Born Early, Moving Less: Norwegian Wearable Study Links Preterm Birth to Lower Physical Activity

People born preterm appear to carry a subtle but measurable disadvantage in physical activity that persists well into adolescence and adulthood, according to a large Norwegian study that tracked participants’ movements with wearable sensors for a full week. The research, published in PLOS One, linked birth records from Norway’s Medical Birth Registry with activity data from the Trøndelag Health Study, known as the HUNT Study, creating one of the most detailed pictures yet of how gestational age shapes movement patterns across the lifespan.

The study’s strength lies in its design. Rather than relying on questionnaires, which are notoriously prone to recall bias and overestimation of exercise, the researchers used objective device-based measurements of physical activity. Participants wore accelerometers for seven consecutive days, allowing the team to capture not just formal exercise but the full spectrum of daily movement, from walking to work to fidgeting at a desk. This objective approach matters because self-reported activity data can obscure exactly the kind of modest differences the study was designed to detect.

By linking individual birth records with later health survey data, the researchers could compare activity levels across the full range of gestational ages, from very preterm births to full-term deliveries. The analysis accounted for a range of potential confounding factors, aiming to isolate the effect of being born early from other circumstances that might influence a person’s activity habits, such as family background, socioeconomic conditions, and health status in adulthood.

The central finding was consistent: the earlier the gestational age at birth, the lower the device-measured physical activity in adolescence and adulthood. People born very preterm moved less overall than those born at term, and the pattern held across age groups studied. The differences were not dramatic on an individual level, but across entire populations they could translate into meaningful public health consequences, given how strongly physical inactivity is linked to cardiovascular disease, type 2 diabetes, obesity, and premature mortality.

Why would preterm birth leave such a long shadow on movement behavior? The researchers point to several plausible mechanisms. Preterm infants are at elevated risk of complications that can affect motor development, including bronchopulmonary dysplasia, a chronic lung condition common among babies born extremely early, as well as cerebral palsy and other neurodevelopmental disorders in the most severe cases. Even among preterm children without diagnosed disabilities, subtle differences in motor coordination, muscle strength, and cardiorespiratory fitness have been documented in follow-up studies, and any of these could make physical activity feel more effortful or less rewarding.

There may also be behavioral and social pathways at work. Children who struggle with sports and playground games early in life may gradually disengage from physical activity, a process that compounds over the years as exercise habits crystallize. Parents of children born preterm, meanwhile, may be more protective or cautious about physical exertion, shaping the child’s activity environment from the start. The Norwegian data cannot definitively separate these mechanisms, but the persistence of the association into adulthood suggests that whatever drives it is not simply a transient feature of childhood recovery.

The study draws its power from the HUNT Study, one of the largest population-based health surveys in the world, which has followed residents of Trøndelag county in central Norway across multiple generations since the 1980s. By combining HUNT’s accelerometer measurements with the Medical Birth Registry’s prospectively recorded gestational age data, the researchers avoided the recall problems that plague retrospective studies of birth outcomes. Gestational age in the registry is based on clinical assessment at the time of birth, not on participants’ memories decades later.

The findings arrive at a moment of growing international concern about the long-term health of preterm survivors. Thanks to advances in neonatal intensive care, the vast majority of babies born preterm now survive into adulthood, and cohorts of preterm-born individuals are larger than at any point in history. Research consortia such as RECAP Preterm, funded through the European Union’s Horizon 2020 program, which also supported this study, have been assembled specifically to pool data across countries and understand how preterm birth reshapes adult health risks, from cardiometabolic disease to mental health and, now, physical activity.

For clinicians and public health planners, the study suggests that physical activity promotion could be a valuable and underused tool in the long-term follow-up of preterm-born populations. If preterm survivors are systematically less active, they may accrue less of the protective benefit that exercise provides against the very diseases, such as hypertension and insulin resistance, to which they are already predisposed. Targeted interventions, whether through pediatric follow-up programs, school physical education, or adult primary care, could help close this gap before it compounds into elevated disease risk.

The authors note that the observed differences in activity were modest at the individual level, and that many people born preterm are highly active and healthy. The association describes a population-level trend, not a destiny for any individual. Still, in a field where early-life origins of adult disease have become a central research theme, the study adds a new dimension: the legacy of preterm birth may extend not only to disease risk but to the everyday behaviors that shape health across the entire life course. As wearable sensor technology becomes routine in population health research, studies like this one are likely to keep refining our understanding of how the earliest weeks of life echo through decades of movement, metabolism, and well-being.

Subject of Research: The long-term association between preterm birth and device-measured physical activity levels in adolescents and adults

Article Title: People born preterm are likely to be less physically active as teenagers and adults, according to large Norwegian study which measured a week of participants' activity using wearable sensors

Article References: People born preterm are likely to be less physically active as teenagers and adults, according to large Norwegian study which measured a week of participants' activity using wearable sensors. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: preterm birth, physical activity, wearable sensors, HUNT Study, Medical Birth Registry, gestational age, PLOS One, Norway, accelerometry, neonatal outcomes, lifelong health, exercise behavior