Patterns of physical activity over 34 years in a large sample of adults: The HUNT study, Norway.

To examine physical activity patterns over 34 years in a representative adult population in Norway. Longitudinal data were obtained from the Helseundersøkelsen i Trøndelag (HUNT) study, performed in 1984-1986 (HUNT1), 2006-2008 (HUNT3) and 2017-2019 (HUNT4). There were a total 123,005 participants across all four studies. Physical activity patterns over time are described, in relation to age, gender and body mass index (BMI). Multiple imputation was used to handle missing data. The proportion of adults estimated (using a proxy measure) as being physically active 1 h or more per week increased from 32% in 1984-1986 (HUNT1) to 64% in 2017-2019 (HUNT4). The most frequent pattern was being inactive at HUNT1, becoming active at HUNT3 and staying active (until HUNT4). From HUNT3 to HUNT4, the most frequent pattern was being active at both time points. The adults >50 years old had a similar physical activity pattern from HUNT3 to HUNT4 and were more active than those >50 years. During the period, men were more active than woman, but difference was reduced over time. Both for persons being underweight (BMI ⩽ 18.5) or obese (BMI > 30), the proportion being active at multiple time points was lower than for persons at normal weight.