As long as you stay relaxed and not tense all over, you're less likely to get sick. But what about you? You just can't seem to let go because many things are weighing on your mind. You worry all day long, keeping yourself tightly wound and unable to loosen up. When the sky falls, let it fall—don't worry about it. Just take action, go out and get some sunshine. In fact, 90% of illnesses can be cured on their own. The happier you are, the stronger your immune system becomes.