Tuesday, April 25, 2017

Exercise boosts brain power in over 50s, concludes latest meta-analysis

The latest review concludes that exercise can, in fact, benefit the brains of older adults.

Over the years, there has been much research on the potential cognitive benefits of exercise on mental performance in older adults. Overall, results have been inconclusive, but a new review takes a fresh look at the data.

As we age, our cognitive prowess tends to take a hit. Finding a way to halt or reduce this decline would make a huge difference to billions of lives.

One potential intervention is exercise, and many researchers have attempted to prove whether or not it can stave off age-related mental decline and neurodegenerative conditions.

Early research and meta-analyses demonstrated strong, positive results. Over recent years, however, published reviews on the topic have not reported such strong effects.

A fresh look at aging and the brain
According to the authors of the current paper, recently published reviews and meta-analyses have been inconclusive due to their restrictive inclusion criteria. For instance, some focused on just one type of exercise, while others limited their literature search to a narrow date range. The latest review is published this week in the British Journal of Sports Medicine.

The new analysis casts its net wide, looking at aerobic exercise, resistance training (such as weights), multicomponent exercise (including both resistance and aerobic training), tai chi, and yoga.

To fully assess the impact of these interventions, they looked at a raft of cognitive parameters. These include:
1. Brain capacity - global cognition
2. Attention - sustained alertness, including speed of information processing
3. Executive function - including goal-oriented behaviors
4. Memory - storage and retrieval
5.Working memory - the part of short-term memory that deals with immediate conscious perceptual and language processing

The team's analysis showed that exercise improved the brain power of people aged 50 and older, regardless of their current brain health.

Prescribing exercise
The results suggested that aerobic exercise enhanced cognitive abilities, while resistance training had a positive influence on executive function, memory, and working memory. According to the researchers, the results were strong enough to recommend prescribing both exercise types to bolster brain health in over 50s.

The next question asks how much exercise is needed. According to the analysis, a session of moderate to vigorous intensity lasting between 45 and 60 minutes was beneficial to brain health. In fact, any frequency had positive effects. The authors conclude that:

"The findings suggest that an exercise program with components of both aerobic and resistance type training, of at least moderate intensity and at least 45 minutes per session, on as many days of the week as possible, is beneficial to cognitive function in adults aged over 50 years."

Interestingly, tai chi was also found to improve cognitive capabilities. This is important because, as a low-impact exercise, it can be carried out by people who could not physically cope with more intense regimes. However, the authors point out that this conclusion was based on only a small number of studies, making the finding less robust.

How exercise might reduce cognitive decline
Although there is a great deal of debate on this topic, scientists believe that there are a number of ways that exercise could help to stave off dementia and other degenerative neurological conditions.

According to the authors of the study, these include the promotion of neurogenesis (growth of new nervous tissue), angiogenesis (growth of new blood vessels), synaptic plasticity (the ability of synapses to strengthen or weaken over time), decreased pro-inflammatory processes, and reduced cellular damage due to oxidative stress.

Although the results will be widely heralded as positive, the authors note certain limitations to the study. For example, the analysis was limited to studies that looked at supervised exercise, and only those that were published in the English language.

If physical exercise really can stave off cognitive decline, it will benefit the population at large. This type of intervention can, of course, be cost effective or even free. If it has large-scale benefits, it could be a simple way of improving the lives of millions of older adults.

Even though the cognitive benefits may be small, the physical benefits of exercise are well established - so it is a win-win situation either way.

Working memory training combined with brain stimulation can improve performance, research shows

Your Saturday Salsa club or Introductory Italian class might be even better for you than you thought.

According to Sandia National Laboratories cognitive scientist Mike Trumbo, learning a language or an instrument or going dancing is the best way to keep your brain keen despite the ravages of time. Not only do you enhance your cognition but you also learn a skill and have fun..

Several commercial enterprises have claimed you can get cognitive benefits from brain training games intended to enhance working memory. Working memory is the amount of information you can hold and manipulate in your mind at one time, said cognitive scientist Laura Matzen. However, a burgeoning body of research shows working memory training games don't provide the benefits claimed. A study by Trumbo, Matzen and six colleagues published in Memory and Cognition shows evidence that working memory training actually impairs other kinds of memory..

On the other hand, studies have shown that learning another language can help school-age children do better in math and can delay the onset of dementia in older adults. Also going dancing regularly is the best protection against dementia compared to 16 different leisure activities, such as doing crossword puzzles and bicycling. Playing board games and practicing a musical instrument are the next best activities for keeping the mind sharp. Dancing is probably so effective because it combines cognitive exertion, physical exercise and social interaction, said Trumbo..

New research from Sandia published in Neuropsychologia shows that working memory training combined with a kind of noninvasive brain stimulation can lead to cognitive improvement under certain conditions. Improving working memory or cognitive strategies could be very valuable for training people faster and more efficiently..

"The idea for why brain stimulation might work when training falls short is because you're directly influencing brain plasticity in the regions that are relevant to working memory task performance. If you're improving connectivity in a brain region involved in working memory, then you should get transfer to other tasks to the extent that they rely on that same brain region," said Trumbo. "Whereas when you're having people do tasks in the absence of brain stimulation, it's not clear if you're getting this general improvement in working memory brain areas. You might be getting very selective, task kind of improvements.".

Matzen cautioned that research using transcranial direct current stimulation (tDCS) to improve cognitive performance is relatively new, and the field has produced mixed results. More research is needed to understand how best to use this technology..

Neurons that fire together wire together
Using more than 70 volunteers divided into six groups, the researchers used different combinations of working memory training with transcranial direct current stimulation. Then they assessed the volunteers' performance on working memory tests and a test of problem-solving ability..

Using electrodes placed on the scalp and powered by a 9-volt battery, a tDCS unit delivers weak constant current through the skull to the brain tissue below. According to Trumbo, most people feel some mild tingling, itching or heat under the electrode for the first few minutes. There are well-established safety guidelines for tDCS research, ensuring that the procedure is safe and comfortable for participants and this research was approved by Sandia's Human Studies Board and the University of New Mexico's Institutional Review Board. There are commercial tDCS devices already on the market..

Researchers think tDCS makes neurons a little bit more likely to fire, which can help speed up the formation of neuronal connections and thus learning, said Matzen. Though the exact mechanisms aren't well understood, its potential is. According to studies, tDCS can help volunteers remember people's names, is better than caffeine at keeping Air Force personnel awake and may even help fight depression. Brain stimulation and brain training: better together? In the Sandia-led study, the volunteers played verbal or spatial memory training games for 30 minutes while receiving stimulation to the left or right forehead. That part of the brain is called the dorsolateral prefrontal cortex and is involved in working memory and reasoning. Since the right hemisphere is involved in spatial tasks and the left hemisphere is involved in verbal tasks, the researchers thought volunteers who received stimulation on the right side while training on spatial tasks would improve on spatial tests and those who received stimulation on the left side while training on verbal tasks would improve on verbal tests...

The verbal task involved remembering if a letter had appeared three letters back in a string of letters, for instance A-C-B-A-D. The spatial task was similar but involved remembering the sequence that blocks appear in a grid...

As expected, the spatial/right group got better at the spatial test but not verbal or reasoning tests. The spatial/left group performed about the same as the volunteers that received mock stimulation. The verbal/left group got better at the verbal test but not spatial or reasoning tests...

However, the results from the verbal/right group were surprising, said Trumbo. This group got better at the trained task -- remembering strings of letters -- as well as the closely related task -- remembering the sequence of boxes in a grid. They also improved on a reasoning test. The sample size was small, with only 12 volunteers, but the improvements were statistically significant, said Matzen...

One explanation Trumbo offered is that the right dorsolateral prefrontal cortex is particularly involved in strategy use during tasks. By stimulating the right side during the verbal task, the volunteers might get better at using a strategy. The tDCS improves the connections of these neurons, which leads to enhanced ability to use this strategy, even on other tasks...

He added, "We did not explicitly collect data related to strategy use, so it is kind of an open question. I'd really like to do some follow-up work."..

If tDCS can reliably enhance working memory or cognitive strategies, it could be very useful for training people faster and more efficiently. Matzen said, "This could benefit many mission areas at Sandia where people must learn complex tools and systems. ..

Reducing training time and improving cognitive performance would have substantial benefits to overall system performance."

Health benefits of Salmon

Salmon is both a freshwater and a saltwater fish. It is anadromous, meaning that it is born in freshwater, travels and lives in salt water and returns to freshwater to spawn. It is a fish that can be called the holy grail of healthy diet due to the multiple benefits it offers. It is great for hair, skin, joints and brain. Enriched with vitamins, minerals and, most importantly, omega-3, salmon is known to have uncountable benefits for the body. Due to these, salmon is also taken by many in the form of tablets, syrups and as frozen.

There are various varieties of salmon available in the market, such as sockeye, Atlantic and coho. In India, salmon is mostly imported from many parts of the world. Since salmon farming is significant to places like Canada, Norway and Scotland, it is used all over the world, especially in countries like United States of America. Indian subcontinent mostly gets imported frozen salmon, which is then later developed into various other forms.

How to consume salmon? 

 Salmon is a high-oil fish and can be consumed grilled, braised or baked along with steamed or blanched vegetables. Since salmon is available in many forms like tablets and oils, it can be consumed as instructed by your family physician.

How to store salmon?
Ensure that the freezer is set at a temperature of less than 4 degree Celsius. Keep the salmon either in a vacuum pack or plastic wrapping, as this pink-coloured fish gets affected by the smells of other foods.

Due to the rich nutrients it offers, salmon is a favourite amongst health experts, doctors and fitness enthusiasts. Following are the natural contents that it contains and things that make it a healthy fish:

Omega 3: 

Omega-3 are fatty acids which are essential for our body. Omega-3 is important as it promotes healthy joints and skin, reduces the risk of heart diseases and aids in brain development. According to many studies, it has been proved that consumption of omega-3 is good for cardiovascular health.

Omega-3 fatty acids also help in preventing high blood pressure, high cholesterol, diabetes, arthritis, depression, brain disorders, skin disorders and some types of cancers.

Omega-3 is specified and termed as an essential fatty acid because the body cannot synthesise it on its own and it must be obtained from what we eat. Since salmon is an oily fish, omega-3 occurs naturally in it. Omega-3, according to many scientists, may also lower the risk of many chronic diseases such as diabetes and depression.

Although there is no recommended daily intake of omega-3 fatty acids, many health experts and doctors recommend that adults should intake a minimum of 250-500 mg of omega-3 per day. The American Heart Association (AHA) recommends that adults should include at least 2 servings of omega-3 per week to get maximum benefits out of this fresh water fish.

Salmon contains essential amino acids that promote growth and help maintain muscle tissue mass. The protein found in salmon helps the body maintain a healthy metabolism which promotes weight loss. A 100 gm fillet or serving of salmon contains 22-23 grams of protein. Since proteins are the building blocks of our body, it is essential to get it from the most natural sources possible. Several studies have shown that salmon contains small bio-active protein molecules that provide special support for joint cartilage, insulin effectiveness and control of inflammation in the digestive tract.

To maintain a healthy active lifestyle, it is essential to include salmon in your diet because it contains vitamins like B1, B2, B3 and B5 in optimum quantities. These vitamins are involved in several important processes in our body. These processes include turning the food we consume into energy, creating and repairing DNA genes and reducing inflammation that can trigger possible heart diseases. According to recent research, Vitamin B of all kinds help to maintain optimal functioning of our brain and nervous system. Salmon is also rich in vitamin D. Vitamin D promotes healthy bones and teeth and may help decrease the risk of developing multiple sclerosis and some types of cancer.

Salmon is a source of minerals like phosphorous, potassium and selenium.

Wild salmon is quite high in potassium. In the fruit world, banana is considered to have high potassium levels. Salmon, on the other hand, contains 10% more potassium than a banana. Potassium needs to be consumed to help control your blood pressure level, especially in a country like India, where sodium levels in food is very high. This is because potassium helps prevent excess water retention in the body.

Phosphorous plays numerous roles in the body. These include building strong bones and teeth, maintaining a healthy heart and promoting good kidney health.

Another type of mineral found in salmon is selenium. Selenium helps fight heart diseases, some cancers and thyroid disease. A low intake of minerals contributes to reduced immune function, increased risk of developing some cancers and easily catching viral diseases.