This study aimed to examine the longitudinal associations of maternal body mass index (BMI), weight status in childhood and late adulthood and device‐measured total physical activity (TPA) in older age.

The study involves 552 participants from Helsinki Birth Cohort Study who were born in Helsinki, Finland in 1934–1944. TPA was measured with a multisensory body monitor at a mean age of 70 years and expressed in metabolic equivalent of task‐hours/day (METh/d). Childhood overweight (BMI >85th percentile) was based on school health records at 6‐7 years of age and late adulthood overweight (BMI ≥25 kg/m2) was based on clinical measurements at the mean age of 61 years.

Childhood overweight was associated with lower TPA, particularly in older women (mean difference ‐3.2 METh/d, 95% confidence interval (CI) ‐4.6– ‐1.9), and late adulthood overweight was associated with lower TPA both in older women (mean difference ‐6.2, 95% CI (‐7.2– ‐5.1) and in older men (mean difference ‐2.6 METh/d, 95% CI ‐3.7 – ‐1.5). TPA in older age was highest in participants who were normal weight both in childhood and adulthood and lowest in participants who were overweight in childhood and adulthood. In participants with childhood overweight, TPA was lower in participants who were overweight in childhood and adulthood, compared to those who were overweight only in childhood. There was a U‐shaped distribution of TPA according to maternal BMI in older women (p=0.002), but not in older men.

In conclusion, reaching normal weight after childhood predicted higher physical activity levels in older age.