Study: Caffeine before bedtime offsets your internal clock

A study shows that drinking caffeine three hours before bedtime can delay your internal clock significantly.

A double espresso three hours before bedtime can induce a 40-minute time delay in your body's internal clock, making it harder to go to sleep on time and more challenging to wake up in the morning, scientists have shown for the first time.

The study led by the University of Colorado Boulder and the Medical Research Council's Laboratory of Molecular Biology in Cambridge, shows for the first time that evening caffeine delays the internal circadian clock that tells us when to get ready for sleep and when to prepare to wake up.

The research team showed the amount of caffeine in a double espresso or its equivalent three hours before bedtime induced a 40-minute phase delay in the roughly 24-hour human biological clock.

The study also showed for the first time how caffeine affects "cellular timekeeping" in the human body, said CU-Boulder Professor Kenneth Wright, who co-led the study.

"This is the first study to show that caffeine, the mostly widely used psychoactive drug in the world, has an influence on the human circadian clock," said Wright.

"It also provides new and exciting insights into the effects of caffeine on human physiology," he said.

For the study the team recruited five human subjects, three females and two males, who went though a double-blind, placebo-controlled 49-day protocol.

The subjects were tested under four conditions: low light and a placebo pill; low light and the equivalent of a 200-milligramme caffeine pill dependent on the subject's weight; bright light and a placebo pill; and bright light and the caffeine pill.

Saliva samples of each participant were tested periodically during the study for levels of the hormone melatonin, which is produced naturally by the pineal gland when directed to do so by the brain's "master clock."

The master clock is re-set by exposure to light and coordinates cellular clocks throughout the human body.

Melatonin levels in the blood increase to signal the onset of biological nighttime during each 24-hour period and decrease at the start of biological daytime, said Wright.

Those who took the caffeine pill under low-light conditions were found to have a roughly 40-minute delay in their nightly circadian rhythm compared to those who took the placebo pill under low light conditions, said Wright.

The magnitude of delay from the caffeine dose was about half that of the delay induced in test subjects by a three-hour exposure to bright, overhead light that began at each person's normal bedtime.

The study also showed that bright light alone and bright light combined with caffeine induced circadian phase delays in the test subjects of about 85 minutes and 105 minutes respectively.

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How caffeine disrupts your sleep

New research looks into the specifics of how late-in-the-day caffeine can disrupt your sleep at night.

You hear it all the time when it comes to sleep: Don't drink caffeine too late in the day. It's among the most common sleep tips -- and it's a good one. Caffeine, with its stimulant effects, is disruptive to good sleep. And these days, with the popularity of energy drinks and other caffeine-laden beverages and snacks, it's not difficult to wind up consuming caffeine throughout the day, even if you've set your coffee cup aside. The negative health consequences of too much caffeine also extend beyond sleep problems. Research shows that caffeine may contribute to cardiovascular problems. A recent large-scale study also suggeststhat heavy caffeine consumption -- more than four 8-ounce cups of coffee per day on a daily basis -- is linked to higher mortality rates in men and women.

But how late in the day is too late in the day to be consuming caffeine? Despite consensus about caffeine's sleep-disrupting effects, recommendations about the timing of caffeine consumption -- and when it's best to stop for the day -- can vary widely. Though an abundance of research has been conducted to establish caffeine's negative effects on sleep, very little attention has been paid to the specific timing of caffeine consumption relative to bedtime.

A new study attempts to fill in some of these important specifics about the effects of late-afternoon and early-evening caffeine consumption on nightly sleep. Researchers at Michigan's Henry Ford Hospital's Sleep Disorders & Research Center and Wayne State College of Medicine analyzed the sleep-disruptive effects of caffeine consumption at different lengths of time before bedtime. They found that caffeine consumed even six hours before bedtime resulted in significantly diminished sleep quality and sleep quantity. This is believed to be the first study to investigate directly the effects of caffeine at specific times before nightly sleep.

The study included 12 adult men and women, all of whom were healthy and were normal sleepers who in their regular lives were moderate consumers of caffeine. During the study period volunteers kept up their normal sleep routines, which included bedtimes between 9 p.m. and 1 a.m. and wake times between 6 a.m. and 9 a.m. Participants' total nightly sleep duration fell somewhere in the range of 6.5 to 9 hours per night, with no regular habit of napping during the day. Throughout the study researchers tracked sleep by having participants keep sleep diaries and by using at-home sleep monitors. Participants were given doses of caffeine in pill form as well as placebo pills, on a schedule that enabled researchers to measure the sleep-disruptive effects of caffeine taken at three different points: at bedtime, three hours before bedtime, and six hours before bed. They found significant disruptions to sleep as a result of caffeine taken at all three points:

• Caffeine consumed zero, three, and six hours before bedtime significantly reduced total sleep time. Even caffeine consumed six hours before bed reduced total nightly sleep amounts by more than one hour.
• Caffeine consumed at all three points diminished sleep quality. Caffeine taken three and six hours before bedtime, as well as caffeine consumed at bedtime, significantly increased the amount of time spent awake during the night.
• Disruptions to sleep as a result of caffeine were perceived by volunteers (as recorded in sleep diaries) for caffeine consumed at bedtime and three hours before bed, but were not reported for caffeine taken six hours before bed. However, sleep monitors measuring total sleep time, and sleep efficiency (time spent sleeping relative to total time spent in bed) showed that caffeine consumed six hours before bedtime had significant detrimental effects to both.

This last finding is especially important, because it suggests that people can't -- and shouldn't -- rely entirely on their own perceptions of how much or little caffeine affects their sleep, especially caffeine consumed in the afternoon. Even if you don't feel that late-afternoon cup of coffee has a negative impact on your sleep, this study suggests that it is likely to be interfering nonetheless. This is one reason that I have long recommended a 2 p.m. cut off time for caffeine consumption.

Remember, limiting caffeine doesn't mean removing it entirely from your daily routine. A moderate amount of caffeine, consumed at the right times, can be useful and evenhealthful, stimulating alertness and energy. These new findings provide us with some really important specifics about just how significantly late-in-the-day caffeine can undermine a good night's sleep. Want to enjoy your coffee without wrecking your sleep? Follow these basic suggestions for consuming caffeine in a sleep-friendly way:

Stick to a 2 o'clock cut off. As this current study shows, late-afternoon caffeine can cause problems for your sleep, even if you aren't aware of it. To avoid sleep disruption, restrict your caffeine consumption primarily to the morning hours. If you do have a midday cup of coffee, make sure to drink it before 2 p.m.

Taper caffeine as the day progresses. Start your day with your most highly caffeinated beverage and ease up on the caffeine as the morning goes on. First thing in the morning is likely when you'll crave caffeine the most, and when it can do you the most good in terms of boosting energy and shaking off the effects of a night's sleep. Switch over to tea or decaffeinated coffee as the morning continues, to keep overall daily caffeine amounts moderate and be comfortably caffeine-free by mid-afternoon.

Avoid jumbo drinks. These days, everything seems to be "super-sized" -- and caffeinated drinks are no exception. From a 20-plus-ounce latte or soda to a caffeine-packed energy drink, a lot of caffeine products deliver way more of the stimulant than is healthful. Stick to something much closer to the old-fashioned 8-ounce cup, and savor it.

Don't ignore your sleep problems. Being tired makes us more likely to feel the need for caffeine, and that extra consumption can in turn make sleep problems worse. Avoid this sleep-disruptive cycle by making sleep a daily priority. Practice good sleep hygiene and talk to your doctor about how you are sleeping, particularly about any problems that arise.

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Coffee six hours before bedtime can reduce sleep by an hour

A study shows that coffee consumed six hours before bed can reduce sleep time by an hour or more.

A new study has revealed that caffeine consumption even six hours before bedtime can have significant, disruptive effects on sleep.

The study led by Christopher Drake, PhD, investigator at the HenryFord Sleep Disorders and Research Center, showed that about 2-3 cups of coffee taken at bedtime, three and even six hours prior to bedtime significantly disrupts sleep.

Even when caffeine was consumed six hours before going to bed, objectively measured total sleep time was dramatically reduced (more than one hour).

Drake said that drinking a big cup of coffee on the way home from work can lead to negative effects on sleep just as if someone were to consume caffeine closer to bedtime. People tend to be less likely to detect the disruptive effects of caffeine on sleep when taken in the afternoon.

Drake and his research team studied 12 healthy normal sleepers, as determined by a physical examination and clinical interview. Participants were instructed to maintain their normal sleep schedules.

They were given three pills a day for four days, taking one pill at six, three and zero hours prior to scheduled bedtime. One of the pills contained 400 mg of caffeine, and the other two were a placebo. On one of the four days, all three pills were a placebo. Sleep disturbance was measured subjectively with a standard sleep diary and objectively using an in-home sleep monitor.

The results suggest that caffeine generally should be avoided after 5 p.m. in order to allow healthy sleep.

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Sleep Tips for Teenagers and Young Adults

Many teenagers don't get enough sleep per night and this results in negative health outcomes. This article discusses how teenagers and young adults can get better sleep patterns to avoid the negative health consequences.

Getting less than four hours of sleep every night and waking up early the next day almost seems to be the norm for many Singapore teenagers. Sleep problems can dampen your mood, zap your energy and reduce your concentration in school. Some gain weight or become depressed.

"Studies have shown that people who sleep less than four hours have higher mortality rates than those with seven-eight hours of sleep," says Dr Toh Song Tar, Consultant ENT Surgeon, Department ofOtolaryngology and Sleep Disorder Unit, Singapore General Hospital (SGH).

During sleep, the body releases a growth hormone that is important for physical growth in children and teens. Teenagers should get eight to nine hours of sleep every night, adds Dr Toh. Otherwise their physical growth may be affected.

So what causes teenagers to lose sleep?

Youths generally cite the following causes for their sleep problems:

• Worrying over unfinished business (school work, tests and exams)
• Playing video games late at night
• Online chats with friends
• Difficulty falling asleep (insomnia)
• Watching late-night television
• Stress

But there is also a biological explanation for the "sleep late, wake up early" syndrome in teenagers. The onset of puberty and a teenager's penchant for late nights may cause the body to delay melatonin production, a hormone which induces sleepiness and regulates sleep patterns.

Myths about sleep

• Loss of sleep can be compensated

Sleep debt cannot be compensated and chronic sleep deprivation can lead to obesity, hypertension and heart disease.

• Drinking alcohol can make you sleep better

Drinking alcohol at night may make you feel drowsy and sleepy, making it easier for you to fall asleep. But it will reduce REM sleep or deep sleep and cause multiple awakenings at night, thus affecting your overall sleep time and sleep quality. Over time, one would also need more and more alcohol to get to sleep.

• Exercising can overcome sleep problems

Depends on what time you exercise. Late-night exercising may not help with insomnia. At night, body temperatures normally fall as you prepare to sleep, while rigorous exercise temporarily raises your body temperature and keeps you wide awake. Avoid exercising at least four hours before bedtime.

6 tips to overcome sleep problems

1. Stay away from bright lights at night

This means stop watching television and playing computer games by a certain time. Avoid brightly lit objects such as mobile phones and iPads because light sends false messages to the brain that it is still day, and causes a delay in melatonin production.

2. Keep your computer or laptop away from your bedroom or bed

This may reduce the temptation to start playing computer games, watch videos, chat with friends or surf the Internet.

3. Keep a to-do list

Make a list of things you have not done before going to bed. This will ease your mind and stop you from thinking about unfinished business. An overactive mind can cause sleep problems.

Related article: 16 tips to cope with stress

4. Develop a regular sleep pattern

Try to sleep and wake up at about the same time every day. A regular sleep pattern helps you sleep better.

5. Avoid coffee and caffeinated drinks up to 14 hours before bedtime.

Caffeine is a stimulant which can stay in your body for up to 14 hours. If you are sensitive to caffeine, don't drink coffee after breakfast or caffeinated drinks after lunch to avoid sleep problems.

6. Drink a glass of warm milk

Drinking a glass of warm milk is relaxing. An amino acid called tryptophan, found in milk and banana, may help to induce sleep.

"Make small lifestyle changes such as watching less late-night television and refraining from playing computer games late into the night. Sleeping pills are best avoided as they can create a dependency. Only take them if they're prescribed by a doctor," says Dr Toh.

If you suffer from snoring and persistent sleep problems, do see a sleep specialist to rule out any underlying medical causes such as sleep apnoea, a condition in which the person doesn't breathe normally during sleep.

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IS IT A HEADACHE OR A MIGRAINE?

This article discusses the difference between a migraine and a headache, and different ways to help ease the pain.

Pounding headache? 

The instinct is to pop a painkiller, particularly if you’re one of more than ten million people in Britain who have frequent headaches. 

Yet last week, the watchdog National  Institute for Health and Clinical Excellence (NICE) warned that taking pain-killers regularly can reduce their effectiveness and make the brain more sensitive to pain and prone to further headaches.

Those who take pills such as aspirin, paracetamol or ibuprofen for at least ten days a month over three months are said to be at particular risk of ‘medication  over-use headaches’, as they’re called.

NICE expressed concern that doctors are often not diagnosing the type of pain or offering the best treatment. 

So, what is the most effective way to treat a headache? We talked to the experts...

IS IT A HEADACHE OR A MIGRAINE?

Often a tablet isn’t what people need, says consultant neurologist Dr Nick Silver, of the NHS Walton Centre for Neuroscience and Neurosurgery in Liverpool.

This is because your headache is likely to be a migraine — albeit in a mild form. 

Half of migraine cases are undetected, he says.

To work out if you’re a secret migraine sufferer, he suggests recording how many crystal clear, headache-free days you have each month — without any throbbing, aching, tension, fogginess or dizziness. 

If you have 25 or more, painkillers should help, as you have an occasional problem. 

Paracetamol and ibuprofen are effective, as is soluble aspirin, which is absorbed faster. 

If you have fewer than 25, it’s more likely you’re a migraine sufferer without knowing it and need more focused treatment.

Also be aware that what you think may be a sinusitis headache could be a migraine. 

Sinus problems are hugely over-diagnosed, says Dr Raju Kapoor, consultant neurologist at the National Hospital for Neurology and Neurosurgery, and the pain is often caused by migraine. 

The wrong form of treatment is given, such as antibiotics or invasive surgical procedures to clear the sinuses, which will have no effect. 

Frequent sufferers should keep a diary of their headaches and discuss it with their GP. 

YAWNING CAN BE A WARNING SIGN

Only one in five migraine sufferers has the traditional aura symptom — temporary visual and sensory problems, such as seeing zig-zag lines, nausea and sensitivity to light and sound — which lasts for about an hour before an attack, says Dr Silver. 

Clues to a person’s vulnerability to migraine include a tendency to frequent yawning, travel sickness, a hangover after just one drink and, for women, increased irritability before periods.

Experts regard stress-related headaches (tension headaches) as simply a less florid version of migraine.

Getting a sudden headache from work deadlines, a noisy office or eating sugar is a clue, says Dr Simon Shields, a consultant neurologist at Norfolk and Norwich Hospitals NHS Trust.

If you think it’s a migraine, take a painkiller, then take preventative action against more attacks, such as tackling triggers.

AVOID CHEESE, EAT BANANAS

Caffeine is a typical trigger, so try avoiding chocolate, cola and tea. 

Dr Silver says: ‘You may get a bad head for five days due to caffeine withdrawal, but after that you will have fewer headaches.’

Another common trigger is cheese. 

But sometimes a desire for chocolate or cheese may actually be a craving for sugar — which can be a sign of an impending headache, says Dr Andy Dowson, director of headache services at King’s College Hospital, London. 

He suggests eating carbohydrates, such as a banana, which will stave off symptoms by keeping blood sugar levels even. 

Dr Dowson points out that avoiding certain foods isn’t enough to prevent the attacks as trigger factors can build up over time and work in combination to cause a migraine.

So, a glass of wine, which can be a trigger for some, may not be a problem for you, but drinking after a stressful day or sleepless night may cause an attack. 

Other preventative tactics include regular meals to maintain your blood sugar level, and drinking two to three litres of fluid a day to avoid dehydration (which makes brain tissue shrink, causing pain). 

And get up at the same time every day — migraines are often triggered by disruption in routine. 

Migraines used to be referred to as ‘weekend headaches’  because they often hit on weekend mornings. 

Dr Dowson says: ‘Changing your sleep pattern suddenly has a dramatic effect on the hypothalamus, the area in the brain that is responsible for balancing hormones; this triggers a headache.’ 

Dr Silver advises sleeping in a dark room to increase production of the sleep hormone melatonin. 

Avoid watching TV in bed, as it can over-stimulate the brain. If  none of this helps, speak to  your GP about migraine-prevention medication.

SIT UP STRAIGHT TO EASE THE PAIN

If your head is pounding, then slumping in your chair is the worst thing to do, says chartered physio-therapist Sammy Margo. 

When we slump forward in a  C-shape, we kink the head upwards, which can stretch the neck and pinch nerves, causing headaches. 

It is better, Ms Margo says, to sit with your feet flat on the floor and the hips and knees straight, looking ahead.

Avoid surrounding yourself with relaxing scented candles or flowers. 

Strong odours such as perfume may stimulate the nerve system associated with head pain and cause a migraine.

WHEN COFFEE CAN ACTUALLY HELP

It can trigger migraine — but if you suffer from only occasional headaches then a cup of coffee can improve your painkiller’s effectiveness. 

Caffeine increases the absorption of many pain relievers, which is why it is found in some pills, such as Anadin Extra. 

Studies have shown various over-the-counter drugs are up to 40 per cent more effective when caffeine is added.

DON’T TAKE THE MAXIMUM DOSE

The packet may state it is safe to take, for example, up to six paracetamol a day. But if you take more than two or three doses of painkiller a week, there is a chance you will get more headaches — the ones NICE warned about. 

To avoid this, don’t take more than ten doses a month of standard painkillers or 15 a month of the migraine drug triptan.

Also, heavy use of painkillers can over-stimulate the pathways in the hypothalamus, the area of the brain that controls body temperature, hunger, thirst, sleep and other functions, says Dr Dowson. 

It’s better to look at lifestyle  factors, such as lack of sleep and too much caffeine, that may be driving your headaches.

DON'T BUY EXPENSIVE PILLS

There’s little point in spending extra on fancy-sounding pills, says Dr Andrew Lawson, consultant in pain medicine and senior lecturer at Imperial College, London.

‘There is no advantage in buying a branded, usually more expensive product instead of a generic brand,’ he says. 

‘You can’t beat “value” paracetamol caplets as a general all-round painkiller, and they cost as little as 16p.

For paracetamol to be effective for an adult, you should take two 500mg tablets four times a day. 

Avoid long-term use — more than two weeks — because it raises enzymes in the liver.’ 

Ibuprofen has anti-inflammatory properties and works well for headaches accompanied by high temperature. ‘Again, there is no advantage in buying a branded product,’ he says.

ACT QUICKLY TO LIMIT THE MISERY  

If migraines are caught early, standard painkillers can be as effective as migraine medication. 

Ibuprofen tends to work best, as it acts as an anti-inflammatory. But it won’t treat nausea, a common side-effect, so you may want a painkiller with anti-sickness properties, such as Paramax. 

The trick with all painkillers, says Dr Shields, is to take them early. Don’t wait until the symptoms have kicked in, as the drugs will be less effective. 

At the first sign of an aching head take medication.

If standard drugs don’t work for that attack, try specific migraine treatment known as triptans — and use these the next time you get an attack. 

Triptans constrict the blood vessels to stop the pain of migraine attacks. 

They are available as over-the-counter tablets, such as Imigran Recovery, and as nasal sprays.

But if you take triptans regularly, consider being prescribed preventative drugs such as betablockers, says Dr Kapoor. 

Otherwise you may start suffering rebound headaches.

If betablockers help you stay migraine-free for three to six months, you are likely to have far fewer migraine attacks in the future after coming off them. 

For the nausea associated with migraines, you can try prescription anti-sickness medicines. See your GP for advice.

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Why Americans Don't Sleep Well

Amen. JR

Why are 70 million Americans having trouble getting a good night’s sleep? Let us count the ways:

We are over-caffeinated (coffee, soft drinks, energy drinks, snacks) and over-medicated (prescription and over-the-counter drugs, including alcohol), wreaking havoc with slumber patterns.

We are over-wired (video games, Web browsing, social media, texting) and overstressed (money, work, relationships, overloaded schedules), making us too restless to doze off when we should.

We are overworked (longer hours, night shifts incompatible with our biological clocks) and overweight (perhaps a chicken-or-egg deal, as different studies have found that one leads to the other).

And then there’s societal pressure, what nationally recognized sleep expert Dr. Mark Mahowald calls “the pervasive, erroneous attitude that sleep is not a biological imperative, that it is negotiable. We have raised sleep deprivation to a badge of honor.”

The effects might outnumber the causes, and are hardly as benign as many of us might think. “Any degree of sleep deprivation will impair performance: behind the wheel, in the classroom or workplace,” Mahowald said.

He added that the Bhopal, Challenger, Exxon Valdez and Three Mile Island disasters “all are officially attributed to problems from sleep deprivation. But the biggest risk of sleep deprivation is car crashes, period.”

No wonder the number of accredited sleep centers has risen nationwide by 630 percent in just 15 years. And while sleep study results have been all over the map and sometimes contradictory, experts such as local doctors Mahowald and Michael Schmitz know a lot more than researchers did even a decade ago.

Effects:

• With sleep deprivation, some glucose metabolism problems might predispose one to diabetes. And if so, a consequence could be heart disease and stroke.

• With insomnia, there is no evidence of long-term physical problems or links to other diseases. But insomnia results in poorer quality of life and work absences and can lead to depression.

• There is some evidence that severe sleep apnea can lead to hypertension, heart problems and a higher risk of strokes.

Solutions:

• Improving sleep hygiene -- avoiding late eating and drinking, keeping the room cool and dark, winding down before bedtime -- can improve or resolve transient or acute insomnia but probably not chronic insomnia.

• For chronic insomnia, cognitive behavioral therapy is equally as or more effective than medications. Medication often is useful for acute insomnia.

• Naps can help -- except when they don’t. “We discourage napping when anyone has problems falling or staying asleep at night, which might be an untreated sleep disorder,” said behavioral sleep specialist Schmitz. “We encourage power naps, 30 minutes or less, when folks can’t stay awake or will have late-night events.”

• See your doctor if: You have had difficulty falling and staying asleep for more than a week. Or if you snore, have frequent awakenings and are reporting sleepiness during the day. Anyone with apnea symptoms should seek treatment.

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Rea
Read more here: http://www.macon.com/2012/04/09/1981741/americans-are-too-busy-drink-too.html#storylink=cpy

Coffee drinking during pregnancy won't lead to a sleepless baby

Caffeine consumption among expectant or new mothers does not appear to affect the nighttime sleeping habits of their newborns, new Brazilian research indicates.

The conclusion is based on an analysis of sleeping patterns among more than 4,200 infants until the age of 3 months, in light of the caffeine-consumption habits of their mothers both before and after delivery.

Researchers looked at two beverages: coffee and mate, a hot tea-like beverage popular in their area.

The team, led by study author Dr. Ina Santos of the postgraduate program in epidemiology at the Federal University of Pelotas in Brazil, reports its observations online and in the May print issue ofPediatrics.

The authors note that it is very common for newborns to experience nighttime awakenings, and that caffeine consumption has long been linked to sleep disruption and insomnia among adult drinkers.

To see whether caffeine consumption among pregnant women and nursing mothers affects their child's sleep, Santos' team tracked more than 4,200 infants who were born in 2004 in the city of Pelotas, with a specific focus on 885 infants within that group.

All the new mothers were interviewed at the hospital immediately after delivery and then three months later to gauge their caffeine-drinking habits. Heavy coffee drinkers were defined as those who consumed 300 milligrams or more of caffeine per day, either via coffee or some other caffeinated beverage.

According to the Mayo Clinic, two to four cups of brewed coffee contain between 200 and 300 milligrams of caffeine.

All the newborns were examined at birth, with follow-up exams conducted at three months. At that point, the mothers provided details on their child's sleep habits during the prior 15 days, including total day and night sleep hours and bed-sharing practices.

Defining night awakenings as being any time parents were awakened by a child's arousal, the researchers also asked parents to tally the frequency of their child's nighttime waking episodes and indicate any apparent causes for such awakenings. Frequent awakening was defined as a child waking up three or more times per night.

Mothers also made an overall assessment of the quality of their baby's sleep habits.

All but one of the mothers regularly consumed some caffeine. About one in five was considered a heavy caffeine drinker during pregnancy, and more than 14 percent continued to drink caffeine heavily as their newborns reached 3 months of age.

As for the babies, nearly 14 percent were frequent nighttime wakers.

Although there was some indication that nighttime wakening was more prevalent among babies whose mothers were heavy caffeine consumers during pregnancy and nursing, the connection was not statistically significant.

The researchers concluded that there was no evidence that caffeine consumption, at any particular level, could be linked to sleep-pattern disruptions among the infants.

Lona Sandon, a registered dietitian and assistant professor of clinical nutrition at the University of Texas Southwestern in Dallas, said although caffeine consumption among pregnant women and new mothers has long been a concern among pediatricians, it has certainly never risen to the level of alarm over alcohol consumption or cigarette use.

"Coffee drinking in that situation has never been perceived as evil or bad," she said. "But, depending on the pediatrician, oftentimes mothers are encouraged to limit caffeine intake during pregnancy, often to just one cup of coffee a day -- or to stop drinking it altogether. And that's because it's a central nervous system stimulant that can increase the baby's heart rate in utero, and can cause some distress. And then, after delivery, the baby might be getting the caffeine through the breast milk."

"But it should be pointed out that the 300 milligrams of coffee they're talking about here is really not such an outlandish amount," Sandon said. "It's really about three cups of a standard six- to eight-ounce cup of coffee. And that's just one grande Starbucks, really."

"At that amount, it could be that coffee drinking is more likely a problem for the mother than for the infant," she added. "The child's sleep patterns might not be disrupted. But it could actually be disrupting the mother's sleep patterns at a time when it's already difficult for the mother to get adequate rest."

Dr. Aparajitha Verma, medical director of the Methodist Hospital Sleep Disorder Center in Houston and an assistant professor in the neurology department at Methodist Neurological Institute, cautioned that nailing down maternal caffeine consumption's specific impact on newborns is an extremely tricky endeavor.

"Nighttime wakening among babies that age can be due to so many different things," she said. "So to tease out caffeine's role is going to be very difficult. I think it's a valid concern, and there certainly might be a connection. Caffeine's half-life is typically five to seven hours, and it's well known to cause sleep disruption among adults. But whether that translates into trouble among these women's infants is something that clearly we just don't know yet."

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