Many people are tired simply because they are not interested in anything. Nothing ever moves them deeply. To some people it makes no difference what’s going on or how things go. Their personal concerns are superior even to all the crises of human history.
Nothing makes any real difference to them except their own little worries, their desires, and their hates. They wear themselves out stewing around about a lot of inconsequential things that amount to nothing. So they become tired. They even become sick. The surest way not to become tired is to lose yourself in something in which you have a profound conviction.
A famous statesman who made seven speeches in one day was still boundless in energy.
"Why are you not tired after making seven speeches?" I asked.
"Because," he said, "I believe absolutely in everything I said in those speeches. I am enthusiastic about my convictions."
That's the secret. He was on fire for something. He was pouring himself out, and you never lose energy and vitality in so doing. You only lose energy when life becomes dull in your mind. Your mind gets bored and therefore tired doing nothing. You don't have to be tired. Get interested in something. Get absolutely enthralled in something. Throw yourself into it with abandon. Get out of yourself. Be somebody.
Do something. Don't sit around moaning about things, reading the papers, and saying, "Why don't they do something?" The man who is out doing something isn't tired. If you're not getting into good causes, no wonder you're tired. You're disintegrating. You're deteriorating. You're dying on the vine. The more you lose yourself in something bigger than yourself, the more energy you will have. You won't have time to think about yourself and get bogged down in your emotional difficulties.
Norman Vincent Peale, The Power of Positive Thinking