Clint Eastwood is 90 years old and has been practicing transcendental meditation for about 40 years. That might explain why his often high-stress work as an actor and director hasn't taken a toll on his health.

For some time, research has indicated that meditation is linked to a lower risk for cardiovascular disease. But until now, the evidence hasn't been rock-solid.

Recently, researchers from the Cleveland Clinic and elsewhere decided to conduct a closer analysis. Their study, published in the American Journal of Cardiology, involved data on more than 61,000 adults, 6,000 of whom said they regularly practiced some form of meditation.

After controlling for factors such as age and sex, the researchers found that those who meditated were half as likely to suffer from coronary artery disease. The meditation group also had significantly lower rates of diabetes and stroke.

If you're looking to begin meditating, here's a simple exercise: Place your index finger at the base of the pinky finger on your opposite hand.

Breathe in for a count of four while tracing your index finger up to the tip of your pinky, and then breathe out to a count of four to six while you trace back down. Then move on to your ring finger.

Continue until you've traced your whole hand. Then reverse direction and head back toward your pinky.