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How regular exercise lowers death risk

By Chukwuma Muanya
05 February 2019   |   4:23 am
People who spend a lot of time sitting are more likely to experience some adverse health conditions, such as obesity.

PHOTO: Korea Bizwire

People who spend a lot of time sitting are more likely to experience some adverse health conditions, such as obesity.

However, a new study has revealed that even a small amount of exercise can have a significant impact on arguably the most important thing of all: lifespan.

The scientists concluded that swapping just 30 minutes of inactivity for some form of exercise might reduce a person’s chance of an early death.

In 2017, Keith Diaz — an assistant professor of behavioral medicine at Columbia University Vagelos College of Physicians and Surgeons in New York City, NY — led a study into the link between time spent sitting and mortality rates.

He published the findings in the Annals of Internal Medicine. They showed that adults who sat for an hour or more were more likely to experience an early death than those who sat for the same amount of time in total but got up for periods in-between.

More significantly, the study found that those who sat for less than half an hour at a time had the lowest early death risk.

Diaz and his team concluded that a movement break every 30 minutes could reduce death risk. However, they did not know how long or how intense this exercise needed to be to make an impact.

Diaz has led a new study, and it looked into just that. Now published in the American Journal of Epidemiology, it studied 7,999 people aged 45 and above.

These volunteers were all part of the Reasons for Geographic and Racial Differences in Stroke cohort study, conducted in 2009–2013.

For at least four days, each individual wore an activity monitor. This tracked how much physical activity they were doing each day, as well as how intense this exercise was.

The scientists studied the mortality rates of participants throughout 2017, and they used the data to analyze how activity and sitting time affected early death risk.

They saw that substituting 30 minutes of sitting with low-intensity exercise could reduce early death risk by 17 percent.

This doubled to a 35 percent reduction for moderate- to high-intensity exercise.

“Our findings underscore an important public health message that physical activity of any intensity provides health benefits,” explains Diaz, who also found that even a minute or two of activity had some advantage.

An important feature of the findings is that people who are unable to partake in vigorous exercise can still find a way to reduce their risk. As Diaz points out:

“If you have a job or lifestyle that involves a lot of sitting, you can lower your risk of early death by moving more often, for as long as you want and as your ability allows — whether that means taking an hour-long high-intensity spin class or choosing lower-intensity activities, like walking.”

Other than death, the researchers did not study specific health concerns. For this reason, there is the potential that exercise does not have the same impact on the onset or progression of certain diseases. However, some scientists plan to include these aspects in future analyses.

Diaz reports that the team is now aiming “to look at the risk of specific cardiovascular outcomes, such as heart attack, heart failure, and cardiovascular-related deaths, associated with physical activity versus sedentary behavior.”

Until then, taking a movement break every half an hour is the best advice researchers have.

Also, according to a new study, going for a daily walk or bike ride can shave 10 years off your ‘brain age’.

Researchers found that regular aerobic exercise boosted essential gray matter in all adults, even as young as 20 years old.

Even climbing the stairs improve the thinking skills of the students they examined, scientists said.

The positive effect of physical activity increased with age: people aged 40 seemed 10 years younger, while 60-year-olds seemed 20 years younger.

The researchers say the findings could help our understanding of non-pharmaceutical methods to balance brain aging, and could even reduce the risk of dementia.

Study author Professor Yaakov Stern, of the Taub Institute for the Research on Alzheimer’s Disease and the Aging Brain at Columbia University in New York, said: “As people age, there can be a decline in thinking skills.

“However our study shows getting regular exercise may help slow or even prevent such decline.

“We found all participants who exercised not only showed improvements in executive function but also increased the thickness in an area of the outer layer of their brain.”

The study published in Neurology found exercise specifically improved neurons in areas that control executive function.

These relate to a person’s ability to regulate their own behavior, pay attention, organize and achieve goals.

Dr. Stern and colleagues followed 132 people aged 20 to 67 who were randomly assigned to six months of either aerobic exercise or stretching and toning four times a week.

Those in the former group chose from activities including walking on a treadmill, cycling on a stationary bike or using an elliptical machine that simulates stair climbing.

The researchers found these were twice as effective as stretching and toning. Aerobic exercisers improved their overall scores on executive function tests by 0.50 points.

This was a statistically significant difference from those who did stretching and toning – who progressed by 0.25 points.

At 40, the improvement was 0.228 standard deviation units higher in those who exercised compared to those who did stretching and toning. At 60 it was 0.596 more.

Stern said: “Since a difference of 0.5 standard deviations is equivalent to 20 years of age-related difference in performance on these tests, the people who exercised were testing as if they were about 10 years younger at age 40 and about 20 years younger at age 60.”

He added: “Since thinking skills at the start of the study were poorer for participants who were older, our findings suggest that aerobic exercise is more likely to improve age-related declines in thinking skills rather than improve performance in those without a decline.”

None of the participants smoked or had dementia. They also did not exercise at the start of the study and had below average fitness levels. The aerobic and stretching groups were equally balanced for age, sex, education as well as memory and thinking skills at the outset.

They worked out at a fitness center and checked in weekly with coaches monitoring their progress. They all wore heart rate monitors as well.

Thinking and memory skills were evaluated at the start as well as at three months and at the end of the six-month period.

Participants in the exercise group ramped up their activity during the first month. During the remainder of the study they trained at 75 percent of their maximum heart rate.

People in the stretching and toning group did exercises to promote flexibility and core strength.

Researchers measured participants’ aerobic capacity using a cycling machine called an ergometer that estimates exercise intensity. Participants also had Magnetic Resonance Imaging (MRI) brain scans at the start and end.

This identified an increase in the thickness of the outer layer of the brain in the left frontal area in the entire aerobics group – suggesting it contributes to brain fitness at all ages.

“Our research confirms that exercise can be beneficial to adults of any age,” said Stern.

Also, researchers have found that formerly sedentary young adults who were instructed to exercise regularly for several weeks started choosing healthier foods without being asked to.

In the latest evidence that it’s worth sticking to your health-focused New Year’s resolutions, researchers at the University of Texas at Austin have found that exercising regularly is linked to better eating habits.

The new study, published this week in the International Journal of Obesity, looked at 2,680 young adults who were not exercising regularly or dieting. Scientists found that after exercising for several weeks, formerly sedentary study participants were more likely to choose foods like lean meats, fruits and vegetables, while preferences for fried foods, sodas and other unhealthy options decreased.

Participants were instructed not to change their diets in any significant way, but it happened anyway. Although this study did not examine the mechanism at work behind the changes, previous research has found that moderate exercise can reduce a preference for high-fat foods in animals through changes in dopamine levels. Several studies also have shown a relationship between the intensity of exercise and the amount of appetite-regulating hormones in the body.

“The process of becoming physically active can influence dietary behavior,” said Molly Bray, corresponding author of the paper and chair of the Nutritional Sciences department at UT Austin and a pediatrics faculty member at Dell Medical School. “One of the reasons that we need to promote exercise is for the healthy habits it can create in other areas. That combination is very powerful.”

Bray says what drives food-preference changes when people exercise would probably be consistent across a wide span of ages. The study examined people between the ages of 18 and 35, a period of young adulthood critical for forming healthy habits. Previous studies have found that considerable weight gain occurs during the college years and that being mildly to moderately overweight at age 20-22 increases the risk of obesity later in life.

“Many people in the study didn’t know they had this active, healthy person inside them,” Bray said. “Some of them thought their size was inevitable. For many of these young people, they are choosing what to eat and when to exercise for the first time in their lives.”

The participants in the study were students at the University of Houston and the University of Alabama at Birmingham. Participants who said they exercised less than 30 minutes a week at the beginning of the study started 30-minute aerobic workouts three times a week for 15 weeks, with instructions not to change their diet in any significant way. The exercise sessions consisted of 30 minutes of aerobic exercise at 65-85 percent of the person’s age- and gender-specific maximum heart rate, along with a 5-minute warmup and a 5-minute cool down. Participants wore heart-rate monitors and could choose from a variety of exercise types, such as on stationary bikes, treadmills or elliptical machines.

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