Exercise as it relates to Disease/Can physical activity and fitness levels during adolescence predict the risk of cardiovascular disease during young adulthood?

This analysis is of the journal article "Physical Fitness and Physical Activity During Adolescence as Predictors of Cardiovascular Disease Risk in Young Adulthood. Danish Youth and Sports Study. An Eight-Year Follow-Up Study" by Hasslelstrøm, Hansen, Froberg & Andersen (2002).

What is the background to this research?
Cardiovascular disease (CVD) is currently the leading global cause of death, being responsible for 17.3 million deaths per year. This number is also expected to increase to upwards of more than 23.6 million by the year 2030. Physical Inactivity is a key contributor to an individual’s Cardiovascular disease risks. Cardiovascular disease risks can be categorised into two different types; modifiable risk factors and non-modifiable risk factors. Modifiable risk factors are the factors that can be reduced with treatment such as physical inactivity, blood pressure, blood glucose and lipid levels, inflammation and blood clotting factors. Other treatable factors can include your diet, smoking and drinking status as well as being obese. Whereas non-modifiable risk factors are those that cannot be reduced or changed by treatment such as a family history of cardiovascular disease or having diabetes. The more risk factors an individual has, the higher the chance of developing cardiovascular disease is. In the 2014-15 year 56% of all adults in Australia were not meeting the physical activity standards. Physical activity can decrease the amount of risk factors an individual has for Cardiovascular disease. Just an hour of vigorous exercise every day can decrease the risk of coronary heart disease by 30%. With exercise being such a significant factor contributing to an individual’s health, it is important that they have good health-promoting behaviours. These behaviours formed early during adolescence can be associated with increased levels of behaviours that promote healthy living as adults.

Where is the research from?
Hasslelstrøm, et al. study was conducted at the University of Copenhagen, Denmark with the Institute of Exercise and Sports Sciences as well as the University of South Denmark with the Institute of Sport Science and Clinical Biomechanics.

What kind of research was this?
The research was a longitudinal, quantitative study over the span of eight years. It used a questionnaire each year as a one-year recall as well as measurements being taken at the beginning and end of the eight year follow up.

What did the research involve?
Hasslelstrøm, et al (2002) selected a random group of school children aged between 15 to 19 years old for an 8 year follow up study which involved a questionnaire that assessed physical activity. A one-year recall was also used to determine how much physical activity of each individual was doing. The questionnaires also gathered information about alcohol and smoking habits as well as marital status and occupation. Measurements such as V˙O2max, blood pressure, height, weight and skinfolds were also taken in the first and eighth year.

What were the basic results?
Hasslelstrøm, et al. showed that throughout the eight years, changes in physical activity levels in men resulted in changes in waist girth and body fat percentage. As well as a significant drop of physical activity levels in women. The data also showed that changes in VO2max resulted in changes of triglycerides, cholesterol and HDL-C in men and systolic blood pressure, body fat percentage, triglycerides and overall risk score in women. There was not a significant relationship between strength and cardiovascular disease in both men and women. There was a good relationship between strength and body fat percentage in only men and a good relationship between changes in physical activity level and HDL-C and triglycerides in women.

How did the researchers interpret the results?
The interpretation of the research results was that there were strong relationships between VO2max changes and all CVD risk factors in men and in women, changes VO2max and physical activity level, cholesterol and body fat %. Due to the type and length of the research, they had to take a few things into consideration. The first is that the research involved the use of a questionnaire. Individuals may alter their answers to score or over or underestimate the number of hours their physical activity is which may contribute to inaccurate data. Another influencing factor is the significant drop in sport and physical activity in females around adolescence. This could also be a high contributing factor to the results for the females having more significant changes over the eight years.

What conclusions should be taken away from this research?
Physical activity levels can play a significant role in Cardiovascular disease risk in adulthood. However, it is the health-promoting behaviours formed during adolescence that are carried on into adulthood. The more of these behaviours such as physical activity levels, healthy diet and sleep can have a positive influence on Cardiovascular disease risk factors. Further studies should take into account the significant decrease in female physical activity and sport-based behaviours as well as the potential bias in the answers of the questionnaire regarding an individual's physical activity level.

What are the implications of this research?
The study conducted by Hasslelstrøm, et al. found that though physical activity may not be directly linked with reducing cardiovascular disease incident rates it does reduce the risk factors contributing to cardiovascular disease. These factors are listed above. This means that with lower rates of drinking, smoking and physical inactivity as well as improved diet, blood pressure, blood glucose and blood lipids the likelihood of developing cardiovascular should be reduced. Further studies are needed to develop strategies that help to form health-promoting behaviours during childhood and adolescence which can then be carried on into adulthood.