Pilates exercises are traditionally not considered cardiovascular because the body will rarely experience breathlessness during the exercises. However, with muscle loading, the circulatory and oxygen demand within the working muscles causes the body to require deeper breaths and increased breathing rate. Therefore the harder the exercise and the larger the muscles being worked, the higher the oxygen demand is. You will find that certain exercises can encourage some slight increases in breathing rate and therefore, small amounts of increased cardiovascular fitness. It is important to continue walking/ running/ swimming/ cycling etc to maintain or improve cardiovascular fitness.