Brain researcher: "The brain is perhaps the organ that is strengthened the most by exercise"
People who are regularly physically active can halve their risk of Alzheimer's disease, studies show. Why doesn't everyone take advantage of such a readily available medicine?
When Professor Linda Hildegard Bergersen first read about the effects of exercise on the brain, she thought:
"How dare you not exercise?"
Especially because it is such an incredibly accessible 'medicine'.
Linda Hildegard Bergersen is Professor of Physiology at the University of Oslo and Professor of Ageing and Neurobiology at the University of Copenhagen.
"We have changed our lifestyles dramatically in a very short time," she continues:
"I was born in the 1960s and belong to a generation that walked, cycled or skied to school. Today, a child who does not participate in some form of organized sport risks sitting all day."
At least 20 minutes every day
Norway's Directorate of Health (a professional and regulatory body under the Ministry of Health and Care Services) recommends that we exercise at moderate intensity for a total of 2.5 hours per week. That's about 20 minutes a day.
Most people know that exercise reduces the risk of cancer and cardiovascular disease, but the fact that it also strengthens the brain and can help reduce the risk of Alzheimer's may come as a surprise to many.
It is precisely the latter that ageing researcher Linda Hildegard Bergersen is particularly interested in.
She knows that the brain is very plastic, even as we age. And that means we can influence it ourselves - well into old age.
The hippocampus shrinks
One important change in the brain is that the hippocampus shrinks as we age.
The hippocampus is an area of the cerebrum that plays a crucial role in memory, learning and orientation.
"It's a normal part of ageing," explains Linda Hildegard Bergersen.
'But when we take pictures of the brain, we see that this shrinkage occurs more slowly in people who are physically active. In these people, new, fresh blood vessels form in the brain tissue, precisely in the area where memory is located. New blood vessels make it easier for the brain tissue to access oxygen and nutrients. It gets more 'food'."
Physical and social training
It's not just about making sure the brain is nourished. Researchers also know that physically active people form new nerve cells in the brain.
The brain produces new brain cells throughout life, but production decreases as we age.
"That's why exercise is not enough when we reach the age of 60 or older. We also need to use our brains."
Of course, we can sit down at the kitchen table and do crossword puzzles or sudoku, but the best way to exercise the brain is when we are with other people.
"One of the smartest things you can do is to be physically active with other people. Then we get exercise and the brain gets the opportunity to be social," explains Linda Hildegard Bergersen, who adds:
"In this way, we create extra new nerve cells in the brain."
If exercise were a pill, we would all take it
Ole Petter Hjelle, a medical doctor and neuroscientist, is also concerned about how few of us know that exercise is practically medicine - and this also applies to healthcare.
"When I talk about the solid and robust studies about how beneficial exercise is - not just for the musculoskeletal system - but also for the brain, people are very surprised."
"If physical activity was a pill, we would all take it," Ole Petter Hjelle told Videnskab.dk's Norwegian sister site forskning.no in 2018.
The reason why even healthcare professionals are not aware of all the benefits is that it is a tool that has not really entered the doctors' toolbox, he says.
"When I was studying medicine, I had 140 hours on pharmacology and 0 hours on physical activity as medicine. It's not much better today. At the medical school in Oslo today, students have 45 minutes on this topic over the course of six years," he points out.
- Why is this the case?
"There are probably several reasons, but I think one of the challenges is that there is no industry behind it that markets exercise as a real treatment option in line with what the pharmaceutical industry - of course - does with drugs," says Ole Petter Hjelle.
How much exercise do we need?
Scientists agree that exercise is good, but how much exercise we need to boost our health and stay healthy is another matter altogether.
Scientists have been discussing this for years. Perhaps it is also because we are all different.
Certainly, in recent years, researchers have become more aware that many medicines need to be tailored to each individual. Perhaps this is also the case for physical activity and its impact on brain health.
"Physical activity three times a week may be enough for one person, but another person may need to exercise five times a week," says Linda Hildegard Bergersen, she continues:
"We know that some people respond very well to exercise, while others respond less well. Some of us take longer to get fit than others."
It's important not to overcomplicate it, says Linda Hildegard Bergersen, because the most important thing is to get your heart rate up.
Does the effect improve with more exercise?
How much exercise is needed to most effectively keep the brain healthy is the subject of a large ongoing study in the US.
Arthur Kramer, a professor at Northeastern University in Boston, has been studying the effects of physical activity on the brain for 30 years.
Populations around the world are ageing, and a daily exercise session can be the difference between a sick and a healthy old age.
Arthur Kramer's research team has previously observed that problem-solving ability increases when running or walking at a brisk pace.
But researchers know little about how much exercise is needed. Will the effect be even better if you are more active? Or is a small amount of activity enough? This is what researchers in Boston are studying, according to svt.se.
Arthur Kramer tells the Swedish news channel that the way we look at exercise today is a bit like the way we looked at smoking 20 years ago. We have gradually begun to understand how harmful to health a sedentary life is.
Never too late
One of the most important messages he gives his patients as a doctor is that it is never too late to start, says Arthur Kramer.
'I have a number of patients who have been very inactive and who think that now that they are older there is no point. This is wrong. It can have tremendous brain results - no matter when in life you start."
"The brain is perhaps the organ that is strengthened the most. Virtually all areas and functions of the brain are strengthened when we move. We become more alert. We get a better memory. We become more creative. We cope better with stress."
Difficult to get up from the sofa
Even though we are told how much exercise benefits both body and mind, it is very difficult for many people to get off the couch. And that's not surprising, according to Ole Petter Hjelle.
"Our brain has an evolutionary predisposition to laziness. Our ancestors were physically active because they had to be. They had to flee from the enemy and run to get food, but the rest of the time they stayed still to conserve calories because they didn't know when they would get their next meal."
"The brain wants us to save calories. And the brain we have today has basically not changed since the days when we were hunter-gatherers on the savannah. It is still programmed for laziness when we can get away with it. To overcome the lazy brain, he believes it is a good idea to focus on the immediate benefits of exercise and less on what happens in the long run.
"Many of the benefits are immediate; when we go for a walk in the fresh air, our mood improves, and much the same happens to our attention and memory.
Found receptors for lactic acid
Of course, researchers are also keen to find out what actually happens in the brain when we are physically active. What is it that creates the positive effects?
Linda Hildegard Bergersen and her research team at the University of Oslo have shown that lactic acid plays an important role.
When muscles work intensively, this can activate a specific receptor for lactic acid, which in turn causes blood vessels to grow and increases the density of small blood vessels in the brain.
This regeneration of blood vessels can counteract the development of cognitive decline and age-related dementia. Nerve cells are simply maintained.
The research results were published in the journal Nature Communication in 2017, and the researchers also wrote a feature article in Aftenposten in the same year.
