This article was produced and financed by University of Stavanger

The level of this stress hormone rose in the programme participants (Photo: Colourbox)

Your workout could be working against you

In a Norwegian study, exercise made the participants lose less weight than expected. The reason may be increased physiological stress responses.

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University of Stavanger

The University of Stavanger (UiS) is located in Stavanger, Norway and has about 8,500 students and 1200 administration, faculty and service staff.

“It’s often said obese people should change their diet and exercise to lose weight,” observes Brynjar Foss.

“But their bodies may also need to deal with stress.”

Brynjar Foss is an associate professor in the Department of Health Studies at the University of Stavanger (UiS). He is the lead author among the four scientists responsible for the study that was published in the Journal of Exercise Physiology online in February.

Higher cortisol levels

The research covered 17 inactive people with a body mass index greater than 35 who took part in a 22 week programme for lifestyle change which involved exercise, diet and seminars. The control group contained 18 participants.

Brynjar Foss. (Photo: Ida Gudjonsson, UiS)

Despite their efforts, the participants lost less weight than expected from the amount of exercise they did and the changes they made to their eating habits.

The scientists believe this could be related to cortisol, since the level of this stress hormone rose in the programme participants.

Earlier research suggests that high levels of stress make weight loss more difficult.

Follow-up study: Still up after six months

Those who took part, not only had more cortisol than the control group immediately after the programme ended, but also retained an enhanced level six months later.

In addition, those participants who lost the most weight, had the lowest level of morning cortisol, a follow-up study shows. This study will be published in Journal of Exercise Physiology Online in June.

Small sample size

The researchers point out that the sample size is too small to draw any hasty conclusions. Moreover, considerable differences existed between those who took part – among that the medication they were taking.

However, these findings suggest that the hormone cortisol should be the subject of further research regarding overweight.

Fat and fit

In other words: This does not mean you should throw away your sneakers and go lie on the sofa.

Increased exercise and a change in diet contribute to a better quality of life for obese people, another Norwegian study shows.

This is a conclusion drawn from a one-year study, published in the Norwegian physiotherapy journal Fysioterapeuten.

“If you’re physically active, you can be in good health even if you’re overweight,” comments physiotherapist Martha Loland, who conducted the study for her MSc in health science at the UiS.

“The chances of suffering cardio-vascular disease are smaller for obese people who exercise than for those who don’t make any effort to keep fit.”


Read the Norwegian version of this article at

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