If you're considering training programs to keep your lungs and heart fit and keep yourself lean, jogging/cardio may seem like a good choice (especially for burning fats), however I suggest you consider also these options: interval training and PACE (which seems related). Saves a lot of time and may earn similar or better results.
It's about short training sessions with high-intensity, until you pant and can't continue, with rests for your pulse to calm down (default is 120 bpm), very popular in track-and-field athletics. For example 8 series of 60 or 100 or 200 m runs at very high pace.
Surprisingly at first sight, you may improve your shape more and reduce fat by such short trainings more than running 1 h a day at 10 km/h. PACE is similar, but less demanding, usually less series and you can do any activity, just it should push your pulse and breathing up to the limit, depending on your physical condition at the moment.
According to the research presented in PACE, long-distance running may damage your heart and induce wreckage in the cardiac muscle-tissue (in general there are more marathon runners dead of a heart-attack, than sprinters). To cope with long runs, your body may adapt by reducing pulmonary capacity and making the heart working more efficiently, reducing its energy consumption and maximum power output, and reducing overall muscle mass.
On the other hand, pushing your muscles, lungs and heart to the limit makes them to adapt by extending their capacity, like stretching does - you should stretch until you feel tension/a bit of hurt, otherwise you won't extend your stretching range. Alike, moderate intensity continuous exercises are supportive.
I realized I've got my own practical version of interval training/PACE - some activities I like doing when I could, including high intensity in short durations. I suppose it could explain some phenomenons I've been confused of, such as one two years ago: why on a Silent Disco party I could dance and "jump around" at high intensity for hours in the winter - i.e. no cycling for many months; not practiced any crosses/long runs since a decade?; haven't been on any similar dance session since many months. I was working in an office, sometimes walking (usually at fast pace).
The answer could be just "youth" or "genes", but people around me were also young, even younger than me, and I bet they were going to parties many times more often than me, but they couldn't keep my pace at all. No, I didn't have any alcohol or energy drink - just water.
Finally one of the organizers came to cheer me and he said "could you please stop, it's very nice that you've been dancing so hard, but there's another party tomorrow, we have to leave..."
How could you train your heart and lungs easily (my suggestion):
- Run the stairs (yes: run). Don't use the elevator, unless you're very tired already or you live in a skyscraper.
- Practice cycling. It could be short distances (5-10-15 km), but take some hills, do sprints to get breathless - up to 25-30-35-40 km/h - it will force you to take a rest. Don't ride all the time at 18 km/h.
- Carry your bike through stairs.
- When you dance, do some intensive sessions to get out of breath and to have to rest; then dance again - don't shake slowly all the time.
- On a stepper or a stationary bike - ride to the maximum (after a warm-up) to get tired and breathless - you'll be done in a few series in minutes.
- Rope jumping is also fun if you could practice it, and it could increase your pulse instantly.
You could also:
- Watch your pulse in rest and in the sessions.
- Watch the max rate you achieve (but of course, be careful with this and approach step-by-step) .
- How quickly your pulse can go from rest up to 150/180/X/Max and back down? The faster/wider the dynamics, the better trained is your heart.
- Portable devices to check the capacity of your lungs.
Check these for yourself for more info:
http://www.pacerevolution.com/ - "PACE - The 12-minute fitness revolution"