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 Survival for People With Implanted Defibrillators

Just small amounts of exercise can benefit people with implanted heart defibrillators, new research shows.

An implantable cardioverter defibrillator (ICD) is a battery-powered device placed under the skin to detect abnormal heart rhythms and deliver an electric shock to restore a normal heartbeat.

The new study found that even slight increases in physical activity reduced the risk of hospitalization and early death after patients got an ICD. And that was true even if their fitness boost wasn’t from a formal rehabilitation program, according to findings published in the journal Circulation: Cardiovascular Quality and Outcomes.

“Cardiac rehabilitation programs offer patients a safe environment to increase physical activity after ICD implantation,” said study author Dr. Brett Atwater, director of electrophysiology at the Inova Heart and Vascular Institute in Fairfax, Va.

“Evidence has also shown cardiac rehab lessens the risk of additional hospitalization and death, but cardiac rehabilitation programs are underutilized, especially among women, the elderly, people from diverse racial and ethnic groups and those living in rural areas,” he said in a journal news release.

Atwater and his team examined data on nearly 42,000 Medicare patients (average age: 75) who got ICDs between 2014 and 2016.

Of those, 3% took part in a heart rehab program. During rehab, their physical activity rose by nearly 10 minutes a daily, compared to a minute-a-day drop off among patients not in rehab.

Those in a rehab program were 24% less likely to die within three years of getting their ICD than patients who were not in rehab.

The study also linked every 10 minutes of increased daily activity to a 1.1% reduction in death from all causes during that time span — whether patients were in a formal rehab program or not.

“Our study examined whether physical activity outside of a formal cardiac rehabilitation program could yield similar benefits, and we found it did,” Atwater said. “This suggests that additional options like home-based cardiac rehabilitation might help more patients realize the health benefits of increased physical activity.”

Source: HealthDay

Study: Want to Avoid Running Overuse Injuries? Don’t Lean Forward So Much

The ubiquitous overuse injuries that nag runners may stem from an unlikely culprit: how far you lean forward.

Trunk flexion, the angle at which a runner bends forward from the hip, can range wildly–runners have self-reported angles of approximately -2 degrees to upward of 25. A new study from the University of Colorado Denver (CU Denver) found that greater trunk flexion has significant impact on stride length, joint movements, and ground reaction forces. How you lean may be one of the contributors to your knee pain, medial tibial stress syndrome, or back pain.

“This was a pet peeve turned into a study,” said Anna Warrener, PhD, lead author and assistant professor of anthropology at CU Denver. Warrener worked on the initial research during her postdoc fellowship with Daniel Liberman, PhD, in the Department of Human Evolutionary Biology at Harvard University. “When [Lieberman] was out preparing for his marathons, he noticed other people leaning too far forward as they ran, which had so many implications for their lower limbs. Our study was built to find out what they were.”

The study was published in Human Movement Science.

A New Angle on Overuse Injuries

The head, arms and trunk constitute roughly 68% of total body mass. Small changes in trunk flexion have the potential to substantially alter lower-limb kinematics and ground reaction forces (GRF) during running.

To study the downstream effects, Warrener and her team recruited 23 injury-free, recreational runners between the ages of 18 and 23. They recorded each participant running 15-second trials at their self-selected trunk position and three others: a 10-, 20-, and a 30-degree angle of flexion. But to make the study work, they had to first figure out how to get each runner to bend at the right slant.

“We had to create a way in which we could reasonably force someone into a forward lean that didn’t make them so uncomfortable that they changed everything about their gait,” said Warrener. The team hung a lightweight, plastic dowel from the ceiling just above the runners’ heads, moving it up or down, depending on the angle needed.

Contrary to the team’s original hypothesis, the average stride length decreased 13 cm and stride frequency increased from 86.3 strides/min to 92.8 strides/min. Overstride relative to the hip increased 28%.

“The relationship between strike frequency and stride length surprised us,” said Warrener. “We thought that the more you lean forward, your leg would need to extend further to keep your body mass from falling outside the support aera. As a result, overstride and stride frequency would go up. The inverse was true. Stride length got shorter and stride rate increased.”

Warrener believes this may be due to a decrease in the aerial phase (if they’re not getting as much air time, runners will take shorter steps), which means leg swings quickened as a result of reduced forward movement.

“The act of swinging your leg is really expensive as you’re running,” said Warrener. “Swinging it faster as you lean forward may mean a higher locomotor cost.”

Compared to the participants’ natural trunk flexion, increased angles led to a more flexed hip and bent knee joint. A bigger lean also changed the runners’ foot and lower limb position, leading to an increased impact of GRF on the body (rate of loading by 29%; vertical ground reaction force impact transients by 20%).

The combination of trunk flexion angle, foot and leg placement, and GRF variables, shows that excessive trunk flexion could be one cause of injurious running form and, according to Warrener, is key for understanding how diverse running forms optimize economy and performance.

“The big picture takeaway is that running is not all about what is happening from the trunk down–it’s a whole-body experience,” said Warrener. “Researchers should think about the downstream effects of trunk flexion when studying running biomechanics.”

Source: EurekAlert!

Sleep, Exercise & Your Odds for a Long, Healthy Life

Denise Mann wrote . . . . . . . . .

Poor quality sleep can shave years off your life, and these effects may be magnified if you don’t get enough physical activity.

That’s the bad news. The good news is that getting more exercise may help counter some of the health risks known to accompany poor quality sleep, new research shows.

Folks who scored low in both sleep and exercise categories were 57% more likely to die from heart disease, stroke and cancer over more than a decade of follow-up when compared with those who reported getting better sleep and more exercise.

“Physical inactivity seems to amplify the health risks of poor sleep patterns in a synergistic way,” said study co-author Emmanuel Stamatakis.

“The mortality risk from physical inactivity and poor sleep combined is larger than the sum of the separate risks of poor sleep and physical inactivity,” added Stamatakis, a professor of physical activity, lifestyle and population health at the University of Sydney in Australia.

But getting at least 150 minutes of moderate or 75 minutes of vigorous exercise each week seems to dampen these effects, he said.

The study wasn’t designed to say how, or even if, poor sleep and lack of exercise work together, but researchers do have their theories.

Many sleep problems, such as short sleep or insomnia, cause hormonal and metabolic dysfunction and inflammation, and stimulate the sympathetic nervous system, Stamatakis explained. When the sympathetic nervous system is activated, it triggers the release of stress hormones that can increase heart rate and blood pressure, which can raise your risk for heart disease over time.

Physical activity works on the same pathways but in the opposite direction, Stamatakis said. “A possible explanation is that regular activity helps neutralize some of these consequences of poor sleep,” he noted.

For the study, the researchers analyzed information from more than 380,000 middle-aged men and women who took part in the large-scale U.K. Biobank study.

People were given a sleep score of 0 to 5 based on several factors, including whether they typically got seven to eight hours of sleep a night, had insomnia regularly, snored, felt tired during the day, or were a “night owl” or “morning lark.”

The sleep score was combined with a high, medium or low physical activity score, and people were categorized based on different combinations of sleep and exercise scores.

The lower the sleep score, the higher the risks of death from any cause during the 11-year follow-up. Exercise, however, blunted some of these effects.

“For someone who moves very little in general, I would advise them to introduce small amounts of physical activity of about 10-15 minutes per day that can comfortably fit into their daily routine and work towards 25-30 minutes per day over time,” Stamatakis said.

There will be spillover benefits on your sleep, too. “Physical activity improves sleep quality so they will enjoy the direct benefits of physical activity/exercise and may receive some help with their sleep problems,” Stamatakis said.

The study had its share of limitations. Folks only provided information on their sleep and physical activity at one point in time so researchers can’t know whether these habits changed with time.

The findings appear in the British Journal of Sports Medicine.

“If you are having trouble sleeping, but still manage to exercise regularly, you are in a better place than someone who is not exercising and having sleep problems,” said Dr. Martha Gulati, editor-in-chief of CardioSmart.org, the American College of Cardiology’s educational site for patients.

“This is the first study I have seen that looked at how sleep and exercise interact,” said Gulati, who has no ties to the new research. “There appears to be a synergy between the two, but more research is needed to tease out exactly how sleep and exercise work together to affect health.”

If you are not sleeping enough, you may be too tired to exercise, she said. It’s also possible that an underlying medical condition may be affecting your sleep.

Source: HealthDay

Even on ‘Down’ Days, Music a Motivator for Runners

The key to pushing through mental fatigue while running might be adding some earbuds to your workout gear.

U.K. researchers worked with 18 fitness enthusiasts to determine the impact of music on running performance. They found that running to self-selected tunes improved runners’ performance when mentally fatigued during two separate tests.

“Mental fatigue is a common occurrence for many of us, and can negatively impact many of our day-to-day activities, including exercise,” said study author Shaun Phillips, of the University of Edinburgh’s Moray House School of Education and Sport.

The first test looked at the effects on interval running capacity — alternating between high-intensity running and lower-intensity jogging — on nine physically active exercisers. The second test involved a 3-mile time trial with nine runners.

The groups completed a 30-minute computer-based cognitive test that put them in a mentally fatigued state before completing high-intensity exercise. Researchers tested the runners both with and without self-selected motivational music after assisting the participants with a pre-test questionnaire that asked them to rate the rhythm, style, melody, tempo, sound and beat of the music.

Songs included Survivor’s “Eye of the Tiger,” Kanye West’s “Power” and Queens of the Strong Age’s “No One Knows.”

The researchers found the interval running capacity among the mentally fatigued fitness enthusiasts was greater with music compared to without music. It was the same as when the participants were not mentally fatigued.

The 3-mile time trial performances also showed small improvements with self-selected music versus no music.

The positive effects of music could potentially be due to altered perception of effort when listening to tunes, researchers said. This presents an opportunity for further study on how listening to music while running affects other groups of people, as well as in different exercise challenges. Research is ongoing at the University of Edinburgh.

“The findings indicate that listening to self-selected motivational music may be a useful strategy to help active people improve their endurance running capacity and performance when mentally fatigued,” Phillips said in a university news release. “This positive impact of self-selected music could help people to better maintain the quality and beneficial impact of their exercise sessions.”

The study was published online recently in the Journal of Human Sport and Exercise.

Source: HealthDay