There is a relationship between aerobic fitness and survival both with and without surgery. Some patients can improve their aerobic fitness with a structured exercise programme but currently it is not know how much this could change predicted survival for patients with an abdominal aortic aneurysm, or how long this change can be maintained. Survival can be predicted after planned abdominal aortic aneurysm (AAA) surgery using physical fitness measured with a cardiopulmonary exercise test. The researchers have validated this in a published peer reviewed multicentre study. In this study the patient's fitness will be measured before and after a structured exercise programme and assess if there is any change in their predicted survival. The primary objective of the study is to measure the change in predicted survival for abdominal aortic aneurysm surgery after a structured exercise programme. In addition the patients are asked to complete the following questionnaires:- EQ-5D-5L, Hospital Anxiety and Depression Scale (HADS) before and after the exercise programme.

The UK has a national AAA screening programme. At the age of 65 men are offered a one off ultrasound test to look for a AAA. If their abdominal aorta is > 5.5 cm they are referred to a Vascular Surgeon. If the patients abdominal aorta is between 3 cm and 5.4 cm they are offered further ultrasound scans to monitor the size of their aorta. This is a surveillance programme. In addition men who have an AAA between 3 cm and 5.4 cm that is detected by an ultrasound scan, CT or MRI performed as part of an investigation for another clinical problem are added to the surveillance programme.

In Torbay and South Devon men in the AAA surveillance programme are referred for a Cardiopulmonary Exercise Test when the AAA reaches 4.5 cm as part of standard clinical practice. This takes place in the Pre assessment Clinic in Torbay Hospital and is performed by a Consultant Anaesthetist. If the patient is able to safely perform the Cardiopulmonary Exercise Test they will be identified as potential participants by the Consultant Anaesthetist.

Inclusion Criteria:

1. Male participants ≥ 18
2. Under surveillance as part of the AAA screening or surveillance programme with an AAA that is between 4.5 cm and 5.4 cm
3. Able and willing to provide informed consent
4. Understand verbal and written instructions in English
5. Able to safely perform a cardiopulmonary exercise test (this will confirm they can use a cycle ergometer)
6. Patients who are already participating (or have participated) in other trials may be eligible, but the relevant trial teams must agree this in advance.-

Exclusion Criteria:

1. Contra-indications to exercise (lower limb amputation without prosthesis, bone, joint or muscle problem which may be exacerbated by exercise, chronic lung disease causing desaturation with exercise or shortness of breath at rest, severe psychiatric health problems)
2. Cardiovascular contra-indications (unstable angina, acute left ventricular failure, uncontrolled cardiac arrhythmias, uncontrolled hypertension, cardiac event in the previous 6 weeks, cerebral vascular accident in the previous 6 weeks)
3. Participation in other treatment trials, where this has not been agreed in advance with both trial teams
4. Symptomatic AAA
5. Urgency of surgery for AAA precludes undertaking exercise programme. -