I get asked this question a lot "Do you need both weight training and cardio?". Many people have been told that while weight training increases strength and muscle mass it is not a replacement for cardiovascular exercise such as jogging, swimming, bicycling, etc.
The truth is that a proper weight training program will increase strength & muscle size, enhance flexability and yes it will even improve cardiovascular fitness. No other form of exercise can give you all of those benefits, not running, spinning or any of the others.
Now of course if you rest five minutes between sets you will not get much cardiovascular benefit, but if you are taking short rests between sets, or even no rest between sets by doing supersets, tri sets, giant sets or circuit training you can get all exercise benefits at once.
This will also save you time because you won't have to first do your weight lifting workout then go for a long run.
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