People all the time tell me that when you workout with weights you are not doing any Cardio. I call shenanigans ('deceit or trickery') because that is untrue! Next time you decide to workout, trust me when I say that you will get Cardio/Heart exercise while also tiring out your muscles because of your workout.
Pick 3 or 4 exercises and only do 1 set of each, giving yourself 25-30 seconds of rest between each different exercise set. After you have done all 3 or 4 exercises once, do 50 jumping jacks then rest for a minute or so. Do this routine 4 or 5 times for your workout (should take about 40-50 minutes) and you will be breathing very heavily. That will also mean that you are getting cardiorespiratory exercise and a stellar heart workout.