News · Fitness & Exercise
University students sat more and moved less than people in their 70s, in smart-ring data from 1,967 adults
Physical activity is supposed to fall with age. Four weeks of smart-ring data from three age groups in Singapore turned that around: the students were the least active and the most sedentary.
- An observational study of 1,967 adults in Singapore: 500 students, 437 working-age adults and 1,030 older adults.
- Each wore a smart ring for four weeks, recording activity, sitting and sleep around the clock.
- Students sat for about 10.5 hours a day and moved least; older adults sat least and moved most.
- Swapping 30 minutes of sitting for other behaviors went with a slightly lower BMI and waist-related measure.
- Volunteers for a tech study may not represent everyone, and the swaps are estimates, not tested changes.
The usual story about activity across a lifetime is simple. Young people move the most, working adults sit at desks, and older people slow down as illness and frailty set in. Public health campaigns have been built around it, with older adults as the group most in need of getting off the sofa.
A study in BMC Medicine checked that story with four weeks of smart-ring data from 1,967 people in Singapore. It came out upside down: university students sat the most and moved the least, while people in their 70s moved the most.
Why movement across the whole day matters
MedlinePlus is plain about the stakes: regular exercise is one of the best things you can do for your health, with benefits that include reducing your risk for many chronic diseases. Sitting for long periods and sleeping too little add their own risks.
The authors note that although older adults are traditionally expected to be less active and more sedentary than young adults, contemporary social, occupational and educational environments may have changed this. Unlike most studies, which count exercise alone, this one looked at activity, sitting and sleep together across the full 24 hours, which gives a more complete picture of a day.
How the smart-ring study measured three age groups
Data were analyzed from 1,967 adults across three Singaporean cohorts: 500 university students averaging about 20, 437 working-age adults averaging about 41, and 1,030 older adults averaging about 74. Each person contributed four weeks of recordings from a smart ring worn on the finger, tracking time spent active, sitting and asleep.
The researchers also measured body mass index, a measure of body roundness, and artery stiffness, and asked how shifting time between behaviors related to those markers of heart and metabolic health.
What the rings showed about student movement
The students were the outliers. University students accumulated the most SB and the lowest PA and sleep, sitting for about 10.5 hours a day. Older adults accumulated the least SB and greatest PA and sleep, sitting for about 8.3 hours, with working-age adults in between.
The health markers pointed the same way. In the statistical models, reallocating 30 minutes per day from SB to other behaviors was associated with lower BMI and a lower body roundness score, and moving time into activity or sleep was linked to similar small improvements.
Why young adults may be the overlooked group
Most efforts to get people moving target middle-aged and older adults. The authors conclude these findings challenge conventional expectations about age-related inactivity and highlight young adulthood as a critical, under-recognized target for interventions.
Habits formed in early adulthood tend to carry forward, and the heart and metabolic effects of long sitting build over decades. If students are this sedentary, the years when patterns are set may be passing with little attention.
What volunteer wearable data cannot show
The authors list the limits. The findings are derived from convenience samples of individuals who volunteered for a consumer-technology tracking study, who may not represent the wider population. The older group was restricted to one ethnic group by design, and income and other social factors could not be fully accounted for.
The time-swap estimates are statistical scenarios, which the authors say should be interpreted as hypothetical associations. They do not show what would happen if a student actually swapped 30 minutes of sitting for a walk, and the differences in BMI linked to those swaps were small.
What this changes for student activity
For young adults, the message is that inactivity is not a problem saved for later life. Breaking up long stretches of study or screen time, walking more, and protecting sleep are worth building in now.
For universities and public health planners, the study suggests students deserve the same attention as older adults in efforts to get people moving. The design of campuses, timetables and study spaces may matter as much as any exercise campaign.
People also ask
What did the study find?
University students accumulated the most sedentary time (about 634 minutes a day) and the least physical activity (320 minutes) and sleep (432 minutes), while older adults had the least sedentary time (501 minutes) and the most activity (420 minutes) and sleep (456 minutes). Reallocating 30 minutes a day from sitting to other behaviors was associated with 0.28 lower BMI.
What counted as physical activity?
Any movement above rest recorded by the ring, from light activity such as walking around the house to vigorous exercise. That is why the daily totals are large.
What is sedentary behavior?
Time spent sitting or lying down while awake, such as studying, desk work, commuting or watching screens.
What does reallocating time mean?
A statistical way of asking what a day would look like if 30 minutes were moved from one behavior to another, since the day has a fixed 24 hours. It estimates associations; it does not show what would happen if someone actually changed.
Why would students be so inactive?
The study did not test reasons. Long hours of study, screens and campus life are plausible contributors, and older adults in Singapore may walk and move more in daily routines.
What should young adults take from this?
That the habits linked to heart and metabolic health start early. Breaking up long sitting and adding movement and sleep are reasonable goals at any age. This is general information rather than medical advice.