boss to get you all wound up. Action movies or psychological thrillers can really get your heart pounding and make it tough to wind down right afterward, too. Episodes of Game of Thrones are hardly a good evening entertainment choice. Even really rousing books (especially engaging works of fiction) can get your cognitive engines whirring, which may or may not be a good thing right before bed.

As you can see, there is a lot involved with getting a good night’s sleep. When someone complains of not being a good sleeper, rarely have they ticked ALL of the boxes outlined in this before lunch and after lunch sleep strategy series and given them a chance to work. There are other sleep disruptors, yes, but these are the basics which everyone should apply first.

Childhood Diet Habits Set in Infancy, Studies Suggest.

Notes from Dr. Norman Blumenstock
Obesity is a factor in developing sleep apnea. Let's start early in a attempt to prevent our kids from developing this condition.

By CATHERINE SAINT LOUISSEPT. 2, 2014

Efforts to improve what children eat should begin before they even learn to walk, a series of nutritional studies published on Tuesday has found. Taken together, the data indicate that infant feeding patterns persist far longer than has been appreciated.

“Our early taste preferences, particularly for fruits and vegetables, and on the flip side for sugary beverages, are lasting,” said Dr. Elsie M. Taveras, chief of the division of general pediatrics at MassGeneral Hospital for Children in Boston, who was not involved in the new research.

“These studies are suggesting that in terms of diet quality, the die might be cast in the first year,” she added.

The package of 11 studies was published in the journal Pediatrics and was funded by the Centers for Disease Control and Prevention and the Food and Drug Administration, among others. Investigators tracked the diets of roughly 1,500 6-year-olds, comparing their eating patterns to those observed in a study that followed them until age 1.

Previous research has shown that taste preferences are developed in infancy. Yet until now it was unclear how infant diets bear on what children prefer to consume years later, once in school.

Women breastfed their children outside City Hall in New York last month during a rally to support breastfeeding in public. Research has shown that breast-fed infants are more accepting of new foods than babies who drank the same-tasting formula day after day. Credit Eduardo Munoz/Reuters

As it turns out, “when infants had infrequent consumption of fruits and vegetables, they also had infrequent consumption at 6,” said Kelley Scanlon, an epidemiologist at the C.D.C. and the senior author of a few of the new studies.

Dr. Scanlon and her colleagues suggested that it is best to interest children in fruits and vegetables by late infancy — roughly between 10 and 12 months old.

Their analysis took into account factors that could skew results, like race, family income and breast-feeding. Other factors may play a role in establishing a child’s diet patterns, such as whether a child fears trying new foods, said Catherine A. Forestell, an associate professor of psychology at the College of William and Mary, who researches eating habits from infancy to adulthood.

Still, Dr. Scanlon’s finding emphasizes the importance of exposing infants to a variety of fruits and vegetables as they make the transition to table food.

“I do believe in the importance of the early experience,” said Dr. Forestell, adding that it is crucial for parents “not to be deterred by an initial negative response.”

In a 2007 study by Dr. Forestell, infants who were offered green beans for the first time squinted and wrinkled their noses. But these young critics willingly opened their mouths to try another spoonful if parents persisted, she said.

Another study in the new series found that babies who consumed any amount of sugar-sweetened beverages were two times more likely to drink them at least once daily at age 6. A third study found that infants ages 10 to 12 months who were given sugar-sweetened beverages more than three times a week were twice as likely to be obese at age 6 than those who consumed none as infants.

It is not clear what impact breast-feeding might have on a child’s later diet. A mother’s eating habits are reflected in the taste of her breast milk, providing a “flavor bridge” that eases her baby’s transition to the foods she ate regularly while nursing.

Breast-fed infants are more accepting of new foods than babies who drank the same-tasting formula day after day, research has shown. A C.D.C. study in the new series found that children who were breast-fed were more likely to consume water (versus sugar-sweetened beverages), fruits and vegetables at age 6.

Cria Perrine, an epidemiologist at the C.D.C., and her co-authors concluded one additional perk of breast-feeding may be an “improved child diet.”

Recent research that took into account economic and cultural variables has thrown into question whether breast-feeding protects against obesity into the preteen years, Dr. Taveras said. But a strong relationship between breast-feeding and protection against obesity up to age 3 has been documented. Dr. Perrine’s study suggests one way breast-feeding might protect against early obesity, Dr. Taveras said.

Some experts argue that parents lack consistent guidance on how to interest infants in unfamiliar, often bitter vegetables. The task is made tougher by the fact that infants do not need repeat exposures to become enamored of sweet and salty foods.

“We don’t do a very good job of teaching parents about good nutrition in infancy,” said Deanna Hoelscher, the director of a center for healthy living at the University of Texas School of Public Health in Houston.

In March, a research review published in The American Journal of Clinical Nutrition called for separate dietary guidelines for infants and toddlers. Currently, the Dietary Guidelines for Americans makes recommendations only for ages 2 and older.

It may not be obvious to parents, for example, that noncarbonated drinks with added sugar, like cranberry juice cocktail, should be avoided in the first year. Dr. Sohyun Park, a C.D.C. epidemiologist and the lead author of a study in the journal, noted that 27 percent of the infants studied had been fed sugar-sweetened beverages.

Indeed, nearly 9 percent were fed them before 6 months of age. Yet the American Academy of Pediatrics recommends only breast milk for the first six months or, alternatively, formula.

Still, all is not lost for parents who failed to feed their infants puréed green beans, Dr. Forestell said. But there is a catch. Children tend to sample, say, brussels sprouts more readily when they see adults eating them, too. “It’s not just changing your children’s diet,” Dr. Forestell said. “It’s changing the whole family’s, and that’s the kicker, isn’t it?”