Hourly movement breaks of just 5 minutes each seem to offer the best balance between feasibility and effectiveness for mitigating the health harms of prolonged sitting, suggests a large study carried out under real world conditions and published online in the British Journal of Sports Medicine.
These brief interludes boost mood, lessen fatigue, and don't undermine work performance, the findings indicate, prompting the researchers to suggest this approach offers potential for a public health strategy and inclusion in physical activity guidelines.
On average, adults in high-income countries are sedentary for 11–12 hours during the day—a level of inactivity that has emerged as a significant public health concern, associated with heightened risks of many long term conditions and death, note the researchers.
Laboratory studies suggest that brief movement breaks are a promising option for offsetting the health harms of prolonged sitting, but it's not clear if they are feasible in the real world, or what the optimal frequency might be.
To find out, the researchers drew on 19,342 adults taking part in the interactive 'Body Electric Challenge' organised by National Public Radio (NPR) in the US. Participants spanned a wide range of ages, occupations, and work environments.
Nearly 60% (11,484) of participants took 5-minute walking breaks at their self-selected break frequency of either 30 (6108; 32%), 60 (9116; 47%), or 120 minutes (4118; just over 21%) for 14 days straight, preceded by 7 days of their usual routine.
Most participants received a daily email survey at 20:00 hours throughout the 21 day period to assess changes in fatigue, mood, and work performance. But a random sample of 1200 full-time employees received five SMS-based daily surveys at 09:00, 12:00, 15:00, 18:00 and 21:00 hours to assess the immediate impact of movement breaks.
Implementation potential was assessed using the Feasibility, Acceptability and Appropriateness of Intervention Measures (FIM, AIM, IAM), each consisting of 4 items on a 5-point scale. A score of more than 3 was considered positive.
Analysis of the survey results showed that all three break frequencies were rated as feasible, acceptable, and appropriate, scoring above 3, and indicating implementation potential.
Feasibility was higher at lower break frequencies, while acceptability and appropriateness were high across all three.
Reported fatigue and low mood fell while reported good mood increased significantly across all three break frequencies, with improvements showing a dose-response pattern.
The 30 and 60 minute break frequencies exceeded minimally important difference (MID) thresholds for fatigue and good mood, while only the 30 minute break frequency exceeded this threshold for low mood.
MID thresholds represent the smallest change that patients/participants perceive as genuinely helpful or harmful. They are used to ensure that research results are truly meaningful to participants, rather than just reflecting statistical significance.
Hourly movement breaks offered the best balance between feasibility and effectiveness.
While the 120-minute frequency showed the strongest implementation potential, it was the least effective, and although the 30-minute frequency produced the strongest improvements in fatigue and mood, it scored low on feasibility and compliance, explain the researchers.
"The 60-minute arm offered the most favourable balance, yielding acceptability and appropriateness ratings comparable to the 120-minute arm, and exceeding MID thresholds for two of three psychosocial outcomes. In addition, it was the most commonly selected dose, selected by nearly half of all participants," they write.
Taking short breaks didn't affect work performance, the survey results indicated.
"Concerns that movement breaks might disrupt work productivity have been documented as a perceived barrier to implementation/adoption. However, our findings counter this perception," say the researchers.
"While none of the tested movement break doses elicited improvements in perceived work performance or engagement that exceeded MID thresholds, all yielded small but favourable changes, on average (4%–7% for engagement; 1–3% for performance)," they add.
The researchers acknowledge several limitations to their findings: all outcomes were subjectively assessed, so prone to inaccuracy; participants were mostly White, female, and highly educated, so the findings may not be more widely applicable; and the study length was short, making it difficult to know how sustainable the approach would be over the long term.
Despite these caveats, the researchers conclude: "This large-scale study demonstrates that movement breaks are implementable and effective, supporting their potential as a public health strategy and providing new insights into feasible and effective dosing for real-world implementation that can be integrated into existing guidelines and tested in future trials."
