Acute cardiometabolic effects of interrupting sitting with resistance exercise breaks

Interrupting prolonged sitting with light activity breaks, such as short walks, improves cardiometabolic outcomes, yet less is known about the impact of resistance exercise breaks. This study examined the effects of hourly, guidelines-based simple resistance exercise breaks on acute cardiometabolic health outcomes over a simulated work period. Fourteen adults (age: 53.4 ± 9.5 years, body mass index: 30.9 ± 4.8 kg/m²) completed 2 randomized 4-h conditions: prolonged sitting (SIT) and hourly resistance exercise breaks (REX). Glucose, triglycerides, blood pressure, and heart rate were measured at baseline and then hourly. Pulse wave velocity (PWV) was measured before and after each condition. Linear mixed models evaluated overall condition effects and differences at each hour. Cohen's d estimated magnitude of effects. Four-hour glucose area under the curve (AUC) did not differ by condition (REX vs. SIT: β = -0.35 mmol/L, p = 0.278, d = 0.51). However, an attenuation of postprandial glucose at 1 h (β = -0.69 mg/dL, p = 0.004, d = 1.02) in REX compared with SIT was observed. Triglyceride AUC, mean blood pressure, and PWV did not differ significantly between REX and SIT overall or any time point (all p > 0.05). Heart rate was higher across the experimental period in REX versus SIT (β = 3.3 bpm, p < 0.001, d = 0.35) and individual time points (β ≥ 3.2 bpm, p ≤ 0.044, d ≥ 0.34). Resistance exercise breaks can potentially improve 1-h postprandial glucose, but may not acutely benefit other cardiometabolic outcomes. Future studies employing guidelines-based resistance exercises to interrupt prolonged sitting with a larger sample and longer follow-up are warranted.