Things That Put Strain on Your Heart

   –  Sitting still for long periods of time every day, your blood does not flow as effectively as if you were active, your heart has to pump harder
   –  Caffeine products speed up heart
   –  Stress makes heart beat faster
   –  Fat will contribute to clogging of arteries, making it harder for heart to pump blood through body
   –  Some forms of medication will put stress on heart
   –  High alcohol consumption can lead to high blood pressure, which is bad for heart
   –  Too much salt causes you to hold onto (retain) water, increases swelling in your legs, and makes it more difficult for your heart to pump

Supporting evidence
for "sitting still for long periods" search google, "boy died from pulmonary embolism from playing video games"

This list goes hand in hand with these other lists:
Rules for A Healthy Lifestyle
Avoiding Lower Back Pain Guide
Keeping Your Digestion System Healthy