One option for cardiovascular exercise is arm cycling, which allows for a great workout without having to use your lower body.
Set an exercise pace that feels good to you. Rate your level of exertion by the Rate of Perceived Exertion scale (range of 6 to 20 where 6 = very, very light, and 20 = very, very hard); 11 to 14 is a good target zone.
Take slow, deep breaths and 'think tall' in order to maintain good posture.
Vary the cardiovascular workout by using a number of different machines, depending on the function of the affected limbs. If you have some muscle control in the affected upper limb, use a hand splint to row or pull. Foot straps can help to hold a spastic lower limb in place.
General cardiovascular exercise should be performed 3-5 days per week for 20 to 60 minutes per session, using shorter intervals of work as needed. If necessary, perform these sessions under the guidance of a physician or exercise physiologist.
If you have decreased sensation in the affected side, shift your sitting position every 10 to 15 minutes to increase circulation and prevent pressure sores.