Prolonged Sitting

The goal of this clinical trial is to examine the effects of interrupting prolonged sitting with different standing intervals on vascular health in healthy women aged 18-45 years. The main questions it aims to answer are: Does interrupting prolonged sitting with short standing intervals (10 minutes every hour) improve blood pressure and pulse wave velocity more than prolonged continuous standing intervals (30 minutes every hour)? Does interrupting prolonged sitting with prolonged intermittent standing intervals (30 minutes every hour divided into three 10-minute standing bouts) improve blood pressure and pulse wave velocity more than prolonged continuous standing intervals (30 minutes every hour)? The researcher will compare three different sitting interruption conditions to evaluate their effects on vascular health outcomes: Standing for 10 minutes every hour. Continuous standing for 30 minutes every hour. Intermittent standing for 30 minutes every hour divided into three 10-minute standing bouts. Participants will: Attend three experimental sessions in random order separated by at least 7 days. Complete 3 hours of sitting with different standing interruption protocols. Undergo measurements of blood pressure, pulse wave velocity, and heart rate before sitting and after each hour of the experiment. Undergo height, weight, and body mass index measurements.