Can obesity cause asthma?

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Can obesity cause asthma? Discover the links between obesity and asthma, plus safe options for weight management.

Asthma and obesity are two of the most common long-term conditions in the UK. Up to 5.4 million people in this country receive asthma treatment, and more than a quarter of adults live with obesity.

So, are the two related? Can obesity cause asthma – or is asthma related to obesity in a different way?

While it is true that excess weight increases the risk of developing asthma and can make symptoms harder to control, it's rarely the only cause. Genetics, environment and immune factors also play significant roles.

Let's investigate.

What is asthma?

Asthma is a long-term condition where the airways in your lungs become extra-sensitive.

When they're irritated, the muscles around them tighten and the lining swells. This can make you wheeze, feel short of breath, cough or notice a tight feeling in your chest.

Symptoms can come and go and are often set off by things like:

Pollen or dust
Colds and flu
Cold air
Exercise

How is it treated?

Many people use two types of inhalers to help treat their asthma:

Preventer inhaler: this is used daily to calm the airways and reduce swelling, helping to stop symptoms from starting.
Reliever inhaler: this is used to relax the airway muscles when you have symptoms, so you can breathe more easily.

Some people may also be offered add-on treatments if symptoms aren't well controlled.

Does obesity cause asthma?

Living with obesity doesn't cause asthma for everyone. However, it does raise your chances of developing it.

Research in adults shows a strong, dose-dependent link – the higher the BMI, the higher the risk of new-onset asthma. BMI is a measure of fat in the body.

Why might weight affect asthma?

Pressure on the lungs: extra weight can reduce lung volumes and lead to small airways closing more easily, so breathing feels harder.
Body-wide inflammation: fat tissue releases chemicals that can increase airway inflammation and sensitivity.

Metabolic and hormone changes: insulin resistance and other hormone shifts linked to obesity can make asthma harder to control.

What this means for you

Obesity doesn't explain every case of asthma. However, as we've seen, it can increase the likelihood of developing it. It's also linked to more symptoms and a poorer response to standard treatment for some adults.

Moreover, obesity makes it more likely to develop asthma later in life. There's a recognised obesity-related asthma pattern that often starts in adulthood and can be tougher to manage than childhood asthma.

The impact of weight loss on asthma

Are you living with asthma and obesity? We have some good news: losing weight can improve asthma symptoms.

Studies show that lifestyle changes leading to weight loss improve day-to-day control of asthma symptoms. Bariatric surgery has also been linked with better lung function and fewer symptoms in many patients.

If asthma affects you, a plan that supports gradual, sustainable weight loss alongside your inhalers may help you breathe more easily.

Options for managing weight when you have asthma

Healthy lifestyle changes

Eating a balanced, lower-calorie diet that focuses on whole foods, protein and fibre can help you feel fuller and keep blood sugar steady. And gradually increasing activity (with a mix of resistance and aerobic exercise) can help improve fitness and insulin sensitivity.

All this can improve asthma symptoms – indirectly – by promoting weight loss and reducing the complications that make asthma worse. Your doctor may be able to offer support to help you adjust your lifestyle and reap the benefits of weight loss.

However, before you pursue any lifestyle changes, it's important to talk to your doctor first. That's so they can review your asthma plan and make sure you can exercise safely.

GLP-1 injections for obesity

These medicines are not asthma treatments – instead, they target weight and metabolic drivers. However, these can indirectly improve asthma by reducing strain on the lungs and lowering inflammation.

Wegovy (semaglutide)

Wegovy is a once-weekly injection that helps you feel full and curbs hunger cravings. It works by mimicking a natural hormone (GLP-1) that slows digestion and controls blood sugar levels.

The NHS began offering Wegovy in September 2023. It's currently only available to adults who meet strict eligibility criteria.

In a large clinical trial, Wegovy users lost an average of 14.9% of their starting weight when taking the drug alongside lifestyle changes.

Mounjaro (tirzepatide)

Mounjaro also helps curb hunger cravings and keep blood sugars balanced. It mimics the same hormone as Wegovy (GLP-1), plus another called 'GIP'.

That might be one reason Mounjaro tends to be more effective than Wegovy. In a large clinical trial, Mounjaro users saw a 20.9% average weight loss with lifestyle changes. That's 6% more than Wegovy.

In 2025, NHS England began a phased rollout of Mounjaro – mainly through specialist services with limited primary-care access.

Your next steps

Do you want to lose weight to improve asthma symptoms? It's not always easy – but with the right plan, you might see results more quickly than you think.

It's good to focus on what you can change. Even modest weight loss can improve lung function, reduce day-to-day symptoms and help your medicines work better.

To help with your symptoms, you can pair asthma care with evidence-based weight management. That might include a tailored activity plan, nutrition support and, for some people, weight-loss medicines.

It's best to talk to your healthcare provider first – especially if your asthma is triggered by exercise. They can help you develop an approach that fits your health and goals.

SemaPen: safe, professional support from a trusted private clinic

At SemaPen, we provide a safe and regulated way to begin weight loss treatment with Mounjaro or Wegovy.

Your journey starts with an online consultation reviewed by one of our obesity experts. If an injectable weight loss medication is appropriate, we issue a private prescription and build a weight loss programme around you. This includes progress reviews, nutrition guidance and a smart scale you can use at home to track changes with your care team in real time.

Safety comes first. We screen for contraindications, review other medicines and give clear guidance on side effects and what to do if they occur. You'll also have access to ongoing clinical support – and our pricing is transparent, with a money-back guarantee for your peace of mind.

Want to get started with SemaPen? When you take our online consultation, we'll let you know straight away if you're eligible for treatment.

Sources and small print

1. NICE (2025) Asthma: How common is it? Retrieved from https://cks.nice.org.uk/topics/asthma/background-information/prevalence/

2. Office for Health Improvement & Disparities (2024) Obesity Profile: short statistical commentary May 2024. GOV.UK. Retrieved from https://www.gov.uk/government/statistics/update-to-the-obesity-profile-on-fingertips/obesity-profile-short-statistical-commentary-may-2024

3. Beuther, D.A. & Sutherland, E.R. (2007) "Overweight, Obesity, and Incident Asthma: A Meta-analysis of Prospective Epidemiologic Studies" American Journal of Respiratory and Critical Care Medicine, 175(7) https://doi.org/10.1164/rccm.200611-1717OC

4. Parasuaraman, G. et al. (2023) "The association between body mass index, abdominal fatness, and weight change and the risk of adult asthma: a systematic review and meta-analysis of cohort studies" Scientific Reports, 13(7745) https://doi.org/10.1038/s41598-023-31373-6

5. Peters, U. et al. (2018) "Obesity and Asthma" The Journal of Allergy and Clinical Immunology, 141(4) https://doi.org/10.1016/j.jaci.2018.02.004

6. Ma, J. et al. (2015) "Behavioral weight loss and physical activity intervention in obese adults with asthma. A randomized trial" Annals of the American Thoracic Society, 12(1) https://doi.org/10.1513/annalsats.201406-271oc

7. Chaaban, T.A. (2019) "Bariatric surgery: a potential cure for asthma?" European Respiratory Review, 28(152) https://doi.org/10.1183/16000617.0003-2019

8. Wilding, J.P.H. et al. (2021) "Once-weekly semaglutide in adults with overweight or obesity" The New England Journal of Medicine, 384(11) https://doi.org/10.1056/NEJMoa2032183

9. Jastreboff, A.M. et al. (2022) "Tirzepatide Once Weekly for the Treatment of Obesity" The New England Journal of Medicine, 387(3) https://doi.org/10.1056/NEJMoa2206038

* Terms and conditions apply.

This article was reviewed and approved by Alice Fletcher, Lead Bariatric Dietitian, on 3 September 2025.

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