The condition of our lungs can reveal a great deal about our wider health. Luckily you can also get them into better shape.

How old do you think your lungs are? With every breath, they are exposed to a myriad of pollutants, microbes, dust and allergens. Unsurprisingly this can take a toll on these delicate organs, accelerating how they age. But they also can affect how the rest of your body ages too. 

In early May 2025, an international team of respiratory experts published one of the first ever studies to assess how human lung function varies as we age. Based on data from some 30,000 men and women collected over the course of the 20th Century, it showed that our lung function peaks in our early to mid-20s. Women's lung capacity typically tops out a few years earlier than men's – before declining thereafter.

This, according to Judith Garcia-Aymerich, a professor at the Barcelona Institute for Global Health who led the study, appears to be a biologically programmed part of ageing, she says. Factors such as smoking, air pollution and flare-ups of conditions like asthma can all exacerbate this decline.

The better your lung capacity is at this peak age, however, the more resilience you will have against chronic respiratory diseases and other lung-related health conditions later in life, says Garcia-Aymerich. But lung health is also linked to a wide range of other more surprising aspects of your health, affecting your immune system, your weight and even your brain (read on to find out why later in this piece).

So just how healthy are your lungs? And can you do anything to improve the state they are in? 

Studies like the one described above use expensive equipment to measure lung health, but there is a simple way to test your lungs at home. All you need is a large plastic bottle, a bucket or bathtub and a length of rubber tubing. And then do the following (you might want to do it in a sink or outside as it can get a bit messy):

1. First, measure out 200ml (7fl oz) of water into a measuring jug, transfer to the plastic bottle and use a pen to mark the water level.

2. Add another 200ml of water, mark the new water level and repeat the process until the bottle is full.

3. Fill the bucket or bathtub with water and dip the now full bottle into it, turning the bottle upside down under the water.

4. Keeping the bottle in this position, place the rubber tubing inside the bottle neck. It doesn't have to fit tightly.

5. Take a deep breath and blow into the tube.

6. Count how many lines of water you can blow out of the bottle.

7. Multiply the number of lines by 200ml. (eg three lines is 600ml). This number is your vital lung capacity, also referred to as forced vital capacity or FVC.

 

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"The test looks at the volume of air you can breathe out, which has been termed vital [lung] capacity," says John Dickinson, who heads the exercise respiratory clinic at the University of Kent. "This term was first used by English surgeon John Hutchinson in the 1840s. He started to notice that those who could only breath small volumes of air had less time to live."

According to the American Lung Association, FVC can decrease by about 0.2 litres per decade, even in healthy people who have never smoked, due to the effects of ageing. Research suggests that a normal healthy FVC is between three and five litres.

Dickinson says that you should not be overly concerned if you get a lower reading from this home health test. "A lot of people will struggle to completely empty their lungs so may get false low readings," he says. 

But there are also ways of improving your lung health and combating any decline in their performance. And if you want to age gracefully, this may be a vital step.

How your lungs affect your wider health

Research shows that as we age, we experience a loss of elasticity in our lung tissue, a weakening of respiratory muscles like the diaphragm and changes in the rib cage that limit its ability to expand and contract. "If the loss of lung function is excessive, people can feel symptoms like shortness of breath," says Garcia-Aymerich. "It can lead to a condition called chronic obstructive pulmonary disease (COPD) characterised by low lung function levels."

But worsening lung health does not only make you more susceptible to lung disease. It is also linked to a surprising range of other illnesses, from elevated blood pressure to autoimmunity, metabolic diseases, frailty and even cognitive decline.

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Dawn Bowdish, a professor at McMaster University in Canada, who specialises in ageing and immunity, says one reason for this is that the lungs are inextricably linked to the heart and the circulation, as well as having a major connection with the health of our wider immune system via what she calls the "lung-immune axis".

"The lung has millions and millions of immune cells that have important functions like clearing particulate air pollution, fighting infections, and repairing the damage that comes from the constant stretching of breathing in and out," she says.

According to Bowdish, if the lung's immune cells are unable to clear all the particles that gather in the lungs, they trigger increasing levels of inflammation, which can lead to lung scarring, known as pulmonary fibrosis. This makes the lungs stiffer and less able to function. Inflammation in our lungs can also lead to changes in the way our body reacts to respiratory infections as the immune response can cause further harm.

Lower lung function has also been found to precede other age-related health issues, including heart disease, osteoporosis, type 2 diabetes and reductions in memory – although the exact nature of this relationship is still to be understood. Bowdish believes inflammation from our lungs may spread throughout the body.

The benefits of healthy lungs

The relationship between our lungs and wider health is also two-way. Bowdish says that if we keep our lungs relatively healthy, we are more likely to remain disease free for longer in later life.

"Even though lung capacity declines with age, this is not a cause for concern for those who look after their lung health," adds Dickinson. "Healthy lungs have more than enough capacity to supply the body with oxygen and remove carbon dioxide throughout the lifespan. However, if the rate of decline increases, our health and quality of life may be impacted." 

If you are concerned about your lungs, Dickinson recommends going to your doctor for a proper lung function test, which involves breathing into a device called a spirometer which measures the volume and speed of your breath.

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A spirometer will calculate your FVC to medical-grade accuracy along with your forced expiratory volume (FEV1) – the amount of air you can exhale in one second after taking a deep breath. It will also give you the ratio of the FEV1 to FVC, which can indicate if you have anything obstructing your airflow. Combined, these metrics provide an overall picture of your lung health.

"Ideally, I would recommend people have their lung function [clinically] assessed every 10 years if they are not experiencing any symptoms, but they should have it tested immediately if they are experiencing abnormal breathlessness symptoms," says Dickinson.

Improving your lung function

Once you know the state of your lungs, evidence shows there are some preventative steps which you can take to improve your lung capacity and help mitigate age-related decline. 

Regular exercising, for example, can reduce airway inflammation and improve the strength and endurance of breathing muscles. Lowering salt in the diet could also be beneficial as research suggests that excess dietary salt can worsen lung inflammation and fibrosis. A diet richer in fish oils, antioxidants and vitamins C and E, meanwhile, is also thought to help protect the walls of the lungs from damage.

Bowdish recommends quitting both smoking and vaping to avoid ingesting any potentially inflammatory chemicals. According to Daniel Craighead, an assistant professor at the University of Minnesota, another way of maintaining good lung function is to keep to a healthy weight and avoid acquiring excess body fat. "Abdominal fat can impede the ability of the lungs to fully fill with air," says Craighead.

But there's another means by which we may be able to actually improve lung function. Since the mid 1990s, inspiratory muscle training (IMT) or breathing in through a device which provides a resistance, has become known as a way of boosting respiratory muscle strength in groups ranging from athletes and singers to people with existing breathing difficulties such as asthma and COPD. Research has shown that IMT can improve exercise capacity and lower blood pressure.

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The gold standard method for IMT is a medical device known as Powerbreathe which is recognised as an approved medical product by the UK's National Health Service (NHS) and other health services. It has been highlighted by the World Health Organisation (WHO) as a tool to support Covid recovery and is also utilised by hospitals around the world for prehabilitation – improving people's lung function ahead of surgery to increase their chances of making a good recovery – as well as a treatment for pulmonary fibrosis, and to support those who have been on ventilators in intensive care. 

According to Craighead, studies have typically shown that two 30-breath IMT sessions a day is sufficient to improve respiratory muscle strength.

Sabrina Brar, medical officer at Powerbreathe International, compares carrying out IMT through the device to weightlifting for your arm and leg muscles. "Strengthening the muscles responsible for breathing in, much like strengthening any other muscle in the body, will increase respiratory muscle endurance and strength and reduce age-related lung function decline," says Brar. "The idea is to engage the diaphragm and intercostal muscles and then periodically increase the resistance over time as lung strength improves." 

Another option is to simply take up singing or playing a wind instrument. Researchers at the Louis Armstrong Centre in New York City have pioneered this approach through attempting to improve the lung function of people with asthma by teaching them to play various wind instruments. Other scientists have even designed an electronic version of a type of flute called the ocarina to assist in improving lung function.

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As an assistant professor at the University of Southern Denmark and a trained classical singer herself, Mette Kaasgaard has been involved in a number of trials looking at how singing can potentially help people with COPD.

While Kaasgaard says that there is no evidence to suggest that singing can actually reverse existing lung damage, she believes that it might still benefit lung health by improving our ability to utilise our respiratory muscles.

"A central aspect of singing is the ability to sing long phrases, which requires control and flexibility of the diaphragm, the muscles in between the ribs and the abdominal muscles," she says.

But whichever lung workout you choose, it can help these vital organs cope with all the world throws at them – one breath at a time.