We can't breathe in the past or breathe in the future, we can only breathe right now. This is why we use the breath to bring us into the present moment. Why is it so important to anchor ourselves in the now? Because it keeps us sane. We are all born with a basic sanity but we cloud it with thoughts. And rather than identifying with our sanity, we identify with our thoughts. The Buddha called our thoughts, monkey mind. The first stage of meditation is to tame the monkey. If we don't tame the monkey, we are not in control, our monkey is in control, and we don't want our life led by a monkey!
In the East, heart and mind are one word. Whereever our heart is, that is where our mind is. If ice cream has its hooks in us, our mind and body may be at the computer working but our heart is eating ice cream. Our heart may also be worrying or thinking about the future or going over something that made us unhappy in the past. But we only have control over the now. The now is what creates our future so it's best to focus on now.
This split between our heart and mind - even if it's just an ice cream split - is what causes anxiety and stress. This doesn't mean we always need to have our heart in the now but we need to be in control of our mind. If we want to stop thinking about ice cream and we can't then we know that our monkey is in control.
There's a Buddhist story about a poor man who found a large sack of barley. He put the barley in a sack, tied it to a rafter in his house, lay down beneath it and began to fantasise about how the barley would make him rich and once he was rich, he would get married and have children. However, all this time, a rat had been gnawing at the rope that was holding up the sack. The rope suddenly snapped and the sack fell on the man and he was killed.
This is not a cheerful story but it's a stark reminder. Dreaming about the past and future is a distraction. The home of our heart is in the here and now. Only when wer're home can we be truly happy. Shaolin monks use the practice of Qigong and Kung Fu to tame their monkey mind and bring them into the present moment. Once our monkey mind is tamed, we access our natural sanity and happiness spontaneously arises. This is good news. It means we're in control. We're not seeking something external to make us happy. We realise that true happiness comes from within. Once our monkey mind is tame, we can then begin to train it.