Tag: stress

Categories : Cardiovascular Disease GenderTags :

Female and Male Hearts may Respond Differently to Noradrenaline

On By ModernMedia
Source: Wikimedia CC0

A new study published in Science Advances shows that female and male hearts respond differently to the stress hormone noradrenaline. The study in mice may have implications for human heart disorders like arrhythmias and heart failure and how different sexes respond to various drugs.

Using fluorescence imaging, the researchers were able to see in real time and in vivo how a mouse heart responds to hormones and neurotransmitters, including noradrenaline.

The results reveal that male and female mouse hearts respond uniformly at first after exposure to noradrenaline. However, some areas of the female heart return to normal more quickly than the male heart, producing differences in the heart’s electrical activity.

“The differences in electrical activity that we observed are called repolarisation in the female hearts. Repolarisation refers to how the heart resets between each heartbeat and is closely linked to some types of arrhythmias,” said Jessica L. Caldwell, first author of the study.

“We know that there are sex differences in the risk for certain types of arrhythmias. The study reveals a new factor that may contribute to different arrhythmia susceptibility between men and women,” Caldwell said.

Methods

The novel imaging system uses a genetically modified ‘CAMPER’ mouse to emit light during a very specific chemical reaction in the heart: cAMP binding.

The cAMP molecule (an abbreviation of cyclic adenosine 3′,5;-monophosphate) is an intermediate messenger that turns signals from hormones and neurotransmitters, including noradrenaline, into action from heart cells.

The light signals from the CAMPER mouse are transmitted by a biosensor that uses a fluorescence signal that can be picked up at high speed and high resolution by a new imaging system specially designed for hearts. This allows the researchers to record the heart’s reaction to noradrenaline in real time, along with changes in electrical activity.

This new imaging approach revealed the differences in the breakdown of cAMP in female and male mice and the associated differences in electrical activity.

Including female mice leads to discoveries

The researchers had not planned to study sex-based responses, according to Crystal M. Ripplinger, senior author of the study. But the researchers started seeing a pattern of different reactions, which led them to realise the differences were sex-based.

When Ripplinger started her lab at the UC Davis School of Medicine over a decade ago, she exclusively used male animals. That was the norm for most research at the time. But several years ago, she began including male and female animals in her studies.

“Sometimes the data between the two sexes is the same. But if the data start to show variation, the first thing we do is look at sex differences. Using both male and female mice has revealed clues into differences we would never have suspected. Researchers are realising you can’t extrapolate to both sexes from only studying one,” Ripplinger said.

She notes that with the current study, it’s not clear what the differences in cAMP and electrical activity may mean.

“The response in the female mice may be protective – or it may not. But simply documenting that there is a measurable difference in the response to a stress hormone is significant. We are hoping to learn more in future studies,” Ripplinger said.

Source: University of California – Davis Health

Categories : Mental HealthTags :

Politics Makes People Sick – Literally

On By ModernMedia
Photo by Andy Feliciotti on Unsplash

According to a new US study, all the political jockeying is harmful to our health, has been for some time, and even a change in party power didn’t help.

Political scientist Kevin Smith followed up a landmark 2017 survey study where he measured the effects of the political climate on Americans’ physical, social, mental and emotional health. Smith repeated the same 32-question survey twice in 2020 – two weeks prior to the election, and two weeks after. The 2020 findings mirrored the 2017 results, and again found that a large proportion of American adults blame politics for causing them stress, loss of sleep, fractured relationships and more.

Similar to the 2017 findings, the results of the 2020 surveys, published in PLOS One, showed that an estimated 40% of Americans identified politics as a significant source of stress. Between a fifth and a third of US adults also blamed politics for causing fatigue, feelings of anger, loss of temper and triggering compulsive behaviours. About a quarter of adults reported they’d given serious consideration to moving because of politics.

That the results remained mostly stable after nearly four years is cause for alarm, Smith said.

“This second round of surveys pretty conclusively demonstrates that the first survey was not out of left field – that what we found in that first survey really is indicative of what many Americans are experiencing,” Smith, chair and professor of political science, said. “It’s also unpleasant to think that in that span of time, nothing changed. A huge chunk of American adults genuinely perceive politics is exacting a serious toll on their social, their psychological and even their physical health.”

Smith repeated the survey with the same group of people both before and after the election to see if the election’s outcome would recast people’s perceptions.

“We wondered if a change in presidency, which indeed was the case, would shift attitudes, and the short answer is no,” Smith said. “If anything, the costs that people perceive politics is exacting on their health increased a little bit after the election.”

Smioth was most surprised at the repeated finding that 5% of Americans blame politics for having suicidal thoughts.

“One in 20 adults has contemplated suicide because of politics,” Smith said. “That showed up in the first survey in 2017, and we wondered if it was a statistical artifact. But in the two surveys since, we found exactly the same thing, so millions of American adults have contemplated suicide because of politics. That’s a serious health problem.”

Those most likely to be negatively affected by politics were younger, more often Democratic-leaning, more interested in politics and more politically engaged.

“If there’s a profile of a person who is more likely to experience these effects from politics, it’s people with those traits,” Smith said.

This could mean problems for democracy if this trend continued. Smith suggested investigating whether civic education had a positive effect, as those who were more knowledgeable about politics seemed to be less affected.

Source: University of Nebraska

Categories : Addiction COVIDTags :

No Smoking Uptick in COVID Pandemic – Unlike Other Disasters

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Photo by Elsa Olofsson on Unsplash


Unlike other population-level stressful events such as natural disasters, COVID has not resulted in a net increase in smoking, according to a new study from the International Tobacco Control (ITC) Project, at the University of Waterloo.

However, the researchers also found that although nearly half of smokers reported that COVID caused them to consider quitting, the vast majority of smokers did not change their smoking habits during the early phase of the COVID pandemic.

Stress is known to be a significant risk factor for smoking, especially in females. The study surveyed 6870 smokers and vapers in  Australia, Canada, England, and the United States between April and June 2020. The team investigated the association between COVID and thoughts about quitting smoking, changes in smoking, and factors related to positive changes such as attempting to quit or reducing smoking.

Only 1.1 per cent of smokers in the four countries attempted to quit and 14.2 percent reduced smoking, but this was offset by the 14.6 percent who increased smoking, with 70.2 percent reported no change.

“It is important to note that population-level stressful events, such as 9/11 and natural disasters, have often led to increased smoking,” said Geoffrey Fong, professor of psychology at Waterloo and principal investigator of the ITC Project. “So, our findings that there was no net increase in smoking in response to COVID may actually represent a positive result for public health.”

The study found that those who considered quitting smoking due to COVID were mostly females, ethnic minorities, those under financial stress, current vapers, less dependent smokers, those with greater concern about personal susceptibility of infection, and those who believed COVID is more severe for smokers.

According to study co-author Fong, this latter finding may explain why a significant uptick in smoking was seen in the COVID pandemic, compared to past tragedies.

“Unlike other population stressors such as earthquakes, which are unrelated to smoking, COVID severity is indeed linked to smoking,” Fong said. “Public health officials have mentioned the link as yet another reason for smokers to quit, and over 80 percent of smokers across the four countries believed that smoking made COVID more severe. And this led to the lack of an increase in smoking, unlike what we have seen after other tragedies.”

Source: EurekAlert!

Journal information: Gravely, S., et al. (2021) Smokers’ cognitive and behavioural reactions during the early phase of the COVID-19 pandemic: Findings from the 2020 ITC Four Country Smoking and Vaping Survey. PLOS ONE. doi.org/10.1371/journal.pone.0252427.

Categories : Mental HealthTags :

Social Media Breaks Don’t Relieve Boredom or Stress

On By ModernMedia
Photo by Tracy le Blanc from Pexels

A team of researchers has found that workers using their smartphone to take short breaks do not find reductions in boredom or fatigue. 

Smartphones have had an inescapable impact on society, and allow users to engage with a variety of apps. Anecdotal evidence also suggests that people use their phones in other ways as well, such as to alleviate boredom or to reduce stress. The researchers noted that many people use their smartphones to take short breaks from their work—and they wondered if doing so actually helped with boredom or reduced stress.

To find out, researchers at Radboud University’s Behavioural Science Institute in The Netherlands recruited 83 PhD candidates, each of whom were asked to report their level of boredom and fatigue every hour while they were working. They also received a smartphone app that logged its usage.

In comparing phone usage with self-reported levels of boredom and fatigue, the researchers were able to track the volunteers’ use of their phones to deal with boredom or fatigue. They found that not only did using their phones in such a manner not alleviate boredom or fatigue, in many cases it in fact made things worse. Volunteers who described themselves as more bored or more fatigued than others in the study did not take longer smartphone breaks than those feeling less bored or fatigued.

The researchers acknowledged that their study was small but their results suggest that workers might consider fatigue or boredom reducing alternatives. They noted also that some prior research has shown that boredom can sometimes be alleviated by engaging in activities that bring some degree of joy. They suggest that rather than mindlessly scrolling, they find ways to use their phones to bring them joy, such as by looking at pictures of loved ones.

Source: Medical Xpress

Journal information: Jonas Dora et al, Fatigue, boredom and objectively measured smartphone use at work, Royal Society Open Science (2021). DOI: 10.1098/rsos.201915

Categories : AgeingTags :

Study Confirms that Stress Turns Hair Grey – But It’s Reversible

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A new study for the first time provides quantitative evidence linking psychological stress to greying hair in people. 

Greying of hair, a phenomenon still poorly understood in humans, first starts in white individuals at 34, while black individuals only start greying around 44. While it may seem intuitive that stress can accelerate greying, the researchers were surprised to discover that hair colour can actually be restored when stress is eliminated, a finding that contrasts with a recent study in mice that suggested that stressed-induced grey hairs are permanent.

The study holds clues to understanding ageing beyond just confirming the old tale about stress and ageing, said the study’s senior author Martin Picard, PhD, associate professor of behavioral medicine (in psychiatry and neurology) at Columbia University Vagelos College of Physicians and Surgeons.  

“Understanding the mechanisms that allow ‘old’ grey hairs to return to their ‘young’ pigmented states could yield new clues about the malleability of human ageing in general and how it is influenced by stress,” Prof Picard said.

“Our data add to a growing body of evidence demonstrating that human ageing is not a linear, fixed biological process but may, at least in part, be halted or even temporarily reversed.”

Hair can help understand ageing

“Just as the rings in a tree trunk hold information about past decades in the life of a tree, our hair contains information about our biological history,” Picard said. “When hairs are still under the skin as follicles, they are subject to the influence of stress hormones and other things happening in our mind and body. Once hairs grow out of the scalp, they harden and permanently crystallise these exposures into a stable form.”

Though it has long been believed by people that psychological stress can increase grey hairs, it has remained a matter of scientific debate due to a lack of sensitive methods that can precisely correlate times of stress with hair pigmentation at a single-follicle level.

Splitting hairs to document hair pigmentation

Ayelet Rosenberg, first author on the study and a student in Picard’s laboratory, developed a new method for making high resolution images of tiny slices of human hairs to measure the extent of pigment loss — greying — in each of those slices. Each slice, about 1/20th of a millimetre wide, represents about an hour of hair growth.

“If you use your eyes to look at a hair, it will seem like it’s the same color throughout unless there is a major transition,” Picard says. “Under a high-resolution scanner, you see small, subtle variations in color, and that’s what we’re measuring.”

For the study 14 volunteers were asked to review their calendars and rate each week’s level of stress in a stress diary. Analysing individual hair samples, the researchers compared the results with each volunteer’s stress diary.

Right away, it was noticed that some grey hairs naturally regain their original color, which had never been quantitatively documented, Picard said.

When hairs were aligned with stress diaries, it revealed striking associations between stress and hair greying and, in some cases, a reversal of greying with the lifting of stress.

“There was one individual who went on vacation, and five hairs on that person’s head reverted back to dark during the vacation, synchronized in time,” Picard said.

Blame the mind-mitochondria connection

Measuring levels of different proteins in the hairs and how protein levels changed over the length of each hair, the researchers came up with a model showing that mitochondria were responsible for greying.

“We often hear that the mitochondria are the powerhouses of the cell, but that’s not the only role they play,” Picard said. “Mitochondria are actually like little antennas inside the cell that respond to a number of different signals, including psychological stress.”

The mitochondria connection between stress and hair colour is a different mechanism than found in a recent study of mice, where stress-induced greying was caused by an irreversible loss of stem cells in the hair follicle.

“Our data show that greying is reversible in people, which implicates a different mechanism,”  said co-author Ralf Paus, PhD, professor of dermatology at the University of Miami Miller School of Medicine. “Mice have very different hair follicle biology, and this may be an instance where findings in mice don’t translate well to people.”

Hair re-pigmentation possible only for some

Stress reduction is a good idea, but it won’t necessarily get rid of your grey hairs.

“Based on our mathematical modeling, we think hair needs to reach a threshold before it turns grey,” Picard said. “In middle age, when the hair is near that threshold because of biological age and other factors, stress will push it over the threshold and it transitions to grey.

“But we don’t think that reducing stress in a 70-year-old who’s been grey for years will darken their hair or increasing stress in a 10-year-old will be enough to tip their hair over the grey threshold.”

Source: Columbia University Irving Medical Center 

Journal information: Ayelet M. Rosenberg et al, Quantitative mapping of human hair greying and reversal in relation to life stress, eLife (2021). DOI: 10.7554/eLife.67437

Categories : Cardiovascular DiseaseTags :

Study Reveals Additional Pathway From Brain to Cardiovascular System

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Researchers at  University of Tsukuba in Japan have uncovered a previously unknown pathway from the brain to the cardiovascular system.

Though the cardiovascular system has a degree of autonomy to allow their independent functioning from the brain, the brain still has some control over it in order to respond to life-threatening situations. This control is exerted through the sympathetic and parasympathetic systems of the autonomic nervous system.

“From an evolutionary standpoint, the brain has had an incredibly important function in protecting the individual from predators,” says the lead author of the study Professor Tadachika Koganezawa. “But even in the absence of predators, our bodies react to stressful situations. In this study, we wanted to determine how the brain regulated the cardiovascular system via the autonomic nervous system.”

Located deep within the brain, the lateral habenula (LHb) has been known to elicit strong behavioural and cardiovascular responses to stressful events. But how it did so was still unclear. so to find out the researchers electrically stimulated the LHb in rats. This resulted in bradycardia and increased mean arterial pressure (MAP). The researchers then turned off the parasympathetic system by means of cutting the main parasympathetic nerve, the vagal nerve, or using a drug to antagonise it. 
Though this suppressed the LHb’s effect on the heart rate, the MAP was unchanged. Antagonising the sympathetic system had the opposite effect—decreasing the MAP but there was no effect on the heart rate.

To understand the mechanism by which the LHb elicits these cardiovascular responses, the researchers focused on the neurotransmitter serotonin, which plays an important role in the brain in modulating mood, cognition, and memory, among other functions.

While blocking all serotonin receptors significantly reduced the LHb’s effect on both the MAP and heart rate, the researchers found that specific subtypes of serotonin receptors were particularly involved in the process.

“These are striking results that show how the lateral habenula controls the cardiovascular system,” said study author Professor Masayuki Matsumoto , University of Tsukuba. “Our results demonstrate the mechanism of a neural circuit that plays an important role in stress-induced behavioral responses.”

Source: News-Medical.Net

Journal information: Doan, T. H., et al. (2021) Lateral Habenula Regulates Cardiovascular Autonomic Responses via the Serotonergic System in Rats. Frontiers in Neuroscience. doi.org/10.3389/fnins.2021.655617.

Categories : UncategorizedTags :

New Earwax Cortisol Test Lauded for Measuring Stress Levels

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A new way to gauge cortisol levels has been tested that involves testing a sample of earwax obtained using a cotton bud with a simple brake to prevent it penetrating too far into the ear.

Although blood, urine or saliva can be tested, they only measure short-term levels of cortisol, which can be highly variable, even from the stress of the sample being taken. Earwax samples can provide estimates of stable long-term levels of cortisol.

Lead researcher Dr Andres Herane-Vives, of University College London’s Institute of Cognitive Neuroscience said, “Cortisol sampling is notoriously difficult, as levels of the hormone can fluctuate, so a sample might not be an accurate reflection of a person’s chronic cortisol levels. Moreover, sampling methods themselves can induce stress and influence the results.

“But cortisol levels in earwax appear to be more stable, and with our new device, it’s easy to take a sample and get it tested quickly, cheaply and effectively.”

This new earwax cortisol test, which proved faster and yielded more cortisol than one taking samples from hair, has the potential to be very cheap and can be conducted at home. The technology could even be adapted to measure other biomarkers, and potentially test for COVID.

Source: The Guardian