While the number of men with gym memberships has increased 16 percent since 2003, the number who hit the weights has dropped by an alarming 15 percent. Why alarming? Because lifting weights three days a week can…

1. Cut your risk of diabetes in just four months, according to a Tufts University study. Weight training decreases blood-glucose levels and improves insulin sensitivity.

2. Treat depression, according to Harvard researchers who compared the benefits of weight training and cardio exercise over 10 weeks. The lifters experienced a greater mood boost.

3. Spike your testosterone levels by up to 49 percent, according to Finnish scientists. The hormone plays a key role in your overall mortality risk and, of course, your sex drive.

4. Save your brain from a stroke, according to a University of Michigan study. Lifting weights decreases blood pressure, reducing the risk of a stroke by 40 percent.