What can you do for your health each day that won’t take much time or cost you much (if anything) but will help you feel better almost instantly?

No, if you guessed some over-the-counter something, you’re off. Nice try, though. This one’s even easier.

If you’ve heard or read anything about the power of being grateful, you know that expressing gratitude can help you feel happier. But did you know that daily attention to gratitude also helps you become healthier?

Feeling grateful wards off illness in your body, mind and soul. (All of those matter if you want to be completely well.) People who feel thankful have overall better health, experience fewer physical symptoms, have more energy, exercise more and have larger social networks. They sleep better, longer and more soundly, and they wake up more refreshed.

Practicing gratitude can even increase your ability to resist viral infections, help you reduce stress hormone levels, improve the functioning of your immune system and help you live longer (along with happier). In one study, people who became more appreciative of life after a heart attack had a reduced incidence of a second attack.

That’s a huge list of wins for such as simple practice. You don’t have to spend hours, and you really don’t have to spend a dime. The only thing you may have to do is keep reminding yourself to focus more on gratitude vs. complaining.

Even if you’re the human equivalent of Oscar the Grouch, you can learn to become a beacon of optimism. Only about half of your mood is determined by your genetic disposition. The rest stems from what you choose to focus and work on.

So, what do you choose? It’s in your hands.