Mixed sitting interruption reduced plasma renin activity compared to control, standing, or walking, but no significant effect on arterial stiffness or sympathorenal activation was observed.
Do sedentary behavior interruptions reduce sympathorenal activation and mitigate arterial stiffness in adults?
Interrupting prolonged sitting with standing or walking did not significantly improve arterial stiffness or sympathorenal activation compared to uninterrupted sitting over a 4-hour period.
Absolute Event Rate: 0% vs 0%
SYMPATHORENAL CONTRIBUTIONS UNDERLYING THE PROPOSED CARDIOVASCULAR BENEFITS OF SEDENTARY BEHAVIOR INTERRUPTION Sai Satvik Kolla1, Jeb F Struder1, Alexander Pomeroy1, Kristen M Paternoster1, Christopher E Grice1, Andrew M Koessler1, Taylor Shorter1, Craig Paterson1,2, Gaurav Dave1, Bethanny B Gibbs3, Feng-Chang Lin1, Michelle L Meyer1, Maihan B Vu1, and Erik D Hanson, FACSM1 1 University of North Carolina, Chapel Hill, NC, USA 27599 2 University of Bristol, Bristol, UK, BS8 2PS 3 West Virginia University, Morgantown, WV, USA 260506 BACKGROUND: Only 24% of U.S. adults meet federal physical activity guidelines, yet public health recommendations remain limited. Prolonged sedentary behavior (SB), an understudied contributor to cardiovascular disease, elicits a sympathorenal response that promotes arterial stiffness (AS). Evidence suggests that SB interruptions (SBI) benefit arterial elasticity, but the mechanistic basis remains unclear. Therefore, we hypothesized that SBI participation would attenuate sympathorenal activation, thereby mitigating AS. METHODS: 36 adults (79%F, age: 45.7 ± 7.9 y, BMI: 27.9 ± 5.5 kg·m⁻²) were included in this preliminary analysis composed of 4 visits where 4 hours of uninterrupted (CON) or interrupted (standing, STAND; walking, WALK; combination, MIXED) sitting bouts were completed. After 20 min of semi-recumbent rest, carotid-femoral pulse wave velocity (cfPWV) was assessed via cuff-based oscillometry, followed by blood sample collection before and after each condition. Linear mixed models and mediation analyses were used to investigate SBI-specific responses in cfPWV, plasma renin activity (PRA), plasma epinephrine (EPI), and serum aldosterone (ALD). All outcomes were natural-log transformed to improve model fit and residual normality; p ≤ 0.05. RESULTS: Nonsignificant time-by-condition interactions were observed for cfPWV (p = 0.503), PRA (p = 0.518), EPI (p = 0.253), and ALD (p = 0.265) between SBI and Control. Indirect SBI–cfPWV mediation was not observed for EPI (β = −4.02 × 10⁻⁵ ± 0.00104, p = 0.969), PRA (β = −0.00210 ± 0.00167, p = 0.208), or ALD (β = −0.00104 ± 0.00270, p = 0.700), contributing to 1.96%, 72.0%, and 37.6% of the total effect, respectively. PRA significantly differed between SBI conditions, with lower PRA reported during MIXED compared to CON, STAND, or WALK conditions (≤ −0.25 ± 0.09 ng·mL⁻¹·hr⁻¹, p ≤ 0.034). EPI was unrelated to cfPWV (β = −0.01960 ± 0.01508, p = 0.194), whereas both PRA (β = 0.0293 ± 0.00877, 95% CI 0.0126–0.0469, p DISCUSSION: Contrary to our hypothesis, sympathorenal activation did not differ between SBI and CON, and cfPWV was similar across conditions. PRA did significantly differ between MIXED compared to CON, STAND, and WALK, and biological plausibility between PRA/ALD and cfPWV prediction was apparent: a 1% increase in PRA corresponded to a 0.029% increase in cfPWV, and a 1% increase in ALD corresponded to a 0.064% increase in cfPWV, suggesting that Renin-Angiotensin-Aldosterone system (RAAS) activation may result in AS presentation. Future investigations should explore how adaptations in SBI implementation may impact this mechanistic association. FUNDING SOURCE: This research was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number R01HL157187.
Sai Satvik Kolla (Sun,) reported a other. Mixed sitting interruption reduced plasma renin activity compared to control, standing, or walking, but no significant effect on arterial stiffness or sympathorenal activation was observed.