For the last couple years all my training has been almost nothing but lifting. The occasional sparring match has been my only cardio. Now I'm getting ready to reenlist in the Army and am having a lot of trouble getting my running times down where they need to be. I can run 1 mile in 7:30 without much trouble, but when I run further than a mile my heart and lungs can't seem to keep up. Any suggestions for ways to improve cardio other than running? I'm already runnin every evenin before supper but I'm not progressing fast enough. Thanks for any help.