Exercise May Reduce Sleep Apnea and Improve Brain Health

Laura Williamson wrote . . . . . . . . .

Exercise may help reduce symptoms of a common sleep disorder and improve brain function, a small study finds.

Exercise training could be a useful supplemental treatment for people with moderate to severe obstructive sleep apnea, the research showed. The condition is characterized by loud snoring and disrupted breathing and can raise the risk for heart disease, stroke and cognitive decline. It is typically treated with continuous positive airway pressure, or CPAP, a machine that pushes air through a mask into the airway to keep it open while a person sleeps.

“Exercise training appears to be an attractive and adjunctive (add-on) non-pharmacological treatment,” said lead investigator Linda Massako Ueno-Pardi, an associate professor at the School of Arts, Science and Humanities at the University of São Paulo in Brazil. She also is a research collaborator at the university’s Heart Institute and Institute of Psychiatry, Faculty of Medicine.

Estimates show obstructive sleep apnea affects roughly 9% to 38% of U.S. adults, though many cases are thought to be undiagnosed. It is more common in men than women and becomes more prevalent as people age.

According to a scientific statement by the American Heart Association published in June, between 40% and 80% of people with cardiovascular disease have sleep apnea.

The condition often is associated with obesity, which can narrow the airway at the back of the throat, making it harder to breathe while lying down. Cigarette smoking, family history, nasal congestion, back sleeping, drinking alcohol, having a thicker neck or narrow throat and some hormone abnormalities also can contribute to the condition. Some medical conditions, such as Type 2 diabetes, also raise the risk for sleep apnea.

Previous studies have shown people with sleep apnea experience a decrease in brain glucose metabolism, or the brain’s ability to upload and properly use glucose, its main source of fuel. This can impair cognitive function. Ueno-Pardi and her team explored whether exercise could help correct that.

The new work builds upon a small 2019 study in the journal Brain Plasticity that concluded increased aerobic activity improved brain glucose metabolism and executive function in older, middle-aged adults at risk for Alzheimer’s disease.

The new research included 47 Brazilian adults with moderate to severe obstructive sleep apnea. Half took part in 60 minutes of supervised exercise three times per week for six months. The other half did not. The supervised exercise included five minutes of warming up; 25-40 minutes riding a stationary bicycle, 10 minutes of muscle strengthening and five minutes of cooling down.

Participants in both groups were given a series of tests to measure exercise capacity, brain glucose metabolism and cognitive function, including attention and executive function – the ability to plan and carry out tasks. Researchers also measured the severity of obstructive sleep apnea symptoms, such as disruptions to breathing and reductions in the body’s oxygen levels, or hypoxia, which has been shown to impact attention and executive function skills.

At the end of six months, those in the exercise group showed an increased capacity for exercise; improvements in the brain’s ability to use glucose; reductions in sleep apnea symptoms; and a boost in cognitive function, including a 32% improvement in attention and executive function. Those who did not exercise experienced no changes except a decline in brain glucose metabolism.

The findings, reported this week at the AHA’s Hypertension Scientific Sessions virtual conference, are considered preliminary until published in a peer-reviewed journal.

The research makes a good case as to why exercise should be added to the treatment strategy for sleep apnea, said Michael Grandner, director of the Sleep and Health Research Program and associate professor of psychiatry at the University of Arizona College of Medicine in Tucson. He was not involved in the study.

The findings are important because they show exercise could benefit brain health in people with sleep disorders, he said.

“Our current treatments largely involve pushing air down people’s airways, which is great, and it works. But it is kind of a blunt instrument. Exercise training is one option that could add benefit and maybe even be curative. This is especially important with a disease where our gold standard treatment is not curative.”

CPAP machines do little to address obesity, the largest cause of obstructive sleep apnea. Exercise training may be effective in reducing the excess fat around the airways that makes it harder for people to breathe at night, Grandner said.

That’s one of the outcomes Ueno-Pardi believes happened in her study. While she and her team didn’t measure weight loss or muscle tone, they did measure percentage of body fat and found a “significant reduction” in the exercise group, she said. The exercise may have improved sleep apnea severity by decreasing body fat, especially around the airways.

“There’s a lot of research out there that weight loss is a really powerful strategy for treating sleep apnea,” Grandner said.

Source: American Heart Association

Swimming Gives Your Brain a Boost – But Scientists Don’t Know Yet Why It’s Better than Other Aerobic Activities

Seena Mathew wrote . . . . . . . . .

It’s no secret that aerobic exercise can help stave off some of the ravages of aging. But a growing body of research suggests that swimming might provide a unique boost to brain health.

Regular swimming has been shown to improve memory, cognitive function, immune response and mood. Swimming may also help repair damage from stress and forge new neural connections in the brain.

But scientists are still trying to unravel how and why swimming, in particular, produces these brain-enhancing effects.

As a neurobiologist trained in brain physiology, a fitness enthusiast and a mom, I spend hours at the local pool during the summer. It’s not unusual to see children gleefully splashing and swimming while their parents sunbathe at a distance – and I’ve been one of those parents observing from the poolside plenty of times. But if more adults recognized the cognitive and mental health benefits of swimming, they might be more inclined to jump in the pool alongside their kids.

Until the 1960s, scientists believed that the number of neurons and synaptic connections in the human brain were finite and that, once damaged, these brain cells could not be replaced. But that idea was debunked as researchers began to see ample evidence for the birth of neurons, or neurogenesis, in adult brains of humans and other animals.

Now, there is clear evidence that aerobic exercise can contribute to neurogenesis and play a key role in helping to reverse or repair damage to neurons and their connections in both mammals and fish.

Research shows that one of the key ways these changes occur in response to exercise is through increased levels of a protein called brain-derived neurotrophic factor. The neural plasticity, or ability of the brain to change, that this protein stimulates has been shown to boost cognitive function, including learning and memory.

Studies in people have found a strong relationship between concentrations of brain-derived neurotrophic factor circulating in the brain and an increase in the size of the hippocampus, the brain region responsible for learning and memory. Increased levels of brain-derived neurotrophic factor have also been shown to sharpen cognitive performance and to help reduce anxiety and depression. In contrast, researchers have observed mood disorders in patients with lower concentrations of brain-derived neurotrophic factor.

Aerobic exercise also promotes the release of specific chemical messengers called neurotransmitters. One of these is serotonin, which – when present at increased levels – is known to reduce depression and anxiety and improve mood.

In studies in fish, scientists have observed changes in genes responsible for increasing brain-derived neurotrophic factor levels as well as enhanced development of the dendritic spines – protrusions on the dendrites, or elongated portions of nerve cells – after eight weeks of exercise compared with controls. This complements studies in mammals where brain-derived neurotrophic factor is known to increase neuronal spine density. These changes have been shown to contribute to improved memory, mood and enhanced cognition in mammals. The greater spine density helps neurons build new connections and send more signals to other nerve cells. With the repetition of signals, connections can become stronger.

But what’s special about swimming?

Researchers don’t yet know what swimming’s secret sauce might be. But they’re getting closer to understanding it.

Swimming has long been recognized for its cardiovascular benefits. Because swimming involves all of the major muscle groups, the heart has to work hard, which increases blood flow throughout the body. This leads to the creation of new blood vessels, a process called angiogenesis. The greater blood flow can also lead to a large release of endorphins – hormones that act as a natural pain reducer throughout the body. This surge brings about the sense of euphoria that often follows exercise.

Research in people suggest a clear cognitive benefit from swimming across all ages. For instance, in one study looking at the impact of swimming on mental acuity in the elderly, researchers concluded that swimmers had improved mental speed and attention compared with nonswimmers. However, this study is limited in its research design, since participants were not randomized and thus those who were swimmers prior to the study may have had an unfair edge.

Another study compared cognition between land-based athletes and swimmers in the young adult age range. While water immersion itself did not make a difference, the researchers found that 20 minutes of moderate-intensity breaststroke swimming improved cognitive function in both groups.

Kids get a boost from swimming too

The brain-enhancing benefits from swimming appear to also boost learning in children.

Another research group recently looked at the link between physical activity and how children learn new vocabulary words. Researchers taught children age 6-12 the names of unfamiliar objects. Then they tested their accuracy at recognizing those words after doing three activities: coloring (resting activity), swimming (aerobic activity) and a CrossFit-like exercise (anaerobic activity) for three minutes.

They found that children’s accuracy was much higher for words learned following swimming compared with coloring and CrossFit, which resulted in the same level of recall. This shows a clear cognitive benefit from swimming versus anaerobic exercise, though the study does not compare swimming with other aerobic exercises. These findings imply that swimming for even short periods of time is highly beneficial to young, developing brains.

The details of the time or laps required, the style of swim and what cognitive adaptations and pathways are activated by swimming are still being worked out. But neuroscientists are getting much closer to putting all the clues together.

For centuries, people have been in search of a fountain of youth. Swimming just might be the closest we can get.

Source: Conversation

Exercise Boosts Blood Flow to Brain, Keeping it Sharp

Regular aerobic exercise increases blood flow to the brain, which may help slow mental decline in older adults, a new, small study suggests.

Researchers from University of Texas Southwestern Medical Center looked at 70 men and women diagnosed with mild cognitive impairment (MCI). This means there are slight changes to the brain that affect memory, decision-making or reasoning skills. In many cases, MCI progresses to Alzheimer’s disease and other types of dementia.

“This [study] is part of a growing body of evidence linking exercise with brain health,” study leader Rong Zhang, a professor of neurology, said in a UT Southwestern news release. “We’ve shown for the first time in a randomized trial in these older adults that exercise gets more blood flowing to your brain.”

The study participants were ages 55-80. They were randomly assigned to do either a moderate aerobic exercise program or a stretching program for one year. The aerobic exercise program involved three to five exercise sessions a week, each with 30-40 minutes of moderate exercise such as a brisk walk.

Forty-eight volunteers finished the year-long training and returned for follow-up tests. By that time, blood flow to the brain had increased among the 19 participants in the aerobic exercise program, but not among the 29 in the stretching program.

The aerobic group also showed decreased stiffness of blood vessels in their neck. The researchers did not detect changes in these measurements among people who followed the stretching program.

The study didn’t find any significant changes in memory or thinking, but that may be because of the small size or short length of the trial, according to the researchers. They noted that changes to blood flow to the brain could precede mental decline.

They’re now conducting a larger two-year study to further examine the link between exercise and mental decline.

As many as one-fifth of people 65 and older have some degree of mild cognitive impairment. Previous research has shown that lower-than-normal levels of blood flow to the brain, and stiffer blood vessels leading to the brain, are associated with MCI and dementia.

“There is still a lot we don’t know about the effects of exercise on cognitive decline later in life,” study co-author C. Munro Cullum, a professor of clinical psychology, said in the release. “MCI and dementia are likely to be influenced by a complex interplay of many factors, and we think that, at least for some people, exercise is one of those factors.”

The results were published online in the Journal of Alzheimer’s Disease.

Source: HealthDay

Primary Care Doctors Can Help Preserve Brain Health

Primary care doctors can play an important role in helping to preserve brain health by encouraging healthy behaviors and addressing risk factors associated with cognitive decline, according to a new scientific report.

The American Heart Association statement published Monday in the journal Stroke outlines seven lifestyle targets and six risk factors for brain health that primary care doctors should address in adults of all ages. The statement also has been endorsed by the American Academy of Neurology as an educational tool for neurologists.

As the nation ages, preserving brain health has become a growing concern. Mild cognitive impairment affects an estimated 1 in 5 Americans age 65 and older; 1 in 7 has dementia – a number expected to triple by 2050.

“Primary care is the right home for practice-based efforts to prevent or postpone cognitive decline,” Ronald Lazar, chair of the scientific statement writing group, said in a news release. Lazar directs the Evelyn F. McKnight Brain Institute at the University of Alabama at Birmingham.

“Prevention doesn’t start in older age; it exists along the health care continuum from pediatrics to adulthood,” he said. “The evidence in this statement demonstrates that early attention to these factors improves later life outcomes.”

The statement asks primary care doctors to integrate brain health into their treatment of adults guided by the AHA’s Life’s Simple 7, a collection of lifestyle targets shown to help achieve ideal heart and brain health. These include managing blood pressure, cholesterol and blood sugar levels; increasing physical activity; eating a healthy diet; losing weight; and not smoking.

The statement also asks them to assess their patients’ risk factors for cognitive health, including depression, social isolation, excessive alcohol use, sleep disorders, lower education levels and hearing loss.

“Scientists are learning more about how to prevent cognitive decline before changes to the brain have begun,” Lazar, a professor of neurology and neurobiology, said. “We have compiled the latest research and found Life’s Simple 7 plus other factors like sleep, mental health and education are a more comprehensive lifestyle strategy that optimizes brain health in addition to cardiovascular health.”

Dr. Deborah Levine, one of the statement’s co-authors, said it is never too soon to target risk factors for ideal heart and brain health. It’s also never too late.

“For example, lower blood pressure levels reduce the risk of cognitive impairment and dementia in older adults,” she said. “In adults of all ages, the metrics in Life’s Simple 7 prevent stroke, and stroke increases the risk of dementia by more than twofold.”

Additional risk factors can help physicians identify which patients may need special attention, said Levine, an associate professor of medicine at the University of Michigan Medical School in Ann Arbor.

For example, “Primary care doctors can help their patients reduce dementia risk by identifying and aggressively treating vascular risk factors like high blood pressure. Black and Hispanic individuals, women and individuals with lower educational levels appear at higher risk for dementia, so these high-risk groups are a top priority,” Levine said.

According to the statement, recent research shows high blood pressure, diabetes and smoking in adulthood and midlife increase the odds of cognitive decline in middle age. And they accelerate cognitive decline in older age.

“Many people think of high blood pressure, Type 2 diabetes and other risk factors as affecting only heart health, yet these very same risk factors affect our brain health,” Lazar said. “Patients might be more likely to pay attention to the importance of addressing modifiable risk factors if they understood the links.”

The statement defines brain health using the term cognition, which includes memory, thinking, reasoning, communication and problem-solving.

Together, these functions enable people to navigate the everyday world, according to the report. The ability to think, solve problems, remember, perceive and communicate are crucial to successful living; their loss can lead to helplessness and dependency.

“Studies have shown that these domains are impacted by factors that are within our control to change,” Lazar said. “Prevention and mitigation are important, because once people have impaired cognition, the current treatment options are very limited.”

Source: American Heart Association

Prediabetes May be Linked to Worse Brain Health

People with prediabetes, whose blood sugar levels are higher than normal, may have an increased risk of cognitive decline and vascular dementia, according to a new study led by UCL researchers.

For the study, published in the journal Diabetes, Obesity and Metabolism, researchers analysed data from the UK Biobank of 500,000 people aged 58 years on average, and found that people with higher than normal blood sugar levels were 42% more likely to experience cognitive decline over an average of four years, and were 54% more likely to develop vascular dementia over an average of eight years (although absolute rates of both cognitive decline and dementia were low).

The associations remained true after other influential factors had been taken into account – including age, deprivation, smoking, BMI and whether or not participants had cardiovascular disease.

People with prediabetes have blood sugar levels that are higher than usual, but not high enough to be diagnosed with type 2 diabetes. It means they are more at risk of developing diabetes. There are an estimated five to seven million people* with prediabetes in the UK.

Lead author Dr Victoria Garfield (UCL Institute of Cardiovascular Science and the UCL MRC Unit for Lifelong Health & Ageing) said: “Our research shows a possible link between higher blood sugar levels – a state often described as ‘prediabetes’ – and higher risks of cognitive decline and vascular dementia. As an observational study, it cannot prove higher blood sugar levels cause worsening brain health. However, we believe there is a potential connection that needs to be investigated further.

“Previous research has found a link between poorer cognitive outcomes and diabetes but our study is the first to investigate how having blood sugar levels that are relatively high – but do not yet constitute diabetes – may affect our brain health.”

In the study, researchers investigated how different blood sugar levels, or glycaemic states, were associated with performance in cognitive tests over time, dementia diagnoses, and brain structure measured by MRI scans of the brain. Each of these measures were limited to smaller subsets of the Biobank sample (for instance, only 18,809 participants had follow-up cognitive tests).

At recruitment all of the UK Biobank participants underwent an HbA1c test, which determines average blood sugar levels over the past two to three months. Participants were divided into five groups on the basis of the results – “low-normal” level of blood sugar, normoglycaemia (having a normal concentration of sugar in the blood), prediabetes, undiagnosed diabetes and diabetes. A result between 42-48 mmol/mol (6.0-6.5%) was classified as prediabetes.

The researchers used data from repeated assessments of visual memory to determine whether participants had cognitive decline or not. Though absolute rates of cognitive decline were low, people with prediabetes and diabetes had a similarly higher likelihood of cognitive decline – 42% and 39% respectively.

Looking at dementia diagnoses, researchers found that prediabetes was associated with a higher likelihood of vascular dementia, a common form of dementia caused by reduced blood flow to the brain, but not Alzheimer’s disease. People with diabetes, meanwhile, were three times more likely to develop vascular dementia than people whose blood sugar levels were classified as normal, and more likely to develop Alzheimer’s disease.

Senior author Professor Nishi Chaturvedi (UCL MRC Unit for Lifelong Health & Ageing) said: “In this relatively young age group, the risks of cognitive decline and of dementia are very low; the excess risks we observe in relation to elevated blood sugar only modestly increase the absolute rates of ill health. Seeing whether these effects persist as people get older, and where absolute rates of disease get higher, will be important.

“Our findings also need to be replicated using other datasets. If they are confirmed, they open up questions about the potential benefits of screening for diabetes in the general population and whether we should be intervening earlier.”

Among 35,418 participants of the UK Biobank study who underwent MRI brain scans, researchers found that prediabetes was associated somewhat with a smaller hippocampus and more strongly associated with having lesions on the brain (white matter hyperintensities, WMHs) – both associated with age-related cognitive impairment.

The researchers said that some of these differences could be explained by elevated blood pressure, as those participants taking antihypertensive medication were likely to have more WMHs and smaller hippocampal volume. Rather than the treatment having an adverse effect on the brain, the researchers said use of such medication might be an indicator of earlier untreated high blood pressure.

People with prediabetes can reduce their risk of developing type 2 diabetes by eating a healthy, balanced diet, being more active, and staying at a healthy weight.

Source: University College London