Abstract 15859: Interrupting Prolonged Sitting Reduces Resting Blood Pressure and Plasma Norepinephrine in Adults With Type 2 Diabetes

Abstract

Interrupting prolonged sitting with frequent short bouts of light-intensity physical activity reduces blood pressure (BP) in overweight, non-diabetic adults, however, the effects in adults with type 2 diabetes (T2D) have not been investigated. This study examined the effects of two types of activity breaks (light-intensity walking or simple resistance activities) compared to continuous, uninterrupted sitting on resting BP and plasma norepinephrine (NE) in adults with T2D. In a randomized crossover trial, 24 inactive adults with T2D (14 male; 62 ± 6 y; BMI 33.0 ± 3.4 kg/m 2 ) consumed standardized breakfast and lunch meals during 3 x 8 h conditions (6-day washout): i) SIT: uninterrupted sitting (control); ii) LW: sitting + 3 min bouts of Light-intensity Walking (3.2 km/h every 30 min); and iii) SRA: sitting + 3 min bouts of Simple Resistance Activities (half-squats, calf raises, gluteal contractions and knee raises) every 30 min. Resting seated BP was measured hourly (mean of 3 recordings, performed ≥ 25 min after activity). Venous blood was drawn every 30 min for the plasma NE assay, ≥ 25 min after activity. As illustrated in figures 1A and 1B, compared to SIT, both LW and SRA reduced BP ( P < 0.001); with the effect being more pronounced with SRA ( P < 0.01 vs. LW). Similarly, compared to SIT, both LW and SRA reduced plasma NE concentrations, with SRA significantly lower than LW ( P < 0.01). In conclusion, simple interruptions to sitting lowered resting BP and plasma NE concentration in adults with T2D. Reduced sympathetic vasoconstrictor tone may contribute to the observed hypotensive effect. With the ubiquity of sedentary behaviours and the low adherence to structured exercise, this approach is a practical strategy which may contribute to BP control.