On a spring afternoon, a child sprints across a school field, cheeks flushed, arms pumping—then suddenly slows, shoulders hunched, breathing sharp and fast. The run ends not with laughter, but with wheezing. Many parents recognize this scene. Many adults do too—especially when pollen counts climb, temperatures swing, and air quality slips.

Asthma is a fact of life for millions. More than 28 million Americans have asthma, including nearly one in 15 children, according to national estimates.

Yet there is good news. Doctors now understand asthma more deeply than as “tight airways,” and modern treatment increasingly targets the underlying driver—inflammation—to provide longer, steadier relief.

That shift was a major theme in a recent “Vital Signs” conversation with Dr. Edward Eden, a pulmonologist, professor of medicine, and clinical director of the James P. Mara Center for Lung Disease at Mount Sinai in New York.

Asthma Isn’t Just Airway Tightening

Asthma is often described as bronchial tubes that constrict—muscles tightening around the airways. That is real. However, it’s only part of the story.

Asthma is also “an inflammatory condition,” Eden said, meaning the lining of the airways can swell and produce extra mucus—fueling the familiar triad of coughing, wheezing, and shortness of breath.

This distinction matters because a medication that only relaxes airway muscles may provide quick relief, but if inflammation persists, symptoms often rebound.

Why Spring and Fall Can Feel Like Asthma ‘Seasons’

If you have asthma, you may notice predictable trouble spots at certain times of year. Spring commonly brings an uptick in symptoms, and fall can be another peak, Eden said.

Two major culprits stand out. First, trees and plants release allergenic pollen in spring. Second, shifts from cool to warm air can irritate sensitive airways.

Air quality also plays a role. Eden noted ozone as a potent airway irritant—sometimes at surprisingly low concentrations—especially in summer months.

Research also continues to link early-life exposure to air pollutants, including PM2.5 and nitrogen dioxide, with a higher risk of childhood asthma.

Exercise-Induced Asthma

Children face unique challenges that make them particularly susceptible to asthma symptoms during physical activity.

Many children frequently experience wheezing or shortness of breath during physical activity, a condition commonly referred to as exercise-induced asthma, Eden said. Rapid breathing during exercise exposes the airways to sudden changes in temperature and humidity, which can trigger airway constriction.

Because children’s lungs are still developing, their bronchial tubes are smaller and more sensitive than those of adults. Even mild inflammation can significantly restrict airflow.

“If the airway starts small, as it does in children, it takes much less constriction to trigger an asthma attack,” Eden said. He compared the effect to a narrow pipe, where a small blockage can dramatically reduce flow.

Young immune systems also respond more strongly to irritants and allergens. “Children are more vulnerable because their immune systems are more acute and sensitive,” Eden said. “As people age, the immune system becomes less responsive.”

Many children experience fewer symptoms as they grow and their airways enlarge. However, Eden noted that asthma can return later in life if underlying allergies persist.

Why Swimming Helps 

Swimming is often recommended for people with asthma because it combines physical activity with favorable breathing conditions.

Warm, humid air, especially in indoor pools, also helps reduce airway irritation compared with cold or dry outdoor air.

“The humidity and temperature help reduce exercise-related asthma symptoms,” Eden said.

For other forms of exercise, Eden recommended several precautions:

• Use prescribed inhalers before activity, if advised by a physician


• Avoid outdoor exercise during high-pollen or high-pollution periods


• Exercise indoors during allergy season when possible

What’s Behind the Rise?

Asthma rates haven’t risen for one reason alone. Part of the apparent increase is better recognition and diagnosis. However, factors of modern life can also increase susceptibility:

1. Pollution and Traffic Exposure: Children growing up in high-traffic or polluted areas may face higher asthma risk, Eden noted. Extensive studies and reviews support the connection between traffic-related air pollution and asthma development.

2. Obesity and Inactivity: Eden calls the link between asthma and obesity “very interesting,” but he also notes uncertainty about the exact mechanism. Scientific reviews suggest obesity can worsen asthma control and increase exacerbations, especially in children and adolescents, though pathways vary and are still being mapped.

3. Low Vitamin D: Vitamin D deficiency has been proposed as a contributing factor, which Eden describes as a hypothesis with more association than proven cause.

The research on vitamin D and asthma is nuanced. A 2023 Cochrane review found no clear reduction in exacerbations requiring systemic steroids overall with vitamin D supplementation. Some newer studies suggest benefit in specific pediatric groups, but findings are not uniform across the broader asthma population.

4. The ‘Too Clean’ Paradox: Here’s where asthma science becomes almost counterintuitive. Eden pointed out an observation seen in research for decades—that children with more exposure to animals and “playing in the dirt” often have less asthma than children raised in very clean environments.

Large cohort studies of children raised on farms have found that early exposure to animals, soil, and farm dust is associated with a lower incidence of asthma and allergic diseases. Researchers believe exposure to a wide range of microbes helps train the immune system to tolerate harmless substances.

The hygiene hypothesis proposes that reduced exposure to microbes in highly sanitized environments can impair immune development, increasing the risk of asthma and other allergic conditions.

The Big Shift in Treatment

For years, asthma care often leaned heavily on rescue inhalers that quickly open airways. Bronchodilators can be lifesaving in the moment—but they don’t address the chronic inflammatory process.

Doctors now recognize different types of asthma, driven by distinct immune pathways, and that newer medications are increasingly designed to target specific inflammatory processes more precisely, Eden said.

The Global Initiative for Asthma (GINA) states that short-acting beta-agonist-only bronchodilator treatment is no longer recommended for asthma because it leaves underlying inflammation untreated and is associated with a higher risk of exacerbations.

Combination Inhalers

Eden described today’s mainstream approach as pairing a bronchodilator with an anti-inflammatory medication—often an inhaled corticosteroid.

It’s a practical shift for some patients, he noted. Clinicians increasingly use a combination inhaler for symptom relief rather than relying on a bronchodilator alone—because bronchodilators wear off while inflammation persists.

The GINA updates highlight strategies such as ICS-formoterol, a combination inhaler that uses an inhaled corticosteroid to reduce airway inflammation and formoterol, a long-acting bronchodilator to open airways as relievers to reduce asthma exacerbations.

Access–the Hidden Barrier

Access to effective medications can be complicated, even when they are available.

Insurance coverage may favor specific brands, and if the prescribed inhaler isn’t covered, patients can face delays, switch medications, or rely solely on short-acting rescue inhalers, Eden noted. Over-reliance on short-acting bronchodilators may lead to poor control and, ultimately, emergency visits, he said.

A practical patient takeaway is that if a medication that worked for years suddenly becomes unaffordable after an insurance change, ask your clinician about covered equivalents rather than going without.

What You Can Control at Home

Eden offered common-sense strategies for reducing indoor asthma triggers, especially for people sensitive to dust and dust mites—tiny organisms that can live in bedding and soft furnishings:

• Reduce exposure to high-pile carpets that trap dust


• Clean bedding regularly


• Consider mattress covers in certain situations, such as for those with confirmed dust-mite allergies, frequent nighttime symptoms, or poorly controlled asthma

An important nuance is that while allergen reduction is widely recommended for people with allergies, large systematic reviews have found that dust mite control measures often don’t translate into clear symptom improvement across the general asthma population—a reminder that asthma is highly individualized and that a single home “fix” may not work for everyone.

Regarding smoking and vaping, we still don’t fully know the long-term implications for asthma rates, but avoiding smoke exposure remains the safer choice, Eden said.

When to Seek Help

Asthma can be frightening, but for most people, asthma is reversible and controllable with appropriate medications and follow-up care, Eden said.

If someone is having an acute asthma episode, he recommends contacting a clinician for guidance when possible, and in severe cases, emergency treatment may include nebulized bronchodilators and systemic steroids.

Improving long-term control to prevent repeat emergency visits is critical, he said.

Asthma is common—and for many families, it can feel like an unpredictable thief of sleep, energy, and confidence. However, the scientific perspective has shifted. Asthma is increasingly treated as a disease of inflammation and immune pathways, not just airway tightening.

For patients, the goal is no longer simply to stop symptoms in the moment, but to calm inflammation so flare-ups happen less often. With informed care, thoughtful lifestyle choices, and modern treatment strategies, most people with asthma can breathe easier—and live fully.