Children with obesity who displayed more dynamic physical activity patterns — characterised by frequent transitions between movements and less prolonged sedentary time — had lower body fat percentage and better measures of insulin sensitivity than peers with more sedentary profiles, according to a cross‑sectional analysis published from the PODiaCar project in Milan.
Study design and key findings
Researchers analysed data from 91 children and adolescents with obesity (mean age 11.2 years; 43% girls). Participants wore thigh‑mounted accelerometers for seven days to record detailed movement patterns. Using a machine‑learning approach called discriminative dimensionality reduction via learning a tree, investigators identified three distinct behavioural phenotypes based on activity volume, intensity distribution, accumulation of sedentary time, temporal fragmentation and transitions between activities.
- Sedentary Pattern: observed in 24% of participants
- Light Activity Pattern: observed in 55%
- Higher Activity Pattern: observed in 21%
Children in the Higher Activity Pattern recorded less sedentary time and more time in light, moderate and moderate‑to‑vigorous activity than those in the Sedentary Pattern. Notably, only 3 participants met the World Health Organization recommendation for moderate‑to‑vigorous physical activity.
Metabolic measures
Outcome measures included body composition (fat mass percentage and fat‑free mass percentage) and metabolic markers such as fasting glucose, fasting insulin, the Single Point Insulin Sensitivity Estimator (SPISE) and a cardiometabolic risk z‑score.
| Phenotype | Proportion of cohort | Fat mass % (example) | Fat‑free mass % (example) |
|---|---|---|---|
| Sedentary Pattern | 24% | higher (reference) | lower (reference) |
| Light Activity Pattern | 55% | intermediate | intermediate |
| Higher Activity Pattern | 21% | 38.8% | 61.2% |
Compared with the Sedentary Pattern, children in the Higher Activity Pattern had a significantly lower fat mass percentage (38.8%) and higher fat‑free mass percentage (61.2%), with P values below .05. The SPISE index, which estimates insulin sensitivity, was significantly higher in the Higher Activity Pattern versus the Sedentary Pattern (mean difference 0.90; P = .016). The cardiometabolic risk z‑score was also lower for the Higher Activity Pattern compared with the Sedentary Pattern (mean difference −0.42; P = .017).
What this means for clinicians and caregivers
The findings suggest that not only the total amount of activity but the patterning of movement across the day — more frequent transitions and less continuous sedentary time — may be associated with more favourable body composition and insulin sensitivity among children with obesity. The low number of participants meeting WHO moderate‑to‑vigorous activity targets emphasises the challenge of achieving recommended activity levels in this population.
These results are based on a relatively small, cross‑sectional sample from a single project and cannot establish causation. Nonetheless, they add to evidence that interrupting prolonged sedentary behaviour and encouraging varied, regular movement can be beneficial for metabolic health in children with obesity.
Practical advice
- Encourage frequent short breaks from sitting during the day, especially in children who spend prolonged time seated at school or home.
- Promote a mix of light and moderate activities across daily routines rather than relying solely on isolated structured exercise sessions.
- Healthcare practitioners should discuss movement patterns with families and consider referrals to community or school programmes that increase daily activity.
Readers are reminded that individual health decisions should be made with a clinician. Families concerned about a child’s weight or metabolic risk should consult their local clinic or paediatrician rather than self‑diagnose.
