You could survive for three weeks without food and three days without water. Three minutes without oxygen would probably kill you.

Fortunately, few of us ever face a situation where there is no oxygen to breathe.

But millions of us do regularly face the problem of getting less oxygen than we should.  We’re not breathing deeply and efficiently for several reasons.

Sixteen to 24 million Americans have chronic obstructive pulmonary diseases (COPD), which includes bronchitis and emphysema. COPD does not include asthma, which another 25 million of us have.

In addition to those diseases, air pollution and smoking afflict millions more. And simply aging plays a role, too, as years of shallow breathing can lead to weak diaphragm muscle tone.

All of these respiratory problems significantly raise the danger of serious results from contracting Covid-19. They also increase the likelihood of pneumonia in regular flu.

You can do something to make your lungs fitter, though—exercise to strengthen your diaphragm.

The diaphragm is a dome of muscles that lies beneath your lungs, just above your liver and stomach. It is the diaphragm that enlarges or squeezes your thoracic cavity to control breathing.

Breathing practice goes beyond merely learning to breathe correctly. It gives the muscles under your lungs a real workout and can markedly improve your lung capacity.  Here are two of the best exercises:

Breathing In

You’ve probably seen an incentive spirometer like the one pictured above. Patients often receive them in the hospital after abdominal surgery. You can buy your own online.

A spirometer helps you train yourself to breath in slowly and fully open your lungs for as much air as possible.

This tool is easy to use, but there is some room for error.

If you pick up the tube and put it in your mouth, then breathe in deeply, you may think you are doing quite well. The plunger bangs right up to the top of the machine with a clang. Congratulations!

Not so fast.  The idea is to reach the top with a slow, steady breath. There’s a smaller tube, and that’s the key to regulating your breath properly.

So, here’s the drill: Training your lungs requires regular practice. Do this every two to three hours during the day.

• Sit straight. Hold the inspirator level.
• Breathe out fully, and then put the tube in your mouth with your lips closing around the end piece.
• Breathe in steadily. Try to keep the smaller ball in the “better” or “best” range. On the Voldyne, that’s the left chamber. It will be hard for most people.
• The plunger in the right chamber will rise as you breathe in. Your goal is to reach the correct level for your age, or better. You can use the slider to mark your highest position and work to improve over time.
• After you’ve breathed in fully, hold your breath for 10 seconds. Keep the tube in your mouth. The ball will sink.
• Finally, loosen your grip on the tube for a bit and finish breathing out.
• That’s one count. Repeat 10-15 times.
• After you are done, make yourself cough three times to help clear your lungs.

Breathing Out

The inspirator will help you pull in a full breath, but the problem with COPD or any congestion is difficulty breathing out.

This next exercise strengthens the diaphragm muscles so you can exhale strongly, too. It is called “loaded” breathing.

• You need a sandbag, or something similar that weighs about 6-7 pounds (3 kg). If you are stronger or larger, 10 pounds will be OK.
• Lie on your back, with a pillow under your head for comfort if you need it.
• Place the sandbag over your diaphragm area, just below your rib cage.
• Breathe normally for a bit and soften the diaphragm.
• Now, breathe in slowly, fully, watch the sandbag rise as you do. Don’t use your stomach muscles to push the bag up. It will rise naturally as you expand your chest cavity to breathe.
• Hold your breath to the count of 4 or longer.
• Breathe out, letting your diaphragm fall. Again, don’t use your stomach muscles to force this. You are training the diaphragm muscle beneath your lungs to do the work.

You can’t change your lung “architecture.” If your lungs have fibers or old scar tissue, that will remain the same. But you can increase lung capacity significantly.

These exercises will help you do that.