Accumulating just one to two minutes a day of high-intensity weight-bearing physical exercise is associated with better bone health in women, found a University of Exeter and University of Leicester study.
A single minute of exercise each day is linked to better bone health in women, new research shows. Scientists from the University of Exeter and the University of Leicester found those who did “brief bursts” of high-intensity, weight-bearing activity equivalent to a medium-paced run for pre-menopausal women, or a slow jog for post-menopausal women, had better bone health.
Using data from UK Biobank, the researchers found that women who on average did 60-120 seconds of high-intensity, weight-bearing activity per day had 4% better bone health than those who did less than a minute.
“We don’t yet know whether it’s better to accumulate this small amount of exercise in bits throughout each day or all at once, and also whether a slightly longer bout of exercise on one or two days per week is just as good as 1-2 minutes a day,” said lead author Dr Victoria Stiles, of the University of Exeter. “But there’s a clear link between this kind of high-intensity, weight-bearing exercise and better bone health in women.
“Because this is a cross-sectional study – which assesses data taken from a subset of the population at a particular point in time – we can’t be sure whether the high-intensity physical activity led to better bone health, or whether those with better bone health do more of this exercise. “However, it seems likely that just 1-2 minutes of running a day is good for bone health.”
The researchers looked at data on more than 2,500 women, and compared activity levels (measured by wrist-worn monitors) with bone health (measured by an ultrasound scan of heel bone). As well as finding 4% better bone health among women who did one to two minutes of high-intensity, weight-bearing exercise, they found 6% better bone health among those who did more than two minutes a day.
Stiles said data from UK Biobank – taken from monitors worn for a week – was broken down into single seconds to understand how people go about their daily activities. “We wanted to make every second count in our analysis, because short snippets of high-intensity activity are more beneficial to bone health than longer, continuous periods,” she said.
“We were careful not to ignore short bursts of activity throughout the day.”
As a suggestion for anyone interested in increasing their day-to-day levels of activity, Stiles said: “The UK’s National Osteoporosis Society recommends increasing your walking activity first. Further on, we would suggest adding a few running steps to the walk, a bit like you might if you were running to catch a bus.”
Good bone health has multiple health benefits, including a reduced risk of osteoporosis and fractures in older age.
Background: Physical inactivity is a highly modifiable risk factor for the development of osteoporosis but, due to a lack of research that has precisely and objectively meaured physical activity (PA) relevant to bone, the specific contribution that PA can make to bone health is poorly understood. This study examined whether a more precise measure of PA relelvant to bone was associated with meaures of bone health in pre- and post-menopausal women in UK Biobank.
Methods: Time spent at intensities specific to bone health [≥750 milli-gravitational units (mg) and ≥1000 mg] were analysed from raw tri-axial acceleration data averaged over 1-second epochs from 7-day monitoring of habitual PA using accelerometry-based activity monitors (100 Hz; AX3, Axivity, UK) of 1218 pre- and 1316 post-menopausal healthy women. In a cross-sectional analysis, associations between categories of time (<1, 1–2 and ≥2 minutes) spent above the intensity thresholds and calcaneal quantitative ultrasound measures of bone health (bone mineral density T-score, BMDT-score; speed of sound, SOS; and broadband ultrasound attenuation, BUA) were examined.
Results: Compared with <1 minute, spending 1–2 or ≥2 minutes/day at intensities ≥1000 mg in pre-menopausal and ≥750 mg in post-menopausal women was positively associated with BMDT-score, SOS and BUA.
Conclusion: Brief bursts of high-intensity PA relevant to bone health can be captured by applying bone-specific thresholds of intensity to raw tri-axial accelerations averaged over 1-second epochs. Accumulating 1–2 minutes/day of high-intensity PA, equivalent to running in pre-menopausal women and slow jogging in post-menopausal women, is associated with better bone health.
Victoria H Stiles, Brad S Metcalf, Karen M Knapp, Alex V Rowlands