Summer heatwaves are becoming more common across the UK, and many people notice they're more easily out of breath when temperatures soar. Whether you're walking the dog, gardening, or simply running errands, hot weather can leave you feeling unusually breathless.
In many cases, the cause is temporary—your body is simply working harder to stay cool. Heat, humidity, dehydration, and poor air quality can all increase the strain on your heart and lungs, making breathing feel more difficult.
In recent years, the UK has experienced record-breaking summer temperatures, making it increasingly important to recognise the signs of heat-related illness and know how to stay safe.
Can Hot Weather Cause Shortness of Breath?
Yes. Feeling shortness of breath in hot weather is a normal response for many people, especially during heatwaves.
As your body tries to cool itself, your heart pumps faster, blood vessels widen, and your breathing rate naturally increases. This extra effort can leave you feeling winded, even after light activity.
If you already have asthma, COPD, heart disease, or another long-term condition, the heat may worsen existing symptoms.
Why Is It Hard to Breathe in Hot Weather?
Several factors can make breathing in hot weather feel more difficult.
Your Body Is Working Harder
As temperatures rise, your body has to work harder to regulate its temperature. To cool itself, it:
- Increases your heart rate
- Widens blood vessels to release heat
- Produces sweat
These natural cooling processes place extra demands on your heart and lungs, which can leave you feeling more out of breath than usual—even during everyday activities, particularly outdoors.
This doesn't mean there's less oxygen in the air. Instead, your body simply needs to work harder to regulate its temperature.
Humidity Makes Breathing Feel More Difficult
Many people ask, "Why is it hard to breathe in the heat?" Humidity is often part of the answer.
High humidity can make the air feel heavier and reduce your body's ability to cool itself efficiently. As a result, breathing may feel more difficult, especially during physical activity. For people with asthma, COPD, or other lung conditions, humid air can irritate the airways and trigger symptoms such as shortness of breath, wheezing, or chest tightness.
Your body cools itself by producing sweat, but high humidity slows evaporation, making it harder to release heat and leaving you feeling hot, sticky, and uncomfortable.
Poor Air Quality Can Worsen Symptoms
During heatwaves, higher levels of ozone, pollen, and air pollution can irritate the lungs and trigger:
- Asthma symptoms
- COPD flare-ups
- Wheezing
- Coughing
- Chest tightness
- Breathlessness
If you have a lung condition, it's worth checking local air quality forecasts during periods of very hot weather. Consider limiting outdoor activities when air pollution or pollen levels are high, particularly if you have asthma or another respiratory condition.
Dehydration Adds Extra Strain
Hot weather increases fluid loss through sweating.
Even mild dehydration can:
- Reduce blood volume
- Make your heart work harder
- Increase tiredness
- Leave you feeling light-headed
- Make breathing feel more difficult during activity
Drinking water regularly throughout the day helps your body regulate its temperature more effectively.
Who Is Most at Risk?
Anyone can experience breathing difficulties in hot weather, but the risk is higher for:
- Older adults
- Babies and young children
- Pregnant women
- People with asthma, COPD, heart disease, diabetes, kidney disease, or other long-term health conditions
- Those taking medications that increase sensitivity to heat
- People who are unwell or dehydrated.
- Individuals who spend long periods outdoors or perform physically demanding work.
- People exercising in hot conditions
Could It Be Heat Exhaustion?
Breathlessness can sometimes be an early sign of heat exhaustion, particularly if it occurs alongside other symptoms.
Common symptoms of heat exhaustion include:
- Tiredness or weakness
- Dizziness
- Headache
- Nausea or vomiting
- Heavy sweating with pale, cool, clammy skin (this change may be less noticeable on darker skin tones)
- Muscle cramps in the arms, legs, or abdomen
- A raised body temperature
- Intense thirst
- Irritability
Heat exhaustion can affect both adults and children. If someone develops these symptoms, move them to a cool place, help them cool down, and encourage them to drink fluids. Prompt treatment can help prevent heat exhaustion from progressing to heatstroke.
Heat Exhaustion vs Heatstroke
|
Heat Exhaustion |
Heatstroke |
|
Heavy sweating |
Hot skin (the skin may be dry, although sweating can still occur in some cases) |
|
Dizziness and weakness |
Confusion or loss of consciousness |
|
High temperature |
A very high body temperature usually above 40°C |
|
Improves with cooling and fluids |
Medical emergency requiring immediate treatment |
Call 999 or go to A&E immediately if someone develops confusion, loses consciousness, has a very high body temperature, or is having severe difficulty breathing.
Tips to Stay Safe During Hot Weather
According to the NHS, taking a few simple precautions can help reduce the risk of heat-related illness during periods of hot weather:
- Stay out of the heat where possible. If you need to go outside, try to remain in the shade, especially between 11 am and 3 pm. Wear lightweight clothing, a wide-brimmed hat, and sunscreen, and avoid strenuous activities during the hottest part of the day.
- Keep your body cool and stay hydrated. Drink plenty of water throughout the day, enjoy cool meals and drinks, and avoid excessive alcohol, caffeine, or very hot beverages. Taking a cool shower or applying cool water to your skin can also help lower your body temperature.
- Keep your home as cool as possible. Close curtains, blinds, and windows during the day to block out heat, then open windows in the evening when the outside temperature drops. Electric fans may help if indoor temperatures are below 35°C.
- Check on vulnerable people. Monitor indoor temperatures where older adults or other high-risk individuals live and sleep, and regularly check in on family members, neighbours, or friends who may be more vulnerable to the effects of extreme heat.
These recommendations are based on NHS guidance for staying safe during periods of hot weather.
Can Portable Supplemental Oxygen Be Useful During Hot Weather?
If you're spending time outdoors during summer—whether walking, hiking, travelling, or attending sporting events—you may be looking for ways to feel more refreshed.
SunVitD3’s Boost Oxygen Canisters contain 99.5% pure supplemental oxygen in a portable, easy-to-use canister. It provides short bursts of supplemental oxygen without the need for a prescription, making it a convenient option for people who want portable supplemental oxygen during outdoor activities, travel, or exercise.
If you're spending more time outdoors this summer, Boost Oxygen can be a convenient addition to your travel or activity kit. However, it's important to understand that Boost Oxygen is not a medicine. It is not intended to treat asthma, COPD, heat exhaustion, heart disease, or any other medical condition, and it should never replace prescribed oxygen therapy or emergency medical care.
If you experience persistent or worsening breathlessness, always seek medical advice promptly.
When Should You See a Doctor?
Seek medical advice if you experience:
- Breathlessness that doesn't improve after resting or cooling down
- Chest pain
- Wheezing that's getting worse
- Blue lips or fingertips
- Frequent or unexplained episodes of breathlessness
- Symptoms that interfere with everyday activities
Sudden or severe breathing difficulties should always be treated as a medical emergency.
Final Thoughts
Feeling shortness of breath in hot weather is often your body's way of responding to increased heat and humidity. Staying hydrated, avoiding the hottest part of the day, and taking extra care if you have a heart or lung condition can help reduce your risk.
If you're planning to spend more time outdoors this summer, Boost Oxygen offers a portable source of supplemental oxygen that can be used during activities such as hiking, travel, sporting events, or recovery after exercise. Just remember that it is not a substitute for medical treatment, and ongoing or severe breathlessness should always be assessed by a healthcare professional.
Disclaimer: This article is for general informational purposes only and does not constitute medical advice.
