Good hydration can be really beneficial for deep tissue massage making the massage more effective, it is especially important to be fully hydrated before the massage.
When your being massaged and the tight and adhesive tissue fibres are being broken down, this in turn releases trapped metabolic waste from the muscle and increases blood flow to the area.
This is where being hydrated is really important, increased blood-flow carries oxygen and nutrients to the muscle helping to repair it. If your well hydrated the rate at which this happens is much faster as the oxygen and nutrients are carried in the water in your blood, this also means that as the nutrients and oxygen pass into the muscle fibers the metabolic waste product is being flushed out and is carried away by the water to your lymphatic system, where it is excreted from your body.
Therefore you will feel the benefit of your massage much quicker if you are well hydrated!!