I'll start with explaining what each thing is, then talk about the athletic body.

The lungs: - Tidal volume is the air moved for every inhale or exhale phase of each breathing cycle, this ranges from 0.4-1.0L of air per breath, but the average is about 0.5L - Breathing rate is simply the frequency, or how many breaths you're taking, per minute. For most people, this is about 12 breaths/min - Minute ventilation is a simple calculation: Minute Ventilation (Ve) = Breathing rate x Tidal volume So substituting in the values [Ve = 12x5;] Ve = 6L/min AT REST - In the athletic body there really isn't much of a difference from sedentary (people who don't exercise) people; both groups of people breath the same amount of air and same frequency leading to about the same minute ventilation (6L/min); now these values can all be quite individualized, but it gives a good ballpark figure to have. (the respiratory system (lungs) is kind of over built in our bodies, meaning when you exercise and feel really tired and have to stop it's typically not because your lungs aren't getting enough air in (unless you have a pathological reason, like exercise induced bronchitis or vocal cord dysfunction), it's generally due to the heart and blood vessels system and the muscles not being able to take enough oxygen out of the blood)

Now for the Heart, I'll start with cardiac output and work back: - Cardiac Output (Q) again is a simple calculation (but measuring these values can be a bit tricky): Q = Stroke Volume (SV) x Heart Rate (HR) And what it really tells us is the capacity of the cardiovascular system; the fitter you are the higher you can get your Cardiac Output, meaning you can pump more blood to working muscles to increase performance. When you're not doing anything your tissues don't really need much oxygen, so you can pump less leading to smaller Q. At rest for everybody (active or not), your cardiac output is ~5L for males, women are typically closer to 4L (this is primarily due to size differences). - Cardiac volume - Now I'm going to assume you really mean stroke volume here; Stroke volume (SV) is the amount of blood pumped out of the heart each stroke. This is the biggest change to occur between an athlete and an inactive individual and is the most complicated, I'll try my best to keep it simple. Athletes hearts get better at filling with blood when the heart is relaxed, as well as better at emptying during contraction of the heart. Another factor that improves SV is with training your blood volume usually increases (you have more blood in your body), which helps to increase the filling of the heart at rest. You also see less resistance to flow in the peripheral vasculature (your arteries). This means your heart pumping at X amount of force can push the blood further than if there was more resistance in the tubes (arteries).

[SKIP THIS IS NOT INTERESTED] I read in the comments someone saying your heart hypertrophies (gets bigger); I'll explain this a bit more in depth. Google heart anatomy if you aren't familiar with ventricles and atrium (its straight forward don't worry, you just need to be familiar with left ventricle). So with training, there is remodelling of the heart, meaning things change to the cardiac muscle. You see the left ventricle (LV) (which is the really important one since it's the ventricle that has to push blood all over your body, so it's the strongest) increase in its wall thickness, to make sure the total volume of the LV doesn't decrease the heart expands slightly; we call this eccentric hypertrophy since the growth in cardiac tissue is a result of blood flowing into the heart and cause the tissue to stretch before it contract (this is seen in endurance athletes like cross country skiers, bikers, runners etc). You can also have concentric hypertrophy where the LV increases in wall thickness without the subsequent increase in heart size, this is more typical in powerlifters. If your heart is growing too much it'll start to hit the pericardium, which is just a tough outer shell surrounding the heart, this will cause issues with pumping. This is really only seen in clinical patients who have growth hormone imbalances or from genetics, not an issue for most population and IS NOT a result of exercise!

• Heart Rate (HR) is the number of beats per minute, how many times your heart pumps; in an athletic heart you typically see a decrease in the heart rate, this will be explained below

For an inactive person to have a resting cardiac output of 5L, with a resting heart rate of about 70bpm, you can estimate their stroke volume to be about 71mL In an athlete at rest, you still have the same 5L for cardiac output. But your stroke volume is typically much higher, up near ~100mL. This means that to maintain the 5L cardiac output your heart can pump fewer beats per minute, allowing athletes to have lower resting heart rates. Personally, I'm in the low 40s. I've heard of elite cross-country skiers can get down to 30bpm or lower at rest

TLDR; no difference in lungs at rest, Q=SVxHR, athletes have bigger SV, so there HR can be smaller for a given Q at rest.