Sara Lazar, a neuroscientist at Mass General Hospital and Harvard Medical School was training for a marathon when an injury pushed her into physical therapy. Her prescription was to go and stretch. In turn, she started practicing yoga and noticed a number of benefits. Being calmer, more open minded and compassionate were some of the benefits that Lazar cited from doing yoga.
Lazar was doing her PhD in molecular biology at this point, and started doing research on meditation for her post-doc. Lazar started with examining people who currently meditate. The first discovery she made was that long-term meditators have more gray matter in the frontal cortex as well as the sensory regions of the brain. In other words, enhanced senses, a better working memory and decision making.
The next group that Lazar looked at was people who've never meditated in their life before, but were willing to go through an 8 week meditation program. Among several discoveries, Lazar found that the amygdala, which is the fight or flight mechanism in the brain got smaller. This area is also a source for anxiety, fear and stress. A change like that in the amygdala can be correlated to a reduction in stress levels.
As Lazar points out, mindfulness is an exercise. It helps us handle stress better. Lazar herself has been a meditator for many years and reveals the the amount of meditation she does daily is variable. We get that question a lot at NadaPada, which is: "how much should I meditate?" The answer is really up to you, the meditator. We like to think of meditation as an exercise and while you can't run your perfect run everyday, you do what you can and try and be consistent. Some days you may meditate for 10 minutes, another day 27 minutes. Some day you may choose to get 2 minutes of mindfulness and gratitude. It's your practice so do what works for you. If you're a visual person and would like to see Lazar's TED talk on this topic you can view it here