The vital capacity of our lungs is essential to our health; especially as we get older. Vital capacity (VC) is not the total capacity of our lungs, but rather the total amount of air we can inhale once we have fully exhaled. Everybody has a different VC. It depends on a person’s height, gender, ethnicity, socio-economic status, aerobic conditioning (how physically active a person has been) and their overall health.

Lung function changes as we age. It increases to a maximum around the age of 20 for women and 25 for men. It then stabilises until 35, after which it starts to decline. The total lung capacity remains much the same but our residual volume, the amount of air in our lungs after a full exhalation, increases significantly, which decreases our vital capacity (amount of air we can breathe in).

By the time we reach our 50s and beyond, our rib cage becomes more elevated, our ribs more horizontal and costal cartilage stiffer, which all reduce expansion. We get stuck in the “inhalation” position, unable to lower the ribs during exhalation as much as we once could. Added to this the diaphragm, the muscle of respiration, becomes less elastic and weaker. It doesn’t allow as much passive reduction in chest volume on exhalation. As tissues become stiffer, exhalation is neither as natural nor as passive as before; more work is needed to fully exhale. It also affects inhalation. More work is needed to inhale, in order to overcome the stiffness. Balancing this is a decrease in the lungs’ elasticity, which makes it easier for them to fill with each inhalation but reduces their recoil on exhalation.

As we age and the rib cage becomes more elevated, exhalation takes more work and we must rely upon the weakened diaphragm rather than the elasticity of the rib cage to exhale. The result is that more air remains at the base of lungs, reducing our vital capacity (amount we can breathe in) as we grow older. We find it increasingly difficult to fully exhale all that we inhale.

The challenge, as we grow older, is not to increase the amount we inhale but to increase the amount we can exhale. Practicing reducing your rib cage size with each exhale may help to maintain some of the natural elasticity between the ribs. This can be practiced during yoga classes or at home.

Try these following breathing exercises to help with your vital capacity. (If you have breathing problems, check with a medical practitioner before trying.)

1. Sitting comfortably place one hand on the sides of your lower ribs and the other on your sternum. As you inhale deeply, notice how the lower ribs move out to the side and your sternum lifts. This expansion of the rib cage creates more volume in the lungs, allowing a deeper inhalation. Now slowly exhale, forcing the sternum down and the lower ribs in (engage your abdominal/respiratory muscles). Try and maximise these movements as much as you can several times. Stop if you feel dizzy.
2. Sitting comfortably and take several deep breaths (five-six) through your nose, focusing on the exhale as you completely empty your lungs by drawing your lower ribs in as much as you can (engaging your abdominal/respiratory muscles). If you feel dizzy or light-headed, stop.
3. Sitting comfortably, breath in for six and out for six slowly through your nose. It doesn’t have to be deep. Practice for about a minute and slowly increase the count as you feel more comfortable and confident.

Breathing exercises in yoga classes are known as pranayama practice. You will often practice ujjayi breath, alternate nasal breathing (nadi shodhana, also known as anuloma viloma) which encourage full chest expansion and long slow exhalations.