The researchers, in collaboration with investigators from Technische Universität München, and the universities of Konstanz and Bayreuth, all in Germany, analyzed 243 women and 252 men who were an average age of 45 at study baseline.
The participants were followed-up from 1992 to 2010. They were required to complete a series of questionnaires and carried out medical and fitness tests in the years 1992, 1997, 2002 and 2010.
The researchers used a four-stage "biopsychosocial model" to pinpoint factors that could have an impact on future health and fitness.
The first stage included environmental factors, such as socioeconomic status and migration background. The second stage consisted of personal factors, including social support, stress management strategies and the feeling of coherence.
Behavioral factors, such as smoking, physical exercise and nutrition habits made up the third stage, while the fourth stage consisted of physical fitness and health.
Health and fitness habits 'affect us 18 years later'
From their analysis, the investigators found all factors in all four stages had both a direct and indirect impact on participants' physical fitness and health in 1992.
Researchers found that current health and fitness habits may influence our overall health and fitness over the next 18 years.
The areas that had the most influence included migration background, socioeconomic status, stress management strategies, expectations of exercise impact, and physical exercise and nutrition habits.
However, the researchers found that nutrition and physical exercise habits reported at the baseline of the study affected the fitness of participants during the following 18 years later, up until 2010.
The investigators say they also found that migration background and socioeconomic status indirectly influenced health habits in the 18 years after study baseline.
Commenting on the findings, Prof. Alexander Woll, of the Institute of Sports and Science at the Karlsruhe Institute of Technology, says:
"The results of our study reveal how important it is to acquire health-promoting habits at early adult age already. This should also be in the focus of prevention measures."
The researchers note that they were surprised to find no direct relationship between physical fitness and health itself when measuring participants' body mass index (BMI), waist-hip ratio, blood pressure, cholesterol and uric acid.
They say this finding could be due to the fact that the fitness test used in the study did not take endurance into account, and this is a factor that can largely impact health.
But they point out that previous research has shown that changes to physical fitness also influence risk factors relevant to health. The research team concludes that they plan to further investigate these results to better determine how health and fitness behaviors impact future health.
Last year, Medical News Today reported on a study suggesting that even if a person does not become physically active until later in life, their health will still see benefits.