Meditation is essentially a training camp for the mind. It builds our concentration and focus. It also has a beneficial impact on the rest of our body, both emotionally and physically. As the Dalai Lama mentions in this video, keeping a calm mind is very important because we are not influenced so much by "disturbances". If there is an emotionally wrenching situation, we are more capable to sail through it strongly. If you are exposed to a virus or disease, our bodies are more likely to be immune to them or recover from them.

Listen to this short video straight from the Dalai Lama from Dharamsala, India.
“the benefits of a calm mind”

http://youtu.be/OFn0AX4oZsc