Lung capacity: normal values by age and sex

The lung capacity of a healthy adult peaks at around 20 to 25 years of age, then the volume of air you can actually move declines slowly for the rest of your life. At 40, the predicted total volume of the lungs is close to 6.9 liters for a man 1.75 m tall (5 ft 9 in) and 5.2 liters for a woman 1.62 m tall (5 ft 4 in). These values depend on age, sex and, above all, height. To decide whether your lung capacity is normal, lung specialists no longer rely on a fixed percentage: they use a limit specific to your profile, calculated from more than 74,000 healthy people.

What is lung capacity?

Strictly speaking, lung capacity means total lung capacity (TLC): all the air in the lungs after a forced breath in. In everyday language, the term also covers the air you can actually move, which doctors call vital capacity. The distinction matters, because part of the air never leaves the lungs: the residual volume, which keeps the alveoli from collapsing. At rest, each breath moves only about half a liter, less than a tenth of TLC.

Pulmonary function tests divide this volume into compartments. Spirometry, the most common test, measures what you can breathe out: forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). TLC and residual volume require body plethysmography, performed in a closed booth, or a gas dilution technique. The table below gives predicted values for the different lung volumes and capacities at age 40, which we calculated with the GLI 2021 equations, built on 7,190 measurements in people of European ancestry aged 5 to 80 (Hall et al., 2021).

A common belief holds that we only use a small part of our lungs. That is true at rest, but exercise draws on the reserve: inspiratory capacity and expiratory reserve volume then act as a buffer. It is precisely this breathing margin that aging erodes, well before any disease appears.

Why lung capacity declines with age

The total volume of the lungs (TLC) stays almost stable throughout adult life: what changes with age is the split between air you can move and air that stays trapped. According to the GLI 2021 equations, the TLC of a 1.75 m man goes from 6.47 liters at 20 to 6.81 liters at 80. His residual volume, however, almost doubles, from 1.37 to 2.69 liters, rising from 21% to 40% of TLC. In a 1.62 m woman, residual volume rises from 1.04 to 2.16 liters (22% then 45% of TLC). Vital capacity shrinks by the same amount.

A review from Geneva University Hospitals describes the mechanisms behind this physiological aging of the lung (Janssens et al., 1999). A synthesis from the University of Texas completes the picture (Sharma and Goodwin, 2006).

• The alveoli widen and the gas exchange surface shrinks. Physiologists speak of “senile emphysema”, an age-related process that is distinct from the emphysema seen in smokers.
• The elastic tissue that holds the small airways open becomes sparser. They close earlier during each breath out and trap air, which inflates the residual volume.
• The chest wall loses flexibility, particularly when the upper spine becomes curved or deformed. Breathing then takes more work.
• The respiratory muscles, led by the diaphragm, lose strength. Coughing becomes less effective at clearing the airways.
• The respiratory centers react less to low oxygen and breathlessness is perceived less clearly, which sometimes delays the diagnosis of a lung disease.

These changes still allow adequate gas exchange at rest and during exercise throughout life, the Geneva authors point out. They do, however, shrink the reserve available during pneumonia, heart failure or an asthma attack. This aging of the respiratory system ties in with cellular senescence, one of the mechanisms of aging that we explain in detail on our pillar page.

Normal lung capacity by age and sex: the reference values

Normal values come from the equations of the Global Lung Function Initiative (GLI), a task force of the European Respiratory Society. The GLI 2012 equations are based on 74,187 healthy non-smokers aged 3 to 95, including 57,395 of European descent, drawn from 72 centers in 33 countries (Quanjer et al., 2012). For each profile, they provide a predicted value, the expected average, and a lower limit of normal (LLN) that corresponds to the 5th percentile. The two tables below, calculated from these equations, follow a 1.75 m man and a 1.62 m woman from age 20 to 80.

Lung function follows three phases: growth until early adulthood, a plateau lasting a few years, then a decline linked to aging (Agusti and Faner, 2019). In our GLI calculations, FEV1 peaks at around 22 in men and 20 in women. The Framingham cohort, which followed 4,391 people for a median of 23 years, confirms that women who never smoked complete their lung growth earlier than men (Kohansal et al., 2009). Between 30 and 70, predicted FEV1 drops by 1.23 liters in a 1.75 m man, or 31 mL per year, and by 1.00 liter in a 1.62 m woman, or 25 mL per year.

Repeated measurements in the same people give similar orders of magnitude. A systematic review of 16 cohorts and 31,099 adults without respiratory disease puts the median FEV1 decline at 22.4 mL per year in studies with more than 10 years of follow-up (Thomas et al., 2019). The absolute decline in that review is faster in men (median 43.5 mL per year) than in women (30.5 mL), but the relative loss is the same. The authors also observe that the decline seems to speed up with each decade.

Height weighs more heavily than age on lung capacity. At 50, a man 1.65 m tall (5 ft 5 in) has a predicted FEV1 of 3.33 liters, compared with 4.29 liters for a man 1.85 m tall (6 ft 1 in). Sex also matters: for the same height of 1.75 m at age 50, the equations give 3.80 liters for a man and 3.23 liters for a woman, a 15% gap. A synthesis from the Politecnico di Milano links this difference to anatomy (LoMauro and Aliverti, 2018). At equal stature, boys have larger lungs and more alveoli. The male trachea has a 29% larger cross-section, the central airways of men remain 14 to 31% wider even at equal lung volume, and their diaphragm is about 9% longer.

Ancestry also enters the calculation of normal values, a point that is now under debate. In 2023, the American Thoracic Society recommended replacing equations specific to each ethnic group with a single equation (Bhakta et al., 2023). This GLI Global equation reanalyzes the same data (Bowerman et al., 2023). For an adult of European descent, it gives predicted values up to 6% lower than GLI 2012, with wider limits of normal. Your test report should normally state which equation was used.

How to interpret your lung capacity on spirometry

A spirometry result is first compared with the lower limit of normal, not with 80% of the predicted value. The 2022 ERS/ATS standard on interpreting lung function tests bases its classification on the limits of the healthy reference population (Stanojevic et al., 2022). The report often expresses the gap as a z-score: 0 corresponds to the average of healthy people with the same profile, and the lower limit sits at -1.645.

When judging results after 60, the 80% threshold becomes misleading. According to our GLI calculations, the lower limit for FEV1 equals 81% of the predicted value at age 20 in men, but 72% at 70 and 69% at 80. A healthy man in his seventies can therefore score 75% with nothing abnormal. In Bergen, Norway, among 71 people over 70 who had never smoked and had no symptoms, about 35% had an FEV1/FVC ratio below 70%, and nearly half did after age 80 (Hardie et al., 2002).

The fixed 0.70 threshold for the FEV1/FVC ratio, still used to define COPD, raises the same problem. An analysis of 57 reference equations and 40,646 adults, 13,136 of them healthy, shows that the lower limit of this ratio falls below 0.70 at around 42 in men and 48 in women (median ages) (Swanney et al., 2008). Applied to entire populations, this threshold produced up to 60% false positives. This debate does not call spirometry itself into question: the World Health Organization points out that a COPD diagnosis must be confirmed by this test.

For a reliable result, the quality of the test matters as much as the equations. After a maximal breath in, you must blow out in one go, as hard as possible, then empty your lungs completely, and repeat until the attempts agree. The 2019 ATS/ERS technical standard sets out these maneuvers and the quality control of the devices (Graham et al., 2019). A lingering cough, phlegm or unusual breathlessness are good reasons to ask for spirometry, even if older results were reassuring. Our article on shortness of breath during exercise helps you tell a lack of fitness from a warning sign, and the one on COPD after 60 explains when to see a doctor.

What lung capacity predicts about your health

Low lung capacity is associated with higher mortality, including in people without any respiratory disease. In Buffalo, in the United States, 1,195 adults aged 20 to 89 were followed for 29 years. Those in the lowest FEV1 quintile had a risk of death multiplied by 2.24 in men and by 1.81 in women, after adjustment for smoking, BMI and blood pressure (Schünemann et al., 2000).

The link between lung function and mortality runs largely through the heart. A meta-analysis of 12 cohorts and 83,880 participants associates a reduced FEV1 with a 1.77-fold risk of cardiovascular death, independently of age, sex and smoking (Sin et al., 2005). In the American ARIC cohort of 7,489 adults, it was mainly forced vital capacity that predicted survival, not airway obstruction (Burney and Hooper, 2011).

These associations do not prove that smaller lungs cause deaths. Burney and Hooper suggest one explanation: difficult growth in the womb is associated with lower vital capacity, with cardiovascular risk and with type 2 diabetes. Research on lung function trajectories adds another nuance. Among 657 adults whose FEV1 was below 80% of predicted before age 40, 26% had COPD 22 years later, compared with 7% of the 2,207 adults who started with a normal FEV1 (Lange et al., 2015). About half of COPD cases came from low lung function to begin with, not from an accelerated decline.

Preserving your lung capacity: the habits that count

Once growth is over, no method has been shown to clearly increase the lung capacity of a healthy adult. The realistic goal is to slow the decline and protect the reserve, which mostly means avoiding whatever speeds it up. The table sums up the effects measured in studies, and the list that follows turns these figures into practical steps.

For the lungs, quitting smoking outweighs everything else by far. In the Lung Health Study, smokers who quit regained an average of 47 mL of FEV1 over the following year, then their decline was cut in half, close to that of non-smokers (Scanlon et al., 2000). In Framingham, quitting was beneficial at any age, with a clearer effect in those who quit early. In France, smoking was still responsible for more than 68,000 premature deaths in 2023. Quitting is the only way to protect yourself, and the World Health Organization stresses that tobacco users need help to quit.

Physical activity plays a more modest role. In Copenhagen, very active smokers lost 4.8 mL less FEV1 per year than smokers with low activity (Garcia-Aymerich et al., 2007). In the ECRHS cohort, active adults had an FEV1 43.6 mL higher, a gap seen mainly in smokers, with no slower decline (Fuertes et al., 2018). Weight mainly affects the reserve volumes: the largest changes already occur with overweight and moderate obesity (Jones and Nzekwu, 2006). As for air pollution, the ESCAPE project links PM10 particles to a lower FEV1, even at current European levels (Adam et al., 2015).

• Stop smoking, whatever your age, with support if you need it. Our article on smoking and the years of life it costs explains what quitting allows you to win back.
• Move every week. The World Health Organization recommends 150 to 300 minutes of moderate-intensity activity per week for adults. Endurance training reduces breathlessness for the same effort, even though it does not enlarge the lungs.
• Keep an eye on your waist size. Abdominal fat hinders the downward movement of the diaphragm and reduces the expiratory reserve.
• Limit what you breathe in: avoid running along roads with heavy traffic, air out your home every day and wear respiratory protection against dust or solvents at work.
• Follow the recommended vaccination schedule after 65, especially the flu shot every fall, because respiratory infections eat into the reserve.
• Ask for spirometry if you smoke or used to smoke, or if a cough, phlegm or breathlessness sets in. A first measurement then serves as a baseline to track your lung function over time.

Breathing exercises, singing or playing a wind instrument help you control your breath better, but none of the studies cited here show that they enlarge the lungs of a healthy adult. A meta-analysis of seven trials in healthy people over 60 shows that inspiratory muscle training, which consists of breathing in against resistance, strengthens maximal inspiratory pressure. Its effect on functional capacity has not been demonstrated (Manifield et al., 2021). To receive our research summaries on how the organs age, subscribe to our newsletter.

Frequently asked questions about lung capacity

What is normal lung capacity for an adult?

At 40, the predicted total volume of the lungs (TLC) is about 6.9 liters for a man 1.75 m tall and 5.2 liters for a woman 1.62 m tall, according to the GLI 2021 equations. The volume you can blow out during a forced effort, the FVC, reaches about 5.1 and 3.7 liters. A result is normal if it is above the lower limit of normal calculated for your age, sex and height.

How do you measure lung capacity?

Spirometry measures FEV1 and forced vital capacity: after a maximal breath in, you blow as hard and as long as possible into a mouthpiece connected to a spirometer. The test is painless and is repeated several times to check that the attempts agree. The total volume of the lungs and the residual volume require body plethysmography, performed in a pulmonary function laboratory.

At what age does lung capacity start to decline?

Breathing capacity peaks at around 20 to 25, stays stable for a few years, then declines. According to the GLI 2012 equations, the predicted FEV1 of a 1.75 m man drops by about 31 mL per year between 30 and 70, and that of a 1.62 m woman by about 25 mL. A review of 16 cohorts indicates that this decline speeds up with each decade. The total volume of the lungs, by contrast, stays almost stable.

Why do women have lower lung capacity than men?

At the same height and age, women have smaller lungs, fewer alveoli in total and narrower airways: the male trachea has a 29% larger cross-section. The GLI equations therefore give a predicted FEV1 about 15% lower for a woman of the same height. This gap is physiological and is built into the sex-specific reference values.

Can exercise increase your lung capacity?

In healthy adults, exercise does not lastingly enlarge the lungs, but it improves endurance and reduces breathlessness for the same effort. In a European cohort of 3,912 adults, active people had an FEV1 43.6 mL higher, mainly among smokers, with no slower decline. Quitting smoking remains the most powerful lever to preserve your breathing.

Is an FEV1 of 75% of predicted abnormal?

Not necessarily, because the 80% threshold does not take age into account. According to the GLI 2012 equations, the lower limit of normal for FEV1 corresponds to about 80% of the predicted value at 30, but to 72% at 70 in a man. An FEV1 of 75% can therefore be normal at 70 and abnormal at 30. Your doctor interprets it in light of your symptoms and your history.