Adolescents stress more with poor sleep

Date: January 14, 2016 

Source: University of Alabama at Birmingham

Summary: 

Cortisol levels that indicate increased stress response are higher in adolescents with sleep problems.

Student asleep in class (stock image).

Credit: © WavebreakMediaMicro / Fotolia

A new study from the University of Alabama at Birmingham indicates that adolescents who experience sleep problems and longer sleep duration are more reactive to stress, which could contribute to academic, behavioral and health issues.

Existing studies show that nearly 70 percent of U.S. adolescents do not receive sufficient sleep. It is also known that insufficient sleep and sleep problems contribute to cognitive problems and poor physical health over time, possibly because of disruptions in a key part of the neuroendocrine system that controls reactions to stress and regulates many body processes -- the hypothalamic-pituitary-adrenal axis, or the HPA axis.

The relationship between sleep and the HPA axis has been studied in both children and adults; but little is known about this link during adolescence, which is a key period of time, as both sleep and the HPA axis are undergoing significant developmental changes related to puberty.

Sylvie Mrug, a psychology professor in UAB's College of Arts and Sciences, and her colleagues from UAB and Arizona State University sought to further explore the relationship between sleep and reactivity to stress, specifically as it relates to HPA-axis activity, in adolescents.

The researchers examined two dimensions of sleep -- sleep duration and sleep problems from the perspectives of adolescents and their parents, as well as cortisol levels before and after social stress. The team also looked at how the results varied based on gender.

"We chose to look at sleep patterns in urban African-American adolescents, due to information we understood from earlier research in the field," Mrug said. "This particular population is more likely to experience insufficient sleep, and their functioning is more negatively affected by lower sleep quality, so we knew that finding results for this demographic could be especially important."

Eighty-four adolescents with an average age of approximately 13 took part in the study. During their visit to the research lab, participating adolescents were given the children's version of a common stress test, called the Trier Social Stress Test, to measure their physiological responses to stress. This test involves speaking and computing mental math problems in front of an audience. Saliva samples were taken from each participant in order to test cortisol levels before and after the stress test.

Participants then reported on their bed times and wake times and any sleep problems, such as insomnia, daytime sleepiness and general sleep quality, during a regular week. Parents of the adolescents were asked to report on their children's sleep as well.

The adolescents most commonly reported the following sleep problems: the need for multiple reminders to get up in the morning, not having a good night's sleep, feeling tired or sleepy during the day, and not being satisfied with their sleep.

The researchers looked at the cortisol levels of the adolescent participants. Cortisol release during and after the stressful lab test was higher for adolescents who reported more sleep problems and longer sleep duration, and whose parents reported longer sleep duration.

"The result of higher cortisol levels in adolescents experiencing sleep problems was exactly what we expected to see," Mrug said. "We were, however, surprised that longer sleep duration predicted a stronger cortisol response, because previous studies linked shorter sleep duration with higher cortisol levels. Generally, less sleep is related to poor outcomes, not the other way around. In this case, this unexpected result could be explained by considering that longer sleep duration does not necessarily reflect higher-quality sleep, but instead may serve as another indicator of sleep problems, at least among urban adolescents."

The effects of sleep problems on greater cortisol release during stress were stronger in females than in males, suggesting that adolescent girls may be more sensitive to disrupted and poor quality sleep.

"Overall, the results of our study confirm what we originally hypothesized -- that sleep problems induce greater response to stress in adolescents," Mrug said. "It's important that we know this, because the enhanced and prolonged activation of the HPA axis in response to stress could contribute to more health problems. The urban African-American youth whom we studied may be particularly negatively affected by poor sleep because they are more likely to experience uncontrollable stress related to community and school violence. We want to do all that we can to understand ways we can help ensure better cognitive, emotional and physical health outcomes for these adolescents."

Mrug's study was published online in Physiology and Behavior in December and will appear in print in March 2016.

Story Source:

The above post is reprinted from materials provided by University of Alabama at Birmingham. Note: Materials may be edited for content and length.

Journal Reference: 

Sylvie Mrug, Anna Tyson, Bulent Turan, Douglas A. Granger. Sleep problems predict cortisol reactivity to stress in urban adolescents.Physiology & Behavior, 2016; 155: 95 DOI:10.1016/j.physbeh.2015.12.003

Cite This Page: 

University of Alabama at Birmingham. "Adolescents stress more with poor sleep." ScienceDaily. ScienceDaily, 14 January 2016. <www.sciencedaily.com/releases/2016/01/160114164001.htm>.

Blueberries, citrus fruits, red wine associated with reduced erectile dysfunction

Date: January 13, 2016 

Source: University of East Anglia 

Summary: 

Flavonoid-rich foods are associated with a reduced risk of erectile dysfunction, according to a new study. Of all the different flavonoids, Anthocyanins (found in blueberries, cherries, blackberries, radishes and blackcurrant), flavanones and flavones (found in citrus fruits) were found to offer the greatest benefits in preventing the condition. This research shows that eating a flavonoid-rich diet is as good for erectile function as briskly walking for up to five hours a week.

Flavonoid-rich foods are associated with a reduced risk of erectile dysfunction -- according to a new collaborative study from the University of East Anglia (UEA) and Harvard University.

Research published in The American Journal of Clinical Nutrition reveals that eating foods rich in certain flavonoids is associated with a reduced risk of erectile dysfunction in men, with the greatest benefit in those under 70.

Of all the different flavonoids, Anthocyanins (found in blueberries, cherries, blackberries, radishes and blackcurrant), flavanones and flavones (found in citrus fruits) were found to offer the greatest benefits in preventing the condition.

It is already known that increased exercise can improve erectile function, but this research shows that eating a flavonoid-rich diet is as good for erectile function as briskly walking for up to five hours a week.

The study also showed that a higher total fruit intake was associated with a 14 per cent reduction in the risk of erectile dysfunction. And that a combination of consuming flavonoid-rich foods with exercise can reduce the risk by 21 per cent.

The study was carried out by nutrition departments at the Harvard TH Chan School of Public Health and UEA's Norwich Medical School.

Lead researcher Prof Aedin Cassidy from UEA said: "We already knew that intake of certain foods high in flavonoids may reduce the risk of conditions including diabetes and cardiovascular disease. This is the first study to look at the association between flavonoids and erectile dysfunction, which affects up to half of all middle-aged and older men.

"Flavonoids are present in many plant-based foods and drinks including fruits, vegetables, tea, herbs and wine. We examined six main types of commonly consumed flavonoids and found that three in particular -- anthocyanins, flavanones and flavones -- are beneficial.

"Men who regularly consumed foods high in these flavonoids were 10 per cent less likely to suffer erectile dysfunction. In terms of quantities, we're talking just a few portions a week."

More than 50,000 middle aged men were included in this large population based study. They were asked about their ability to have and maintain an erection sufficient for intercourse -- dating back to 1986. Data on dietary intake was also collected every four years.

The research team took into account a range of factors such as body weight, physical activity, amount of caffeine consumed, and whether the participants smoked. The research was also restricted to men who were otherwise in good health.

More than one third of the men surveyed reported suffering new onset erectile dysfunction. But those who consumed a diet rich in anthocyanins, flavones and flavanones were less likely to suffer the condition.

Prof Cassidy said: "The top sources of anthocyanins, flavones and flavanones consumed in the US are strawberries, blueberries, red wine, apples, pears, and citrus products."

"We also found that the benefits were strongest among younger men," she added.

The team also looked at other lifestyle factors and found that men who consumed a high intake of anthocyanins and flavanones and who were also physically active had the lowest risk of erectile dysfunction.

Dr Eric Rimm, senior author on the study and a Professor of Epidemiology and Nutrition at the Harvard TH Chan School of Public Health, said: "As well as improving sexual health for middle-aged men, there is another important benefit linked to heart health. Erectile dysfunction is often an early barometer of poor vascular function and offers a critical opportunity to intervene and prevent cardiovascular disease, heart attack and even death.

"Men with erectile dysfunction are likely to be highly motivated to make healthier lifestyle choices, such as exercising more and eating the right foods -- which would greatly benefit their long-term cardiovascular health as well."

Story Source:

The above post is reprinted from materials provided by University of East Anglia. Note: Materials may be edited for content and length.

Journal Reference: 

A. Cassidy, M. Franz, E. B. Rimm. Dietary flavonoid intake and incidence of erectile dysfunction. American Journal of Clinical Nutrition, 2016; DOI: 10.3945/ajcn.115.122010

Cite This Page: 

University of East Anglia. "Blueberries, citrus fruits, red wine associated with reduced erectile dysfunction." ScienceDaily. ScienceDaily, 13 January 2016. <www.sciencedaily.com/releases/2016/01/160113160654.htm>.