physical activity women

Does physical activity influence the health of future offspring?

Study finds an intergenerational benefit

April 10, 2018

Science Daily/DZNE - German Center for Neurodegenerative Diseases

Physical and mental exercise is not only beneficial for your own brain, but can also affect the learning ability of future offspring -- at least in mice. This particular form of inheritance is mediated by certain RNA molecules that influence gene activity. These molecules accumulate in both the brain and germ cells following physical and mental activity. Prof. André Fischer and colleagues from the German Center for Neurodegenerative Diseases (DZNE) in Goettingen and Munich and the University Medical Center Goettingen (UMG) report these findings in the journal Cell Reports.

 

Acquired skills do not modify the DNA sequence and therefore cannot be passed on to the offspring -- this belief was prevalent in the field of genetics for a very long time. However, in recent years, scientists have found some circumstances that refute this principle. A poor diet, for example, increases the risk of disease -- not only our own risk, but also that of our children. Lifestyle factors such as stress and trauma can also influence the next generation. Scientists call this phenomenon "epigenetic" inheritance, as it is not associated with changes in DNA sequence.

 

Inherited learning skills

 

Prof. André Fischer and colleagues investigated the inheritance of another acquired capacity: the ability for learning. It is well-known that physical and mental activity improves learning ability and reduces the risk of diseases such as Alzheimer's. In mice, the scientists showed that learning ability was passed onto the next generation by epigenetic inheritance. When Fischer and co-workers exposed mice to a stimulating environment in which they had plenty of exercise, their offspring also benefited: compared to the mice of a control group, they achieved better results in tests that evaluate learning ability. These rodents were also found to have improved synaptic plasticity in the hippocampus, a region of the brain important for learning. "Synaptic plasticity" is a measure of how well nerve cells communicate with each other. It thus forms the cellular basis for learning.

 

Next, the scientists investigated which mechanism could be responsible. For this, they focused on epigenetic inheritance by fathers and looked for its material basis in sperm. Sperm contains paternal DNA and also RNA molecules. The scientists therefore conducted experiments to find out about the role played by these RNA molecules in the inheritance of learning skills. For this, they extracted RNA from the sperm of mice that were physically and mentally active. These extracts were injected into fertilized egg cells. The mice that developed were also found to have enhanced synaptic plasticity and learning ability. Physical and mental activity therefore had a positive effect on the cognitive skills of the offspring. This effect was mediated through the RNA in the sperm.

 

Tracking down the responsible RNA

 

In further experiments involving injections of RNA extracts, the scientists were able to more closely identify the RNA molecules responsible for epigenetic inheritance: They showed that two so-called microRNA molecules -- miRNA212 and miRNA132 -- could account for at least some of the inherited learning capacity. microRNAs are control molecules that influence gene activity. "For the first time, our work specifically links an epigenetic phenomenon to certain microRNAs," says Fisher, a senior scientist at the DZNE Goettingen and the UMG.

 

The researchers also found that miRNA212 and miRNA132 accumulated in the brains and sperm of mice after physical and mental activity. It was previously known that these molecules stimulate the formation of synapses in the brain, thus improving learning ability. Through the sperm, they are transmitted to the next generation. "Presumably, they modify brain development in a very subtle manner improving the connection of neurons. This results in a cognitive advantage for the offspring," says Fischer.

 

It is known that physical activity and cognitive training also improve learning ability in humans. However, it is not so easy to study in humans whether learning ability can be inherited epigenetically. Nevertheless, the results obtained by Fischer and colleagues may point towards answers to this question. The researchers now intend to find out whether miRNA212 and miRNA132 also accumulate in human sperm after phases of physical and mental activity.

https://www.sciencedaily.com/releases/2018/04/180410132900.htm

More physical activity and higher intensity physical activity may significantly reduce risk of death in older women in the short term

November 6, 2017

Science Daily/American Heart Association

Using wearable devices to measure activity showed that the amount of moderate to vigorous intensity physical activity was associated with an up to 70 percent lower risk of death among older women in a four-year study. The amount of light intensity physical activity was not associated with death risk, but that may not negate the benefits of light activity for other health outcomes.

 

Researchers found the volume of light intensity physical activity or sedentary behavior was not associated with death rate. However, light intensity activity may be beneficial for other health outcomes not studied in this research.

 

Previous studies, which used self-reports, showed that active people have about 20 percent to 30 percent lower death rates compared to their least active counterparts.

 

This research, conducted from 2011 to 2015, is among the first to investigate physical activity, measured using a wearable device called a triaxial accelerometer, and a clinical outcome. The device is capable of measuring activity along three planes: up and down, front to back and side to side. These capabilities increase sensitivity to detect physical activity and allow for more precise measurements.

 

"We used devices to better measure not only higher intensity physical activities, but also lower intensity activities and sedentary behavior, which has become of great interest in the last few years," said I-Min Lee, M.B.B.S., Sc.D., the study's first author and professor of medicine and epidemiology at Harvard University's medical and public health schools in Boston, Massachusetts.

 

More than 17,700 women (average age 72) who were asked to wear the device for seven days, when awake, returned their devices. Data were analyzed from 16,741 compliant participants (i.e., their devices showed it was worn for at least 10 hours a day, on at least four days). During an average follow-up of approximately two-and-a-half years, 207 women died.

 

Researchers found:

 

·      More moderate to vigorous intensity physical activity (such as brisk walking) was associated with roughly a 60 percent to 70 percent lower risk of death at the end of the study among the most active women, compared to the least active.

·      More light intensity activity (such as housework and slow walking -- e.g., window shopping in a mall), or more sedentary behavior was not independently associated with death risk at the study's end. Researchers stressed this finding does not mean light activity isn't beneficial for other health outcomes not studied here.

 

Researchers chose this study population to begin addressing knowledge gaps, said Lee who is also an associate epidemiologist at Brigham and Women's Hospital in Boston. "Younger people in their 20s and 30s generally can participate in vigorous intensity activities, such as running or playing basketball. But for older people, vigorous intensity activity may be impossible, and moderate intensity activity may not even be achievable. So, we were interested in studying potential health benefits associated with light intensity activities that most older people can do."

 

The study's participants, selected from the Women's Health Study, were relatively healthy, and mostly white women, therefore the findings may have limited generalizability to other groups of people.

 

The findings support 2008 federal guidelines and American Heart Association that suggest at least 150 minutes a week of moderate intensity or 75 minutes a week of vigorous-intensity aerobic physical activity (or a combination of the two) and muscle-strengthening exercises two or more days a week.

 

"We hope to continue this study in the future to examine other health outcomes, and particularly to investigate the details of how much and what kinds of activity are healthful. What is irrefutable is the fact that physical activity is good for your health," Lee said.

https://www.sciencedaily.com/releases/2017/11/171106085826.htm

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