Arnold Schwarzenegger Out for Bike Ride 2 Months After Heart Surgery

Arnold Schwarzenegger's back, as promised, and looking happy and heart-healthy enough to go for a bike ride.

The 70-year-old actor hit a Santa Monica bike path Thursday and was seen pedaling around with a friend ... less than 2 months after having emergency open-heart surgery.

We broke the story ... Arnold had to have the emergency operation after a scheduled valve replacement repair went awry.