It doesn't take a genius to see that I'm not exactly the 'cardio guy'. It's true, strength is my passion, and if I could only train one athletic quality, strength would be it. However, it doesn't have to be a choice between one or the other. There is tremendous benefit to including cardio/conditioning to supplement your resistance training regimen.
1. Health Cardiovascular fitness is one of the most important things you can do to safeguard your health, both physical and mental. A whole range of nasty diseases like cancer, diabetes, and even Alzheimers can be a much less likely reality for those with a fit heart. Exercise can also be an important tool for mental health issues like depression and anxiety.
2. Recovery Training itself doesn't make you stronger. Recovering from training is what makes you stronger. A higher level of aerobic fitness will improve your body's ability to circulate blood to all of the tissues in your body that need mending after a tough training session.
3. Faster Workouts If doing anything more than 3 reps leaves you out of breath, then your conditioning is garbage. Conversely, being in good condition means you won't need to rest as long and can get your workout done in a shorter time period.
4. A Happier You Performing cardio releases endorphins. These are brain chemicals that make you feel happy. The benefits on mood don't stop there though. Regularly performing cardio can make you more relaxed and in a better mood in general.
5. Not Dying Yes, I am fully aware that this is the exact same as number 1, but staying alive is important enough to warrant 2 points. Plus people like lists of 5. Try and do something every day that raises your heart rate to the point where you can't talk and you'd have to take a shower afterward. Every day.