Since I’ve been doing regular brain exercise, I’ve noticed an interesting correlation between brain training and my happiness or sense of well-being. If I’m feeling happy and relaxed, I do better at the brain exercise; and when I do the brain exercise, it makes me feel happier and more relaxed. And it seems that I am not alone – comments on this crop up regularly from other brain trainers.

Recent scientific research would seem to shed light on both aspects of this phenomenon. Beginning with research performed by Dr. Richard Davidson at the University of Wisconsin in 2005, scientists have consistently found that the brains of those who meditate (such as Tibetan monks in Davidson’s study) function differently than normal brains. The firing of neurons is better coordinated and more intense.

On a much more limited, short term scale, this reflects my experience when I am feeling tranquil and at peace during brain training. I can improve my attention further if I close my eyes and breathe deeply between training blocks. The end result is better attention to the exercise and a greater ability to complete the training successfully. On days when I’m feeling stressed or low, my brain can’t stay focused and retaining items in working-memory is a struggle.

The longer we work on these skills of mindful meditation, the studies found, the greater the effect.

Scientific studies also provide insight into the second phenomenon – that brain training makes us feel happier. Scientists have discovered that new neural growth is essential if antidepressants are to work effectively. Researchers from UT Southwestern showed that when they inhibited the growth of new nerve cells in an area of the brain called the dentate gyrus, it inhibited the operation of antidepressants. In a separate study, German researchers showed that chronic stress inhibits new neural cell growth, leading to a greater risk of depression.

Which brings us back to brain exercise. Two activities are known to stimulate new nerve cell growth in the dentate gyrus: aerobic exercise and working-memory activation. While we’ve known for decades that aerobic exercise benefits us for many reasons, the finding that brain exercise can not only help keep us sharp but can also help keep us chipper is a welcome discovery.

It’s important to note that not all brain exercises produce these benefits to any significant degree. Casual brain teasers or games that don’t demand our full focus and attention over an extended period will likely not be much use. The conditions for new nerve cell growth call for intense concentration at a novel and rewarding mental task.

If you’re looking for a brain training program, you should see what the vendor says about the training method. Is it based on hard science with proven results? Are the improvements you should expect well defined? Avoid products that make only vague or general references to these things, and those that don’t provide a schedule for the product’s use.

As with any form of exercise, brain exercise rewards in equal measure to our investment. We can’t expect to stay physically fit without breaking a sweat – so, too, a truly effective brain training program requires our attention and effort. The rewards to our mental health and happiness, however, can repay every ounce of that investment.