Date Published: 20 June 2018
More positive effects of exercise, especially for obese people
It has been reported that physical exercise can reduce inflammation in obese people by changing the characteristics of their blood1. This suggestion follows from a recent study2 by a group of researchers based at the Department of Kinesiology and Community Health at the University of Illinois (IL, USA) who investigated the response of circulating progenitor cells (CPCs) to a 6 week endurance exercise training program, with particular interest in the responses of CPCs in lean compared with obese adults.
This work is important because it reveals new information that might be useful to experts and others concerned about how best to deal with the problems of obesity and its consequences for both individuals and the wider societies they are part of, including for example the provision of health-related services in areas in which a significant proportion of adults are overweight. Adult obesity is defined by the World Health Organization3 (WHO) as a Body Mass Index (BMI) of 30 or more. According to recent global estimates from WHO3 :
- In 2016, more than 650 million adults were obese.
- Overall, about 13% of the world's adult population (11% of men and 15% of women) were obese in 2016.
- Worldwide the prevalence of obesity close to tripled between 1975 and 2016.
The many health risks of obesity include increased possibilities of health problems such as heart disease and type 2 diabetes. Many of the health issues associated with obesity are due to chronic inflammation. Although inflammation is a natural process by which the body responds to harm, in obese people it can become long term which can lead to damage to otherwise healthy tissue.
Scientists have explained that certain blood cells, specifically those are formed from stem cells within the body, are more likely to cause inflammation. They went on to say that if these cells are made in larger quantities than normal they can move to organs in the body and cause them to malfunction1. The recent research from the University of Illinois has demonstrated that exercise alters the characteristics of these blood forming stem cells, reducing the number of blood cells likely to cause inflammation. This provides a new explanation for how exercise might improve the health of obese adults.
More about this study
The researchers recruited two categories of participants for this study, seventeen young, lean adults and ten young, obese adults (previously sedentary people who were otherwise generally healthy). The scientists collected detailed physiological information about all of the participants both before and after completion of the six-week exercise program. The exercise program itself involved three bicycling or treadmill running sessions per week with each session lasting approx. an hour. Blood was collected from each participant both before and after the exercise training so that the scientists could count and study the blood-forming stem cells. Overall it was found that exercise reduced the number of blood-forming stem cells associated with the production of the type of blood cells responsible for inflammation.
The research group is now interested in finding out how these changes in blood cell populations might affect the function of muscle and fat involved in energy consumption and storage among people with obesity. They are also looking to investigate whether these effects of exercise on blood cells are also seen in other chronic conditions associated with increased inflammation.
Principal Investigator, Dr Michael De Lisio was pleased with the impact that the exercise intervention had on some of the participants' exercise habits. He said1:
"This research is important because it helps us understand how and why exercise improves the health of people with obesity.
_ After participating in the exercise intervention, some participants were inspired to participate in our local half-marathon. This enthusiasm for exercise and building the habit of increased physical activity is one of the most rewarding aspects of conducting these types of human exercise trials".