Increasing vigorous physical activity reduces cardiometabolic risk factors already in primary school children, according to the doctoral thesis of Juuso Väistö, MHSc. The results indicate that the accumulation of cardiometabolic risk factors can be prevented already in childhood with physical activity and good physical fitness as well as by avoiding excessive sedentary time.
The prevalence of childhood overweight and obesity has increased alarmingly in recent decades and this is a global phenomenon. It is largely a consequence of unhealthy lifestyles, such as lack of physical activity, excessive sedentary behaviour, and unhealthy diet. Unhealthy lifestyles can lead to clustering of cardiometabolic risk factors, including excessive body fat, increased waist circumference, elevated fasting insulin and glucose concentrations, increased triglyceride levels, decreased high-density lipoprotein (HDL) cholesterol, and elevated blood pressure, already in childhood. Overweight and the associated accumulation of cardiometabolic risk factors in childhood predict an increased risk of developing type 2 diabetes and cardiovascular diseases in adulthood.
The purpose of Väistö’s doctoral thesis was to study the associations of different types and intensities of physical activity and sedentary behaviour as well as different components of physical fitness with overall cardiometabolic risk and individual cardiometabolic risk factors in a population sample of 506 Finnish
children aged 6-8 years as a part of the Physical Activity and Nutrition in Children (PANIC) study. Physical activity and sedentary behaviour were measured using the Actiheart® heart rate and body movement monitor and questionnaires which were filled out by the parents. Dietary factors were assessed by 4-day food records. Cardiorespiratory fitness was assessed comprehensively i.e. by a maximal cycle ergometer exercise test and neuromuscular fitness by the 50-meter shuttle run, the 15-meter sprint run test, the hand grip test, the standing long jump test, the sit-up test, the modified flamingo balance test, the box-and-block test, and the sit-and-reach test. Cardiometabolic risk factors included measurements of waist
circumference, fasting levels of insulin and glucose, triglycerides, HDL cholesterol, blood pressure, VLDL triglycerides, VLDL cholesterol, LDL cholesterol, and HDL triglycerides.
Lower levels of physical activity, particularly unstructured physical activity, as assessed by the questionnaire, were independently associated with higher levels of cardiometabolic risk factors in children independent of possible confounding factors. The excessive use of electronic media, particularly excessive television and video viewing, was also independently associated with higher levels of
cardiometabolic risk factors in children. The cardiometabolic risk was highest in those children who were physically least active and spent most time looking at electronic media. A change in vigorous physical activity, assessed by the Actiheart® monitor, was inversely associated and a change in sedentary time was directly associated with changes in the overall cardiometabolic risk and individual cardiometabolic risk factors over two years and these changes were independent of possible confounding factors. Higher body fat percentage and lower levels of physical activity were associated with poorer results in the 50-meter shuttle run test. Moreover, a higher body fat percentage was associated with poorer results in
the standing long jump test, the sit-up test, the box-and-block test, and the modified flamingo balance test. The associations of body fat percentage and physical activity with neuromuscular fitness were independent of each other. In addition, children with a higher body fat percentage and lower levels of physical activity had poorer results in the 50-meter shuttle run test, the 15-meter sprint run
test, and the standing long jump test than other children.
Physical activity was inversely associated with body fat percentage and truncal adiposity. These relationships strengthened with increasing intensity of physical activity. Children who participated in as little as 10 minutes of vigorous physical activity had 26–30 percent less total and truncal adipose tissue than children who did not have any vigorous physical activity. Even light physical activity was inversely
related to body fat percentage, but only at least moderate-to-vigorous physical activity was directly associated with cardiorespiratory fitness. By using isotemporal substitution models, it was observed that switching from 10 minutes spent in sedentary behaviours to an equivalent amount of vigorous physical activity would reduce the amount of total and truncal adipose tissue by 13 percent, a statistically
significant change.
Väistö’s doctoral thesis provides new insights into the associations between different levels of physical activity and physical fitness and risk factors for future cardiometabolic disorders in a general population of primary school-aged children. It observed that there is a direct association of sedentary behaviour with
elevated levels of cardiometabolic risk factors.
The doctoral dissertation of Juuso Väistö, Master of Health Sciences, entitled Physical activity, sedentary behaviour, physical fitness and cardiometabolic risk in a population sample of primary school-aged children - the Physical Activity and Nutrition in Children (PANIC) study, will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Associate Professor Katja Pahkala of the University of Turku, and the custos will be Professor Timo Lakka of the University of Eastern Finland. The public examination will be held in Finnish online on 5 March 2021 starting at 12 noon.
