The answer to this is: BOTH
One of the most common questions about exercise is this: Should I be doing cardio or weight training exercises?
The answer to this is: BOTH.
Cardiovascular training enhances your body’s ability to utilize oxygen, while weight training enhances your body’s ability to activate muscles (basically becoming stronger). Excelling at one does not necessarily mean you will be efficient in both. Just doing one form of exercise exclusively will prevent you from developing a balanced physique and cause you to lose out on the health benefits of both. Of course, something is better than nothing, so even if you can’t fit both in on a regular basis, do what you can!
But isn’t cardio better for weight loss since it burns more calories?
Cardio burns more calories throughout a workout than lifting weights does. This means that, most of the time, you will burn more calories doing 30 minutes of cardio than you would doing 30 minutes of weight training (this depends, of course, on the intensity of your workout). However, an important distinction lies in what happens after your workout. About 10 minutes after you have finished your cardio workout your body is no longer burning extra calories. On the other hand, a weight training workout will continue to burn calories throughout the entire day as your body rebuilds the small tears in your muscles (this is a good thing!).
So, if you only have 15 minutes or so and must pick one, go with weight-training. It’ll rev up your metabolism for the rest of the day, essentially giving you more bang for your buck.