Background Interventions for preventing or reducing the development of lifestyle-related disorders should be investigated as these conditions are becoming increasingly prevalent and having large effects on quality of life and life expectancy globally. The aim of this pilot study was to prepare for a full-scale randomised controlled trial by evaluating the short-term changes resulting from a function-based preventive intervention aimed at lifestyle-related disorders on a small group of physically inactive 40-year-old people. Change in objectively measured physical activity, functional capacity according to a risk profile, and goal attainment were main outcomes.MethodsParticipants (n = 27) underwent functional examinations including tests of fitness, strength, mobility, balance, and posture as well as standard medical examinations including weight measures, blood pressure and blood tests and were randomised to two groups. The intervention group (n = 15) received feedback from all the examinations and lifestyle counselling based on a functional profile. The control group (n = 12) received feedback only from the standard medical examination. Follow-up was at 3–4 months. Changes in physical activity measured with accelerometers, functional levels on the functional profile, goal attainment and subjective assessments of health-related quality of life, motivation, function, and physical activity were examined, as were standard medical parameters.ResultsChange in mean time in moderate or more intense physical activity was 9 min higher in the intervention group (95% confidence interval -6.35, 24.51) and change in sedentary time was 42 min lower (-95.24, 11.32). The intervention group showed a higher increase in motivation for change 1.58 on 10-point scale (0.20, 2.97) and indicated more improvement on the functional risk levels concerning fitness (-0.06, 0.90). Correlation between objectively measured and self-assessed physical activity and function increased after the intervention. Most participants in the intervention group achieved some or all of their goals.ConclusionsThis small-scale pilot intervention with functional examinations and lifestyle counselling showed positive tendencies for change in short-term physical activity level. It seemed to lead to better understanding of personal functional capacity and increased motivation for lifestyle changes. Setting and fulfilling meaningful goals for lifestyle-related changes seemed to influence levels on the functional profile in positive directions. Research on larger and more diverse populations will be necessary to better understand the implications of the intervention.Trial registrationClinicalTrials.gov: NCT05535296 first posted on 10/09/2022.