And the winner is... tai chi!

A new study finds the slow, rhythmic Chinese exercises can help seniors beat depression--even in cases where drugs have failed.

Researchers studied 73 seniors with an average age of 70 who had already tried the drug Lexapro, but were still scoring high on depression tests.

Some were randomly assigned to tai chi classes, while the others were put into an equal number of ordinary health classes that included 10 minutes of plain old stretching.

After 10 weeks, 94 percent of the tai chi patients showed major improvement.

Those who took the classes didn't do so bad either--77 percent of them also improved.

What's more, 65 percent of the tai chi group went into complete remission-- versus 51 percent of those who took the health classes.

Remember, these are people who already failed on a powerful drug--yet they're thriving with tai chi and, in many cases, even ordinary health classes and simple stretching.

In addition to having the higher success rate, tai chi came with other benefits: The patients who stuck with weekly two-hour tai chi classes also had improvements in physical function and lower levels of inflammation.

They even did better on cognitive tests, according to the study in The American Journal of Geriatric Psychiatry.

But don't wait for depression drugs to fail to get started. Don't even wait for depression to hit, since other studies have found plenty of benefits that stretch far beyond beating the blues.

Tai chi and the similar exercises of qigong can improve physical function, lower your risk of falling, boost your balance, increase your cardiorespiratory fitness and even give your overall quality of life a lift. (Read more about its benefits here.)

One study found that an hour of tai chi twice a week can help bring significant relief from osteoarthritis pain.

Another study even found it can beat the endless pain of fibromyalgia better than any med.

The best part of all? It's easy to do--and often free or inexpensive. You can even learn yourself, online, by watching the instructional videos available on YouTube and elsewhere.

But since socialization can also help beat depression and lower the risk of cognitive decline, I'd suggest getting outside and joining a tai chi group-- chances are, there's one in your town or senior center.

And if there isn't, maybe it's time to start one.