Exercise provides healthier fat

With exercise, our fat cells behave differently and help deter diabetes. This has been demonstrated by a new American study conducted using mice and data from tests in which two students from the Norwegian School of Sports Sciences (NIH) played key roles.

Overweight man on an exercise bike
Being overweight increases your exposure to diabetes. By “stimulating the fat”, your actual fatty mass functions better. This has been demonstrated by the study on mice, based on data from an NIH study conducted in 2013. Photo: Shutterstock
Jørgen Jensen portrait
Jørgen Jensen is a Professor of sports biology at the Department of Physical Performance at the NIH. He coordinated the tests conducted at the NIH during the study. Photo: NIH ALT: Jørgen Jensen portrait

The results of the study have provided impressive advances in research into diabetes. They may prove extremely important, not least given the high number of people who suffer from type 2 diabetes.

People who have type 2 diabetes are much more vulnerable to severe health issues, and many die at a much younger age than would have been normal. Moreover, their families and society have to pay a high price. The families because of worries and a too early loss, the society because of billions spent on long-term treatment.

  • It is estimated that approximately 300,000 people live with type 2 diabetes in Norway alone. Most are diagnosed between the age of 50 and 70; one in nine persons over the age of 80 live with the disease.
  • Type 2 diabetes, formerly also known as age-related diabetes, is caused by a combination of genetic factors, overweight, poor diet and not enough exercise.
  • Type 2 diabetes normally develops slowly and with age, can cause a variety of ailments, from fatigue and depression to serious complications such as kidney failure, blindness, amputations or even premature death.

Stimulating the fat

A new study has now shown that the fatty tissue is in itself important:

  •  for burning sugar (or glucose, as the professionals call it),
  •  for reducing the volume of fat in your body and thereby also,
  •  reducing the risk of diabetes.

To achieve this, we have to “stimulate the fat”. Physical activity helps.

Old news?

We are all aware that physical activity helps, but the fact that it also affects the fatty tissue which in turn affects so much else, is all new.

The foundations for the study on mice in the USA were laid at the NIH, with good help from two Bachelor students. So – this story relates both to an old study from the NIH but which remains of international importance, and to praise for two students.

  • The number of new cases of type 2 diabetes has doubled over the last 20 years. Costs have increased correspondingly.
  • Type 1 and type 2 diabetes cost Norwegian society NOK 4 to 7 billion annually.
  • If a person with diabetes develops complications, the cost for society is around 25 times higher.
  • 12,000 “new” persons develop type 2 diabetes every year in Norway alone. The number of new cases has dropped in recent years, thought to be due to a new standard for diagnosis.
  • The number of younger persons who develop type 2 diabetes is on the increase. Previously, it was mostly older people who developed type 2 diabetes, but now it is common among 20 to 30-year-olds. They live longer with the disease, increasing the risk of complications.

Figures from the Norwegian Diabetes Association, April 2019

Exercise for a better balance

The story all starts in 2013 when the two students, Kristoffer Kolnes and Daniel Tangen, were assigned responsibility for preparing a weight training programme for a major study. The programme involved monitoring 26 middle-aged men (half of them overweight and with poor blood sugar regulation) over a period of 12 weeks, with physical exercise four times a week. (“Overweight” is normally understood as having a BMI above 25. It is easily calculated.)

All the participants improved their oxygen intake, strength and – most importantly: their insulin sensitivity.

Put simply, this means that the insulin in the body, tasked with keeping our blood sugar in balance, starts working properly again. (Type 2 diabetes is caused when the insulin stops working as it should, and that insulin levels are too low – see fact box.) When our blood sugar is out of balance, you are more exposed to a number of health problems.

Complex connections

After the period of 12 weeks, the participants were voluntarily measured and tested. Biopsies (small tissue samples) were taken from their muscles and fatty tissue, with measurements taken of the volume of muscle and fatty tissue, and tests were performed of their so-called RNA.

This is quite a complex process technically. However, the vast data material it produced, including printouts from 12,000(!) genes from each tissue sample, made it possible to identify which genes are associated with, e.g., maximum oxygen intake and – insulin sensitivity.

Important female hormones in men

The professionals in the USA are now benefiting hugely from this study. Professor Andrea Hevener and some of her colleagues at the UCLA in California have utilised the data for a major experiment using mice. And they have established that so-called oestrogen receptors are important for both insulin sensitivity and metabolic rate (via the mitochondria in the fatty tissue).

Oestrogen is the female hormone, of course, but men – including those who took part in the NIH tests – have some oestrogen in their bodies. And this has an impact on fatty tissue. Naturally, our metabolic rate is important in relation to how much fat you have on your body.

The links are complicated, but this does mean:

  • That fatty tissue helps control our metabolic rate and, as a result, both our health and weight.
  • That exercise has an effect on the fatty tissue, improving both insulin sensitivity and blood sugar balance and reducing the volume of fat on our bodies.
  • That a healthier fatty tissue helps reduce the risk of type 2 diabetes.

Exercise and tests

“The good part is that the work our NIH students carried out has been decisive in advancing the research, and is used by scientists worldwide,” explains Jørgen Jensen. He is a Professor at the Department of Physical Performance at the NIH, and has followed the two students throughout the process.

Overweight man jogging

  • The study from the NIH is part of an impressively vast study: MyoGlu
  • The NIH conducted exercise programmes involving strength and stamina, testing the participants before and after the study.
  • The NIH also took biopsies of fatty tissue and muscles, and analysed a number of different types of data.
  • Oslo University Hospital also carried out a number of tests, including RNA sequencing, MR scans and hormone analyses.
  • In total, this comprised a comprehensive database, still utilised by researchers as a link and for data.

 

“NIH has a high level of expertise in preparing exercise tests, so-called exercise interventions, and conducting physiological measurements, and we are proud to have created the foundations for a data set that is utilised so extensively,” he says.
To date, the data from the NIH has formed the basis for close to 30 different scientific articles.

“You seem quite proud of your old students…?”

“Absolutely. We would not be able to carry out successful and comprehensive exercise studies without skilled students. A number of other students were also involved in the project, but these two played a very central role. They were, for example, responsible for the entire weight training programme.”

Important in combating diabetes

The study on mice uncovered several new mechanisms that may prove very important in deterring diabetes. Once you have found such connections or mechanisms, you can then start to find ways to adjust them.

“This means that it may not only be necessary to exercise to get healthier, but that we can search for other ways to affect the processes in our bodies and find medical treatment for those who do not exercise,” says Jørgen Jensen.

He also believes that many people will be happy to know what happens in their bodies when they exercise. “Hopefully, now you know this.”

Not surprised

Daniel Tangen portrait
Daniel Tangen is currently the coach of the women's national team in alpine skiing. He took part in conducting the study as a Master’s student at the NIH in 2013. Photo: Private

One of the two students mentioned by Jørgen Jensen, Daniel Tangen, says that he is not surprised by the praise they have received or the value of the study.

“There were very few proper studies involving exercise for insulin resistance, and this was a comprehensive study during which we made a number of new discoveries,” he explains. Daniel Tangen is currently working as the coach for the national women’s alpine skiing team.

He wrote his Master's thesis at the NIH on the basis of the study. His thesis related to strength and stamina, comparing persons with normal weight with overweight persons with insulin resistance. “Regular exercise is incredibly important for persons with type 2 diabetes,” he agrees.

“Is always nice to be praised by an old teacher, but I’m not that surprised. We carried out a major study, which proved important.”
Nonetheless, he claims that the lessons he learned about tests during the study are more important.

“I use this knowledge every day at work, to see whether the exercise programmes we have – and what parts of them – actually have the results we are aiming for.”
The other student, Kristoffer Kolnes, is halfway through a doctoral degree on fat cells and diabetes at the University of Southern Denmark in Odense, Denmark.

Achieved healthier fat

Several other heavyweights (pardon the pun) in this field took part in the project, such as stamina expert, World Champion and former national team coach in orienteering, Egil Johansen and Hans Kristian Stadheim, an expert in maximum O2 intake. Other researchers outside the NIH also took part, along with a number of students

What happened to the participants on the exercise programme?
They did not lose weight, even though they lost on average two to three kilograms of fatty mass. This was literally weighed up for in increased muscles.

However, the fat remaining also had improved function. Good fatty tissue produces, for example, leptin, a hormone that controls hunger.

“Without leptin, you would be hungry all the time, and things would go wrong very quickly,” explains Jørgen Jensen. “It is a fact that fatty tissue communicates with other types of tissue, and a healthier fatty tissue – with exercise – sends more correct messages to your body.
Not only were the participants fitter, they also had healthier fatty tissue after the study.”