In a small study in the journal Experimental Physiology, researchers from Indiana University Bloomington and the University of Alabama at Birmingham, investigated the link cardiorespiratory fitness – the efficiency with which we transport oxygen to our tissues – and the diversity of bacteria in the gut.

They recruited 37 participants who had been successfully treated for non-metastatic breast cancer. This particular group was chosen because cancer treatment typically has a negative impact on metabolic health, including cardiorespiratory fitness.

The participants were asked to perform a series of graded exercises so that the researchers could assess their peak cardiorespiratory fitness, as well as total energy expenditure. The investigators also collected fecal samples from the volunteers and used them to analyse the participants’ gut microbiota.

What they found was that participants with higher cardiorespiratory fitness also had more diverse bacterial populations in the gut, compared with peers who had low cardiorespiratory fitness.

In addition, the results suggested that cardiorespiratory fitness was linked with about a quarter of the variance in bacterial species diversity and that this effect was independent of that produced by an individual’s body fat percentage.

Building a picture of health

The findings build previous research. In 2018 researchers from San Francisco State University reported on a study of 20 men and 17 women recruited from the university’s campus and tested their cardio fitness levels on a treadmill and then compared this to gut health. Reporting in the International Journal of Sport Nutrition and Exercise Metabolism indicated cardiorespiratory fitness was a far greater predictor of gut microbiota diversity than either body fat percentage or general physical activity.

In particular, those participants with the best cardiovascular fitness were found to have a higher ration of firmicutes-to-bacteroids in the gut. Firmicutes are associated with the metabolic process that help strengthen the intestinal lining and help prevent leaky gut syndrome.

This and other small studies which we have reported on are helping to build a picture of how connected our body systems are and provide information that can lead to more holistic approaches to managing health and wellbeing.

The international team of researchers from Brazil, Belgium, Australia, USA, UK and Sweden say their report is the first global meta-analysis to demonstrate that physical activity helps protect against depression.

The researchers began their study by collecting any past studies which looked at physical activity and depression. This yielded more than 13,000 papers from which they took the best 49, which involved 266,939 people from across Asia, Europe, North America, and Oceania. The average follow up time across these studies was 7.4 years.

“The evidence is clear that people that are more active have a lesser risk of developing depression,” said lead author Felipe Barreto Schuch, an exercise scientist at Universidade La Salle in Brazil. “We have looked at whether these effects happen at different age groups and across different continents and the results are clear. Regardless your age or where you live, physical activity can reduce the risk of having depression later in life.”

The findings, which were published in the  American Journal of Psychiatry, did not look at specific types of activity, but did take into account important factors like physical health conditions, smoking and body mass index. Even so they showed the value of engaging people in physical activity in a variety of settings, according to co-author Joseph Firth.

“The compelling evidence presented here provides an even stronger case for engaging all people in regular physical activity; through schools, workplaces, leisure programs and elsewhere, in order to reduce the risk of depression across the lifespan,” said Firth, a research fellow at the National Institute of Complementary Medicine at Australia’s Western Sydney University.

Physiological effects

The authors note that people with major depressive disorder are 50% less likely to be meeting the recommended physical activity levels (e.g., performing 150 minutes of moderate-intensity physical activity each week) compared with people without major depression.

They hypothesize that improving levels of physical activity reduces inflammation, increases neurogenesis, the process by which nervous system cells, known as neurons, are produced. This is important because increasingly research is suggesting that nerve cell connections, nerve cell growth, and the healthy functioning of nerve circuits have a major impact on depression. Exercise may also activate the endocannabinoid system, which has in the past been linked to exercise-induced euphoria, sometimes called ‘runner’s high’.

The study further suggests that physical activity may directly increase psychological factors such as self-esteem or perceptions of physical competence.

“Given the multitude of other health benefits of physical activity, our data add to the pressing calls to prioritize physical activity across the lifespan,” said co-author Brendon Stubbs, a postdoctoral research physiotherapist at King’s College London.

But you’ve got to commit

The findings come not long after another study from the University of Adelaide, published in the Journal of Affective Disorders, found that stopping exercise can result in increased depressive symptoms. The authors acknowledge that starting and maintaining exercise can have benefits on mental health – what they wanted to know was what happened if a person suddenly dropped their exercise regimen.

It’s not a questions that has had much focus but the research team found and reviewed studies that investigated the cessation of exercise in 152 adults. They had each undertaken at least 30 minutes of exercise, three times a week, for a minimum of three months.

“In some cases, ceasing this amount of exercise induced significant increases in depressive symptoms after just three days,” says Professor Bernhard Baune, Head of Psychiatry at the University of Adelaide and senior author on the paper.

Taken together these studies show the importance of not just starting but maintaining regular programme of physical activity in order to support good mental health.

• For other suggestions for addressing depression see our article: Depression – feeling your way out of the darkness

While it is known that moderate to intense physical activity reduces the risk of cardiovascular disease, the benefits of low-intensity activity have yet to be agreed upon.

So, researchers from Sweden’s Karolinska Institute followed a group of 851 people over 15 years looking at how different levels of physical activity affected the mortality rate due to cardiovascular disease (amongst other causes). Data on levels of activity were gathered in real time using motion trackers, and then correlated with official data on deaths and causes of death.

Get moving for a healthy life

Results, published in the journal Clinical Epidemiology, showed there are considerable health benefits to be gained not only from moderate or intense physical activity but also from low-intensity, everyday activity. Just a half hour a day of low-intensity activities reduces the risk of early death from any cause by 11% and the risk of early death from cardiovascular disease by a whopping 24%.

Replacing sedentary habits with physical activity of at least moderate level equivalent to a brisk walk, or higher intensity training, had an even greater effect on cardiovascular-related mortality.

Ten minutes of moderate to intense activity a day reduced the risk of death due to cardiovascular disease by 38%; with 30 minutes a day that number rose to 77%.

Previously the same team found that people who sit still for more than 10 hours a day have a 2.5 times higher risk of early death than people who sit for less than 6.5 hours a day. This new data adds top the picture with a strong message that daily activity is a key component of a long, healthy life.

Forty participants, 19 men and 21 women, were analysed in the study. All were non-smoking, moderately active men and women between the ages 22 and 50 years with a BMI between 19 and 30 kg/m2​. The researchers also narrowed down the study to include only participants who ate five or less portions of fruits plus vegetables on an average day.

The men and women were divided into two groups which received either 200mg of a lemon verbena supplement – Recoverben, a proprietary lemon verbena extract made by water extraction of organic dried lemon verbena (Aloysia citriodora​) leaves – or 200 mg of maltodextrin as a placebo.

Faster recovery

Participants were instructed to take their capsules each morning. In total, the study lasted 15 days – products were consumed for 10 days before an exhaustive exercise test, during the test day and four days after the test.

Perceived muscle soreness and general levels of pain post-exercise were used to judge the effectiveness of the lemon verbena.

Biochemical analyses were also performed to evaluate muscle damage and antioxidative capacity. Here the researchers were looking for levels of certain biomarkers: creatine kinase, glutathione peroxidase, and interleukin-6.

The researchers found that the participants who consumed lemon verbena benefited from less muscle damage as well as faster and full recovery. Compared to the placebo, the lemon verbena extract receiving participants had significantly less exercise-related loss of muscle strength over all time points, improved glutathione peroxidase activity by trend, and less induced pain by trend.

Polyphenols to protect muscles

According to the researchers, lemon verbena’s potential effects on exercise-induced muscle damage is similar to results seen in trials of other ingredients like ashwagandha, curcumin, pomegranate and blueberry. The key, they say, may be the high levels of antioxidants in these supplements.

“These natural ingredients are high in polyphenols, a trait shared by lemon verbena”, they said adding that, “It has been proposed, that polyphenols could be useful to prevent muscle damage or improve recovery.”​

The researchers concluded that lemon verbena extract is a “safe and well-tolerated natural sports ingredient ​[which reduces] muscle damage after exhaustive exercise.”​

Vital Solutions GmbH, a German ingredient company which owns Recoverben, funded the study and took part in discussions of the clinical trial design. However the results to mirror those of a 2011 study in which Spanish researcher also found that supplemental lemon verbena protected against oxidative damage, decreased the signs of muscular damage in participants taking part in a heavy running exercise.

But new research shows that keeping busy actually provides a variety of health benefits, including a lower risk of early death.

According to researchers at the University of California San Diego School of Medicine. The study, published in the Journal of the American Geriatrics Society, found women over age 65 who engaged in regular light physical activity had a reduction in the risk of mortality.

“Every movement counts,” said Andrea LaCroix, PhD, senior author of the study and professor in the Department of Family Medicine and Public Health at University of California San Diego. “A lot of what we do on a daily basis is improving our health, such as walking to the mail box, strolling around the neighbourhood, folding clothes and straightening up the house. Activities like these account for more than 55% of how older individuals get their daily activity.”

Monitoring activity

The 6,000 women in the study, which was published in the Journal of the American Geriatrics Society, were aged 65 to 99, were followed for up to four and a half years.

They wore a measuring device called an accelerometer on their hip around-the-clock for seven days while going about their daily activities. The study found that 30 minutes of light physical activity per day lowered mortality risk by 12% while an additional 30 minutes of moderate activity, such as bicycling at a leisurely pace or brisk walking, exhibited a 39% lower risk.

“Improving levels of physical activity both light and moderate could be almost as effective as rigorous regular exercise at preventing a major chronic disease,” said LaCroix, chief of the Division of Epidemiology at UC San Diego School of Medicine. “We don’t have to be running marathons to stay healthy. The paradigm needs to shift when we think about being active.”

The study also found that the benefit of light physical activity extended to all subgroups of women examined. That means benefits were seen in women of different racial/ethnic backgrounds, obese and non-obese women, women with high and low functional ability and women both older and younger than age 80.

It all counts

“Older people expend more energy doing the same kinds of activities they did when younger, so their daily movement has to accommodate for this,” said LaCroix. “Think of it as taking a pill (activity level) at different doses (amounts of time) depending on the age of the patient. It’s not one size fits all.”

Current national public health guidelines recommend 150 minutes of moderate to vigorous physical activity a week for adults. The guidelines recommend persons 65 and older follow the adult guidelines to the degree their abilities and conditions allow.

“Our study shows, for the first time using device-measured light physical activity in older women, that there are health benefits at activity levels below the guideline recommendations. With the increasing baby boomer population in the United States, it is imperative that future health guidelines recommend light physical activity in addition to more strenuous activity,” said LaCroix.

“When we get up from the couch and chair and move around, we are making good choices and contributing to our health.”

In a first of its kind international collaboration, researchers from Australia and the UK examined the effects of aerobic exercise on a region of the brain called the hippocampus, which is critical for memory and other brain functions.

Brain health decreases with age, with the average brain shrinking by approximately five per cent per decade after the age of 40.

Looking for clarity

Studies in laboratory animals have consistently shown that physical exercise increases the size of the hippocampus but until now evidence in humans has been inconsistent.

To gain some clarity on potential benefits in humans, the researchers systematically reviewed 14 clinical trials which examined the brain scans of 737 people before and after aerobic exercise programs or in control conditions.

The participants included a mix of healthy adults, people with mild cognitive impairment such as Alzheimer’s and people with a clinical diagnosis of mental illness including depression and schizophrenia. Ages ranged from 24 to 76 years with an average age of 66.

The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running. The length of the interventions ranged from three to 24 months with a range of 2-5 sessions per week.

Overall, the results – published in the journal NeuroImage – showed that, while exercise had no effect on total hippocampal volume, it did significantly increase the size of the left region of the hippocampus in humans.

Lead author Joseph Firth, a postdoctoral research fellow at Australia’s National Institute of Complementary Medicine at Western Sydney University, said the study provides some of the most definitive evidence to date on the benefits of exercise for brain health.

Long term benefits

“When you exercise you produce a chemical called brain-derived neurotrophic factor (BDNF), which may help to prevent age-related decline by reducing the deterioration of the brain,” Mr Firth said.

“Our data showed that, rather than actually increasing the size of the hippocampus per se, the main ‘brain benefits’ are due to aerobic exercise slowing down the deterioration in brain size. In other words, exercise can be seen as a maintenance program for the brain.”

Mr Firth said along with improving regular ‘healthy’ ageing, the results have implications for the prevention of ageing-related neurodegenerative disorders such as Alzheimer’s and dementia – however further research is needed to establish this.

Interestingly, he adds that physical exercise is one of the very few ‘proven’ methods for maintaining brain size and functioning into older age.

Lifestyle interventions such as exercise have been shown to aid in reducing the risk of death and the debilitating symptoms of chronic heart disease.

Heart disease patients who practice yoga in addition to aerobic exercise saw twice the reduction in blood pressure, body mass index and cholesterol levels compared to patients who practiced either Indian yoga or aerobic exercise alone, according to research presented at a recent international meeting of cardiologists.

Researchers in this study looked specifically at Indian yoga and aerobic training’s effect on the coronary risk factors of obese heart disease patients with type 2 diabetes.

Better together

The study looked at 750 patients who had previously been diagnosed with coronary heart disease. One group of 225 patients participated in aerobic exercise, another group of 240 patients participated in Indian yoga, and a third group of 285 participated in both yoga and aerobic exercise. Each group did three, six-month sessions of yoga and/or aerobic exercise.

The aerobic exercise only and yoga only groups showed similar reductions in blood pressure, total cholesterol, triglycerides, LDL, weight and waist circumference. However, the combined yoga and aerobic exercise group showed a two times greater reduction compared to the other groups. They also showed significant improvement in left ventricular ejection fraction, diastolic function and exercise capacity.

A little bit of everything

“Combined Indian yoga and aerobic exercise reduce mental, physical and vascular stress and can lead to decreased cardiovascular mortality and morbidity,” said Sonal Tanwar, PhD, a scholar in preventative cardiology, and Naresh Sen, DM, PhD, a consultant cardiologist, both at HG SMS Hospital, Jaipur, India.

He notes that Indian yoga is a combination of whole exercise of body, mind and soul, and a common practice throughout India and adds: “Heart disease patients could benefit from learning Indian yoga and making it a routine part of daily life.”

As it is with food, it seems that when it comes to exercise a little bit of everything is the healthiest approach.

There is copious evidence that regular practice can improve flexibility and strength, but according to new research it may also have positive effects on the physical structure of the brain.

The small study from Brazil used modern imaging techniques to examine the brains of older (aged 60+) female yoga practitioners’ brains.

Published in Frontiers in Aging Neuroscience, it included two groups of 21 healthy women matched for age, years of education, and level of physical activity.

A brain boost

A key difference, however, was that one group had practiced hatha yoga at least twice weekly for the eight years prior to the study and the other group had never practiced yoga, meditation, or other mind-body interventions.

Brain imaging allowed the researchers to measure the thickness of the brain’s cortex in each participant. They also administered several tests to evaluate the women’s performance of daily living activities and cognitive function, symptoms of depression, as well as height and weight.

Imaging showed that the regular yoga practitioners had greater cortical thickness in the left prefrontal cortex, in brain area associated with cognitive functions like attention and memory.

The results suggest that yoga could be an effective way to protect against cognitive decline in old age.

Focused attention

Previous studies have suggested that older adults with mild cognitive impairment have also shown improvements after a short yoga training program.

“In the same way as muscles, the brain develops through training,” explains Elisa Kozasa of Hospital Israelita Albert Einstein in São Paulo, Brazil, a researcher involved in the study, “Like any contemplative practice, yoga has a cognitive component in which attention and concentration are important.”

Yoga requires focused attention on muscles and posture, and this controlled attention and awareness engages the prefrontal cortex.

Meditation, which also involves controlled attention, has been found in prior research to increase blood flow to the prefrontal cortex and increase cognitive function. Future research may show us whether yoga’s effects on brain structure really can translate into prevention of age-related cognitive losses.

Researchers at New Mexico Highlands University (NMHU) found that the foot’s impact during walking sends pressure waves through the arteries that significantly modify and can increase the supply of blood to the brain. The research was presented at the recent APS annual meeting at Experimental Biology 2017 in Chicago.