John Ratey is a famous Harvard psychiatrist who wrote Driven to Distraction. In Spark: The Revolutionary New Science of Exercise and the Brain (http://www.amazon.com/Spark-Revolutionary-Science-Exercise-B...), he explains how intense aerobic exercise, like sprints or interval training, will generate the fuel that grows your brain and makes you smarter, and puts your brain chemicals in balance to improve learning esp if you have a history of partying, stress, anxiety, etc.
I have been running several miles a day for a few months, and then last week I started running sprints and noticed an immediate effect.
This is the routine I've been doing: I've been running in a field about the size of a soccer field. To start off I jog half the soccer field and then on the second lap I sprint the length of the field (about 50 yards) and then jog the remaining part. Then walk a lap to catch my breath. So one interval is three laps -- one jog, one jog/sprint, one walk -- at first I did that 4 times, and then increased it to 5, 6, 7, as you get better. When you sprint, just pump your arms and run as fast as you can. Do that 3 times a week -- every other day to let your brain and body recover. On off days, jog a few miles. He gives more details in the book.
A great deal of what you're saying (and many more) is explained there.
John Ratey (http://en.wikipedia.org/wiki/John_Ratey), the professor of psychiatry at Harvard Medical School who wrote Driven to Distration, recently published a book called Spark: The Revolutionary New Science of Exercise and the Brain (http://www.amazon.com/Spark-Revolutionary-Science-Exercise-B...).
Spark details how high-intensity cardio (like sprints or interval training) put your brain chemicals in balance in part by generating BDNF (http://en.wikipedia.org/wiki/Brain-derived_neurotrophic_fact...), which as Ratey describes, it's like "Miracle-gro" for the brain.
Last year my stress levels were getting out of control from working too much. At the time I was running at least two miles every day so it's not like I wasn't exercising. But then one day I changed from running a couple miles to running 50-yard sprints, as fast and as hard as I could push myself. The first day I only ran four sprints, but I felt euphoric the rest of the day -- the best I had felt in years. So I tried it again a couple days later, and sure enough it worked again -- I felt amazing.
So then I had to find out why this worked -- why a few sprints were so much more effective than running several miles. I started Googling and eventually found Ratey's book -- it explains the entire biochemical process of what's going on and why sprinting works.
It's an eye-opening read. Each chapter covers how high-intensity cardio affects things like stress, anxiety, depression, ADHD. I have ADHD but haven't taken anything for it in years (since I was in college), and I can attest that sprints not only fixed by stress levels, but my ADHD symptoms were almost non existent.
Here's a key point that Ratey makes throughout the book that completely changed my perspective on things -- he says that instead of thinking of exercise as something you should do to look good and build a healthy body, you should instead think of exercise as the key to building a healthy brain:
"We all know that exercise makes us feel better, but most of us have no idea why. We assume it’s because we’re burning off stress or reducing muscle tension or boosting endorphins, and we leave it at that. But the real reason we feel so good when we get our blood pumping is that it makes the brain function at its best" (http://www.sparkinglife.org).
In the book's introduction he goes on to say, "Building muscles and conditioning the heart and lungs are essentially side effects. I often tell my patients that the point of exercise is to build and condition the brain."
In fact the brain exercise routine he recommends is similar to a weight workout routine, in that you have to push yourself hard one day, and then take a day off to let your brain recover, just like in weight training. Another key is when you sprint, always put everything you have into it. Run as fast and as hard as you can so you are constantly pushing your body and your brain past their limitations -- this is the key to growth.