Hot weather may play a role in concussions - Even a 2 percent loss in body volume is important!

A study showed that hot weather and dehydration can increase a person's chance of having a concussion.

A loss of just two percent of the body's water volume to dehydration -- a feat easily achieved during prolonged exercise in hot weather -- can lead to a significant reduction in the amount of cerebrospinal (CSF) fluid that a person has. CSF acts as a cushion to protect the brain from hitting against the inside of the skull during jarring movements. For football players, games conducted in hot and humid conditions could present the perfect storm of risk factors to up their chances for a concussion.

Researchers at the University of Windsor investigated whether the incidence of concussion increased along with the temperature. J. Craig Harwood presented the research team's findings in a poster session on Monday, April 28, at the Experimental Biology Meeting. Experimental Biology is an annual meeting comprised of more than 14,000 scientists and exhibitors from six sponsoring societies and multiple guest societies. With a mission to share the newest scientific concepts and research findings shaping current and future clinical advances, the meeting offers an unparalleled opportunity for exchange among scientists from throughout across the United States and the world who represent dozens of scientific areas, from laboratory to translational to clinical research.www.experimentalbiology.org

Harwood et al. compiled data on 420 NCAA FBS game-time concussions that occurred during games played outside over a five year period (2008-2012). They also looked at environmental conditions (temperature, humidity, and wind speed) during those games.

From the authors: "The relationship between hydration status and injury occurrence, such as skeletal muscle cramps, is well known, but more information is needed regarding physiological status and the risk of more severe injury like concussion. We were initially interested in the link between dehydration and concussion frequency/severity, however this type of observation was obviously problematic (e.g., measuring game time hydration status in thousands of athletes prior to head injury). Hydration status was unknown, and factors like helmet function (which is compromised in cold conditions) may hide true differences.

We hypothesized that if a relationship existed, we would be able to observe an increase in concussion frequency during games that took place under extreme conditions. But given the primary playing season (i.e., Fall), very few games were played in environmental extremes. Additionally, the high level of competition likely insured that athletes were well prepared for games in all conditions. In the end, the overall rates of concussions were consistent across game time temperatures, but a link between dehydration and concussion rate may still exist.

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Study: Sunny climates may reduce ADHD

A study indicates many risk factors for ADHD, and interestingly notes that sunny and warm climates may reduce the condition.

Attention-deficit/hyperactivity disorder, or ADHD, is the most common childhood psychiatric disorder. Scientists do not know what causes it, but genetics play a clear role. Other risk factors have also been identified, including premature birth, low birth weight, a mother's use of alcohol or tobacco during pregnancy, and environmental exposures to toxins like lead.

ADHD is characterized by an inability to focus, poor attention, hyperactivity, and impulsive behavior, and the normal process of brain maturation is delayed in children with ADHD. Many individuals with ADHD also report sleep-related difficulties and disorders. In fact, sleep disorder treatments and chronobiological interventions intended to restore normal circadian rhythms, including light exposure therapy, have been shown to improve ADHD symptoms.

Estimates suggest that the average worldwide prevalence of ADHD ranges from about 5 to 7%, but it also varies greatly by region. A simple visual comparison of data maps released by the U.S. Centers for Disease Control and Prevention and the U.S. Department of Energy that display ADHD prevalence rates by state and solar intensities (sunlight) across the country, respectively, reveals an interesting pattern indicative of an association. So does this mean that there could be an identifiable relationship between ADHD prevalence rates and the sunlight intensity levels of particular regions?

The accumulation of these points led Dr. Martijn Arns and his colleagues to systematically and scientifically investigate this question. They collected and analyzed multiple data-sets from the United States and 9 other countries. Reporting their findings in the current issue of Biological Psychiatry, they did find a relationship between solar intensity and ADHD prevalence.

Even after controlling for factors that are known to be associated with ADHD, both U.S. and non-U.S. regions with high sunlight intensity have a lower prevalence of ADHD, suggesting that high sunlight intensity may exert a 'protective' effect for ADHD.

To further validate their work, they also looked at this same relationship with autism and major depressive disorder diagnoses. They found that the findings were specific to ADHD, with no associations observed between the other two disorders.

"The reported association is intriguing, but it raises many questions that have no answers," commented Dr. John Krystal, Editor of Biological Psychiatry. "Do sunny climates reduce the severity or prevalence of ADHD and if so, how? Do people prone to develop ADHD tend to move away from sunny climates and if so, why?"

As with all scientific research, further work is necessary, including a prospective replication of these findings. It is also important to realize that this data reflects only an association -- not a causation -- between ADHD and solar intensity levels so worried parents should not start planning cross-country moves.

However, these findings do have significant implications, explains Dr. Arns. "From the public health perspective, manufacturers of tablets, smartphones and PCs could investigate the possibility of time-modulated color-adjustment of screens, to prevent unwanted exposure to blue light in the evening."

"These results could also point the way to prevention of a sub-group of ADHD, by increasing the exposure to natural light during the day in countries and states with low solar intensity. For example, skylight systems in classrooms and scheduling playtime in line with the biological clock could be explored further."

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Sleep disorders in children may be caused by winter viruses

Sleep disorders in children related to breathing during sleep may be due to winter viruses.

A good night's sleep is important to our children's development. But with the first day of school just passed, many children are at increased risk for sleep breathing disorders that can impair their mental and physical development and hurt their academic performance.

A study conducted in North America in 2011 showed that the frequency of sleep-disordered breathing increases in the winter and spring. Until now, researchers believed asthma, allergies and viral respiratory infections like the flu contributed to disorders that affect children's breathing during sleep.

Now, in a new study conducted at the Pediatric Sleep Center at the Tel Aviv Sourasky Medical Center and published in the journal Sleep Medicine, Riva Tauman and her fellow researchers of the Sackler Faculty of Medicine at Tel Aviv Univ. have shown that asthma and allergies do not contribute to pediatric sleep-disordered breathing. Viruses alone, they say, may be responsible for the seasonal variation seen in children.

The researchers say the study has broad implications for the treatment of sleep-breathing disorders in children, bolstering the idea that the time of year is relevant when treating children for sleep-disordered breathing in borderline cases.

Blowing hot and cold

"We knew from research and clinical practice that sleep-disordered breathing in children gets worse during the colder months," Tauman says. "What we didn't expect is that the trend has nothing to do with asthma or allergies."

"Sleep-disordered breathing" is a blanket term for a group of disorders. One of the common disorders is obstructive sleep apnea, in which the upper airway becomes blocked, usually by enlarged tonsils or adenoids, causing snoring and, in more severe cases, breathing pauses that lead to poor-quality and fragmented sleep and decreased oxygen and elevated carbon dioxide levels in the bloodstream.

In the long term, sleep-disordered breathing in children can cause stunted growth, heart disease and neurocognitive problems associated with diminished school performance, impaired language development and behavioral issues.

In their study, Tauman and her Sackler Faculty of Medicine colleagues Michal Greenfeld and Yakov Sivan statistically analyzed the cases of more than 2,000 children and adolescents who were referred to the sleep center to be tested for suspected sleep-disordered breathing between 2008 and 2010. Confirming earlier results of a 2011 study of five- to nine-year-olds, the researchers found that pediatric sleep-disordered breathing is worse in the winter — which in Israel they defined as from November to March — than in the summer. The seasonal variability is most apparent in children less than five years old, they found.

The researchers also found that wheezing and asthma do not contribute to the trend.

Based on their findings, the researchers speculate that viral respiratory infections — which are more prevalent in younger children and during colder months — are the major contributor to the seasonal variability seen in pediatric sleep-disordered breathing.

Taking the long view

If the sleep clinic tests had all been conducted in the winter, the researchers estimate that seven percent more children would have been diagnosed with sleep-disordered breathing. Seven percent fewer would have been diagnosed if all the tests had been done in the summer, they estimate.

"Our study suggests that if a child comes into the sleep laboratory in the winter with a mild case, I may consider not treating him. I can assume he will be better in the summer," says Tauman. "But if he has only mild symptoms in the summer, I can assume they are more severe in the winter."

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Lightning may trigger migraines

Researchers found that people are more likely to have a migraine headache on days when lightening is striking somewhere around their home.

Weather has long been considered one of many potential migraine triggers, but a new study links lightning, specifically, to the onset of the severe headaches that plague more than 28 million Americans.

Based on headache logs and weather data for Ohio and Missouri, researchers found that people were 28 percent more likely to experience a migraine on days when lightning struck within 25 miles of their home.

"We're very surprised and very happy with the results in that this is the first study to link lightning to migraines," said Dr. Vincent Martin, the study's senior author from the University of Cincinnati College of Medicine in Ohio.

Migraines are severe headaches - sometimes accompanied by light sensitivity, visual hallucinations or nausea - that can disable a person for hours or even days at a time. The majority of migraine sufferers are women.

Martin told Reuters Health that a migraine may result from a person experiencing certain "triggers," such as stress, lack of sleep and dehydration.

Previous research has also found links between the onset of migraines and high barometric pressure, high temperatures and high humidity.

Most of the past studies looking at weather and migraines, however, relied on an individual's observations and did not always account for other, possibly unseen, local weather conditions, the researchers write in the journal Cephalalgia.

For the new study, they used information collected from three sensors that track lightning near Cincinnati, Ohio, and five sensors near St. Louis, Missouri. Those sensors allowed the researchers to know where and when lightning struck and the intensity of each strike.

They also used the headache diaries from two previous studies of 90 migraine sufferers in those areas who were between 18 and 65 years old. In those diaries, the participants recorded their headaches for three to six months.

After comparing the weather data with the headache journals, the researchers found that a lightning strike within 25 miles of a person's house was linked to a 31 percent increased risk of any kind of headache, and a 28 percent increased risk of the more severe migraine headache.

Martin said that could mean an extra one to three migraines per month for an individual, but he added that it depends on the person and the weather.

As for how lightning might affect migraine occurrences, Martin said it could be that the electromagnetic waves and ozone created by the lightning have something to do with it.

"The other theory is that when these thunderstorms roll in they can create more allergy spores in the environment," he said, which could create a problem for some people.

But the researchers cannot say for certain that lightning causes migraines, even though they used a computer model to account for other meteorological changes that occur during a thunderstorm.

In an accompanying editorial, Dr. Hayrunnisa Bolay of Gazi University in Ankara, Turkey, cautioned that the study had limitations, including its failure to account for the participants' own individual risk factors.

"In brief, one can only conclude that weather conditions associated with lightning have the potential to induce headache in migraine patients," she wrote.

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Study Claims Sleep Apnea Worsens during Winter Months

Countless Americans suffer from sleep apnea, a dangerous sleep disorder that causes sufferers to stop breathing numerous times throughout the night. Most people suffering from the condition must cope with frequent waking, daytime fatigue and snoring. Now, a recent study out of Brazil suggests these symptoms may worsen when the mercury drops.

More Severe During the Winter

According to research conducted at Universidade Federal do Rio Grande do Sul, weather changes can have a very real impact on the way patients experience sleep apnea. Over the course of a decade, researchers tested 7,500 patients for at least one night to see how many times each stopped breathing. Ultimately, they found that subjects who were tested during the coldest months of the year experienced more nighttime disturbances (18) than those who were tested during the warmer months (15).

Additionally, the study found that, while only 28 percent of subjects were found to have severe sleep apnea during the warm season, 34 percent suffered from severe sleep apnea during the colder parts of the year.

Although researchers weren’t able to determine why cold weather might make the sleep disorder worse, they theorized that wood burning might irritate the condition, as might heating units which can dry the air and dehydrate the sinuses.

Seeking Treatment

Regardless of the season, sleep apnea remains a serious condition that can drastically reduce the quality of a sufferer’s life. The condition has also been linked to numerous health problems, including obesity and dementia. Normally, people find 100 percent relief when they receive CPAP treatments; however, many people suffer unknowingly with the sleep disorder for years before they get help.

In the end, only a sleep physician can diagnose a patient with sleep apnea. Typically, patients are expected to sleep overnight at a sleep clinic; however, these days, more and more physicians are using at-home sleep testing equipment that allows patients to be tested while in the comfort of their own beds.

Red wine and weather may trigger migraines

There are many triggers for migraines.  I frequently tell patients that  people who have sensitive brains have migraines.  It sounds very general and unhelpful, but the number of triggers are as varied as there are people.

For those who enjoy a little wine, It's good to know that not all red wines can trigger migraine. I agree that those who are sensitive should start with the red wines with the lowest tannins.

JR

New research may help answer the age-old question of whether factors such as the weather or drinking red wine can set off a migraine.

According to research presented this week at the annual meeting of the American Headache Society in Los Angeles, both of these factors can trigger the excruciating headaches, but not for all people and not all the time.

One small study looked at 33 adults in Brazil who considered themselves regular red-wine drinkers and believed that the beverage had caused migraines in the past. All were asked to drink half a bottle (375 milliliters) of a Malbec, Tannat, Cabernet Sauvignon and Merlot wine from South America at least four days apart.

Although most participants reported having a migraine at least once within 12 hours of drinking wine, some wines were more to blame than others -- specifically Tannat and Malbec. Both varieties contain higher levels of flavonoids known as tannins, which provide red wine's rich coloring.

Although the study was not a controlled one, conceded study lead author Dr. Abouch Krymchantowski, "I concluded that the wines with the highest content of tannins -- Tannat and Malbec -- are those which triggered migraines more frequently."

People who point to red wine as a migraine trigger but still like to drink it should choose wines with the lowest tannin content, added Krymchantowski, who is director and founder of the Headache Center in Rio de Janeiro.

"It's a small study, but it confirms what we hear from patients: Wine can trigger migraines, but not necessarily all the time," said Dr. Brian Grosberg, an assistant professor of neurology at Albert Einstein College of Medicine and co-director of the inpatient headache program at Montefiore Headache Center in New York City.

Krymchantowski would now like to see data on whether wines from different regions -- Australia and France, for example -- would behave differently in people who suffer migraines.

A second study being presented at the meeting found that outside temperature also can trigger migraines, especially among people who are more sensitive to temperature.

Sixty-six migraine patients were asked to keep a headache diary over the course of a year. Temperature change was linked with mild headaches 21 percent of the time, but only 5 percent of the time for more severe headaches.

And the association seemed more closely linked to cold rather than hot days.

"The study provides pioneering evidence that headaches are associated more with temperature among those with subjective temperature sensitivity than those without," said study lead author Dr. Shuu-Jiun Wang, deputy head of the Neurological Institute at Taipei Veterans General Hospital and a professor of neurology at National Yang-Ming University School of Medicine in Taipei, Taiwan.

"If patients report temperature sensitivity, physicians should pay more attention and may adjust preventive agents in certain seasons ... for these patients," he added.

This study, too, confirms patients' accounts and even previous research findings that a rise in temperature increased the incidence of headaches, said Grosberg, who was not involved in either study. But often it's not just one factor that starts a migraine attack, but two or more together.

"Sometimes it's one strong trigger, but usually it's a combination of two or more triggers that will precipitate an attack," Grosberg said.

Triggers could include menstrual cycles, lack of sleep, inclement weather and changes in barometric pressure.

It's not clear from these studies if other triggers may have played a role in the onset of migraines, Grosberg said.

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