The effect of interrupting sitting with regular active breaks on vascular function in adults with type 1 diabetes

This study is looking for volunteers aged between 18 and 66 years old who have had type 1 diabetes for at least three years. It's important that you are currently using a specific type of insulin pump system that automatically adjusts your insulin.

We are particularly interested in people who don't currently do the recommended amount of physical activity and who generally spend more than five hours a day sitting or lying down.

Unfortunately, you wouldn't be able to join if you are pregnant, planning to become pregnant, or have recently given birth or stopped breastfeeding. We also can't include people who have a history of certain heart or brain health problems, or those who have had very high or very low blood sugar levels recently that caused problems.

If you join the study, you'll visit a university laboratory twice. Each visit will last about 7 hours and will be spaced at least four days apart. The order of what you do during these visits will be chosen randomly – so you won't know which one you're doing first.

In one visit, you'll sit for the entire 7 hours. In the other, you'll take a short 3-minute walk every half hour. Before each visit, you'll wear a small activity tracker for two days and record your meals using a free app. You'll also be given specific meals to eat the night before and the morning of your visit. You'll continue to use your own blood sugar monitor and insulin pump as usual.

During the lab visits, we'll check your health in a few ways: we'll use ultrasound scans to look at your blood vessels and brain blood flow, take your blood pressure and heart rate, and collect blood samples to look for signs of inflammation. We'll also keep track of your blood sugar levels and insulin use using your own devices. After each visit, you'll wear the activity tracker for another two days and continue to record your meals and blood sugar levels.