"Massage can help enhance attentiveness, focus, mental clarity, and emotional balance"
A running joke in the massage world involves "massage brain". Massage brain occurs when someone gets off the massage table and they are so relaxed or sometimes half asleep, they forget to put their shoes on the right feet, leave something in the room, or call the receptionist by their daughter's name. (Don't worry, when we see this happen, we make sure they are all good before we let them drive home.) So despite this initial "fuzziness", massage actually more long-term can have the total opposite effect in that it can help with clarity and focus, and getting the brain in a good place.
How? Lots of ways. First starting with the obvious - it helps calm down stress. When the body is stressed, it releases cortisol and lots of other "fight or flight" hormones, which can definitely focus the brain, but not in the ways we usually need it to focus. Massage can help clear out the cortisol and other stuff to allow the brain to be more clear and focus on what it wants to focus on, rather than what it needs to focus on. Also when someone isn't preoccupied with stress, it opens the mind to more creativity and focus. When the body itself is less stressed, muscles relax and the body is less tense and in pain so it is easier to think and be calm.
Next, massage can release good endorphins and hormones that make the body feel good. When the body feels good, creativity is stimulated and that allows for ideas and decisions to come more easily. There is also more motivation to get stuff done when the body is feeling good, and it is easier to get work done more efficiently. Massage can increase blood flow and improve circulation, getting vital nutrients and oxygen throughout the body more quickly and efficiently. This includes oxygen to the brain, and this helps the brain function better, therefore helping concentration and focus improve.
There is also some research that suggests that the different sides of the brain are affected by emotions and how the body feels. If the body feels tired, fatigued, stressed, or depressed, stress hormones are getting released, and the right side of the brain is more active. If the body is feeling good, upbeat, happy, and good hormones are being released, the left side of the brain is more active, and the left side of the brain is responsible for creativity, memory, and concentration. Massage takes away the bad stuff and stimulates the good stuff, therefore actually influencing the way the brain works.
So while massage may relax you to the point where your brain feels like mush, perhaps that is just a sign that your brain needs to shut down for a bit. After the massage, the brain can come back stronger and more clear than it was previously. Massage truly can help the whole body, as well as the mind.