Happiness is a skill, emotional balance is a skill, compassion and altruism are skills, and like any skill they need to be developed. That's what education is about.
If we dedicate a certain amount of time each day to cultivating compassion or any other positive quality, we are likely to attain results, just like when we train the body... Meditation consists of familiarizing ourselves with a new way of being, of managing our thoughts and the way we perceive the world. Through the recent advances in neuroscience it is now possible to evaluate these methods and to verify their impact on the brain and body.
There is definitely openness to others' suffering that is dealt not with distress but with compassion.
Wisdom and compassion should become the dominating influences that guide our thoughts , our words, and our actions.
When you engage in compassion, and you hear a distressing sound, like someone calling for help, there is an activation in an area of the brain called the insular, which has to do with empathy and altruism, that is vastly more activated than in non-meditators.
Meditation is about cultivating constructive emotions, like altruism, compassion.