Asthma is more common among people with obesity, but that doesn’t necessarily mean one condition causes the other. In the U.S., people with obesity are much more likely to have asthma than the general population. A 2024 study found that 49.5 percent of adults with obesity also had asthma, compared to 8.7 percent of adults overall.

To understand the connection, it helps to look more closely at what causes each condition and whether certain risk factors might contribute to both.

What Causes Asthma?

Asthma is a chronic (long-term) lung disease that causes tightness in the chest, coughing, shortness of breath, and wheezing. For some people, symptoms occur only when exposed to triggers.

Several factors may increase the risk of developing asthma:

• Allergies — Allergic reactions to substances such as pet dander, pollen, dust mites, household pests, or mold can raise the risk of asthma.
• Infections — Certain respiratory infections in childhood, such as respiratory syncytial virus (RSV), may increase asthma risk later in life.
• Genetics — Asthma is more likely if other family members have asthma or allergies.
• Environment — Exposure to cigarette smoke, air pollution, or other harmful fumes — especially in childhood — can contribute to developing asthma.

For many people with asthma, triggers such as allergens, smoke, or pollution lead to symptom flare-ups. In exercise-induced asthma, physical activity can cause asthma symptoms, even if the original cause of the condition is unrelated.

Can Obesity Cause Breathing Problems?

Doctors diagnose obesity using body mass index (BMI) — a number calculated from a person’s height and weight. A BMI of 30 or higher is considered a diagnosis of obesity.

While obesity and asthma are related, obesity does not directly cause asthma. Scientists don’t fully understand the connection, but they have identified some possible links and shared risk factors.

Obesity Can Put Pressure on the Lungs

Carrying excess body fat can put pressure on the lungs and make breathing more difficult. This effect can vary depending on where the weight is distributed on your body.

Obesity may have more of an impact on breathing if most of the excess weight is carried in the chest and abdomen, rather than the hips or thighs. When fat builds up around the organs in the chest and belly, it can limit lung expansion and put pressure on the airways, making it harder to breathe.

Obesity Can Make Asthma Worse

People who have both obesity and asthma are more likely to experience severe asthma and complications than people with asthma alone. In fact, people with both conditions are four to six times more likely to be hospitalized for asthma attacks than those with asthma and lower body weight.

Higher BMI is also linked to increased risk of asthma attacks. One study found that people with a BMI over 25 had an average of 1.5 asthma attacks per year, compared to 0.4 per year for people with a BMI under 25.

Obesity Causes Inflammation, a Known Asthma Trigger

Fat tissue releases hormones that help regulate body function. Having more fat in your body can result in excess levels of these hormones, causing inflammation and metabolic issues. Chronic inflammation can reach your airways and make it harder to breathe. Inflammation is also linked to both asthma and other obesity-related diseases, including heart disease and chronic obstructive pulmonary disease (COPD).

Asthma Can Make Obesity Harder To Manage (and Vice Versa)

If you’re living with both obesity and asthma, you may already know that managing these conditions together can be challenging. Each can affect how the other is treated, which can be frustrating and make symptom control more difficult.

Obesity Can Affect How Asthma Medications Work

People with obesity may not respond as well to two of the most common medications used in asthma control inhalers: corticosteroids and long-acting beta agonists (LABAs). For some, inhaled corticosteroids are less effective due to steroid resistance, meaning these medicines might not work as well as expected.

Studies show that people with obesity often need higher doses of inhaled corticosteroids to achieve the same level of asthma control as those without.

Asthma Medications Can Contribute to Weight Gain

Many people with asthma take prednisone, a corticosteroid, during severe flare-ups. Unfortunately, weight gain is a known side effect of prednisone.

One MyObesityTeam member described their frustration: “I am on prednisone, it’s driving me nuts, I keep being hungry.”

Another member took a hopeful view: “I took steroids for my breathing, and that caused a lot of weight gain. But I never gave up. Every little thing you do to try to be healthy helps you, even if you can’t see it.”

Asthma Can Make It Harder To Stay Active

Getting regular physical activity is an important part of managing both asthma and obesity — but asthma symptoms can make it hard to stay active.

One MyObesityTeam member put it this way: “I have asthma along with my weight gain. It seems no one understands that I can’t exercise like them or go, go, go like they do.”

Said another, “I’m having a difficult time breathing today. It’s impossible to do any kind of activity, which is what I need to be doing.”

Talk with your doctor about types of movement or exercise that are safe and manageable with asthma. They may be able to recommend options that work with your current symptoms and energy levels.

Talk to Your Healthcare Provider

If you’re wondering, “Will losing weight help with asthma?” the answer is that it very well could. Research has shown a link between weight loss and improved lung function and fewer asthma symptoms. “Since I’ve lost weight, breathing has become so much easier,” said one MyObesityTeam member.

Improving asthma control may also make it easier to pursue your goals for managing obesity, which might include increasing your energy, improving mobility, reducing joint pain, or losing weight. Activities like walking, stretching, or other gentle forms of exercise can strengthen your lungs and help improve overall fitness. These changes may also lead to better asthma control and more energy for daily life.

Whatever your goals, talk with your healthcare provider about a treatment plan that’s tailored to your needs. You might also consider seeing a specialist who can help you manage both asthma and obesity in a coordinated way.

Talk With Others Who Understand

MyObesityTeam is the social network for people with obesity and their loved ones. On MyObesityTeam, members come together to ask questions, give advice, and share their stories with others who understand life with obesity.

Are you living with both obesity and asthma? What are some treatment approaches that have worked for you to help manage both? Share your comments below, or start a conversation by posting on your Activities page.