In spite of advances in neonatal intensive care allowing the first generation survivors of extreme prematurity to now reach young adulthood, these individuals present with reduced exercise capacity; a strong predictor of later chronic disease and mortality. The reason why individuals born preterm have exercise limitation remains unclear and may be a consequence of impact of preterm birth and associated neonatal difficulties on the development of organs important for exercise, namely the lungs, the heart, the vessels (which bring blood and oxygen to the muscles) and the muscles. It is well known that exercise benefits overall health in at-risk as well diseased populations. However, whether exercise training can improve fitness in young adults born preterm was not demonstrated and whether the cardiovascular, pulmonary and muscle impairments associated with preterm birth are reversible through exercise intervention in young adulthood is unknown.

The investigators postulate that a 14-week exercise intervention will improve exercise capacity in preterm adults, as seen in other at-risk populations, in correlation with measures of vascular health, heart and muscle perfusion and oxygenation, and pulmonary function detected by cutting edge and highly sensitive imaging and circulating biomarkers. These markers are more sensitive to pre-disease changes than traditional health measures, and are largely unexplored in preterm populations.

The investigators will:

1. Determine whether a 14-week supervised exercise training improves exercise capacity in young adults (18-29 years old) born very preterm at <29 weeks gestational age.
2. Examine whether improvement in exercise capacity is associated with changes in (a) markers of vascular health including circulating endothelial progenitor cells and microparticles, (b) cardiac perfusion by cutting-edge oxygenation-sensitive cardiovascular magnetic resonance imaging (MRI), (c) lung regional ventilation measured by newly developed hydrogen proton (1H) MRI, (d) muscle oxygenation during exercise.
3. Compare the response of the above measures to exercise intervention between young adults born very preterm and term controls.

Inclusion Criteria:

Both groups :

• Aged between 18-29 years old
• Less than 120 minutes of exercise per week
• Willingness to be part of the 14 weeks exercise intervention

Preterm group:

- Born under 29 weeks of gestation

Term group :

• Born between 37-41 weeks
• Appropriate weight fo gestational weight

Exclusion Criteria:

• Pregnancy
• conditions excludins individual from exercise