The purpose of this study is to understand more about why young people who were born prematurely may have increased risk of high blood pressure and lower cardiovascular exercise capacity.

Young adults with a history of preterm birth are identified as having a unique risk profile for developing hypertension and having reduced exercise capacity. Globally, there are 15 million annual preterm births. In Europe, incidence is 6-15% of all births, with up to 6 million adults in the United Kingdom having a preterm birth history. Understanding the associations between early life exposures and this early cardiovascular risk is extremely important to be able to target primary prevention strategies.

As yet there are no clear explanations for the reduced exercise capacity and elevated risk of hypertension reported in preterm born young adults. Magnetic resonance imaging studies of young adult born premature demonstrated altered heart shape, with increased left ventricular mass, reduced cavity sizes and reduced stroke volumes. The changes in cardiac size identified from these studies is similar to those seen in other disease groups and has been equated to greater than 50% increased risk of cardiovascular clinical events in these groups. These structural changes may account for the reduced exercise capacity observed in preterm born young adults

This study aims to understand the physiological determinants of limited exercise capacity and associated cardiovascular risk profile of adult preterm born populations.

Inclusion Criteria:

• Participant is willing and able to give informed consent for participation in the study.
• Male or Female, aged 18 to 40 years.
• History of preterm birth, diagnosis of hypertension or full term birth normotensive control
• Able (in the investigator's opinion) and willing to comply with all study requirements.
• Participant is freely able to access John Radcliffe Hospital for study visits

Exclusion Criteria:

• Aged <18 years >40 years
• Unwilling or unable to give informed consent for participation in the study.
• Pregnant or lactating during the course of the study.
• Planning to donate blood during the study duration.
• Any significant disease or disorder which, in the opinion of the investigator, might influence the participant's ability to participate in the study.
• Contraindication to Magnetic Resonance Imaging

Adults aged between 18 and 40 years old, recruited from the local community and Oxford University Hospitals Hypertension clinic, participants will have a history of preterm (<37 weeks) or full term (>37 weeks) birth.