The Effect of High Intensity Interval Training on Cardiovascular Fitness in People With Progressive Multiple Sclerosis.

Inclusion Criteria: * Diagnosed with a progressive form of MS * Aged 18 years or older * Known to members of staff of the MS service NHS Ayrshire \& Arran * Ability to attend Douglas Grant Rehabilitation centre twice a week for eight weeks * EDSS 4-6.0 * Able to cycle on ergometer Exclusion Criteria: * A relapse of symptoms requiring treatment within the past three months. * A respiratory condition that would be exacerbated by high intensity exercise including but not limited to: chronic obstructive pulmonary disorder, uncontrolled or poorly controlled asthma. * Uncontrolled high pressure at screening (\>190/100 mmHg) * Cognitive impairment affecting ability to understand instructions as noted in patient's notes. * Currently engaging in another research trial for their MS or that may affect their physiological or cardiovascular outcomes * Weighing more than 110 kg (weight limit of ergometer) * Any pathology or medical intervention that would preclude high intensity exercise, maximal exertion testing or could attenuate the cardiovascular effect of exercise including but not limited to: unstable angina; diabetes; peripheral vascular disease or intermittent claudication; having a pace maker or medicine pump; surgical clips; having another neurological condition other than MS; and pregnancy. To be established from patient's notes and at screening session. * A serious cardiovascular event in the past year including but not limited to: transient ischaemic attack, cerebrovascular event and myocardial infarction. * Taking any of the following medication: beta blockers; vasodilators; ACE inhibitors; diuretics or any other medication that could cause exercise induced hypotension; hypoglycaemic insulin; metformin or other oral insulin medicine.