A faster heartbeat is a normal part of an asthma flare-up, the body’s response to struggling for air. The racing heart usually comes more from the attack itself than from the rescue inhaler people often blame. Over the long run, how well your asthma is controlled seems to matter for the heart as much as the attacks do.1PubMed Central. Associations of Asthma and Asthma Control With Atrial Fibrillation Risk: Results From the Nord-Trøndelag Health Study (HUNT)
Why Your Heart Speeds Up During an Asthma Attack
When your airways narrow, less oxygen gets into your blood. The heart responds by beating faster, moving the oxygen that is there around the body more quickly. Low oxygen also makes the heart’s reaction to blocked breathing stronger than the blockage would cause alone.2American Review of Respiratory Disease (PubMed Central / ATS Journals). Cardiovascular response to acute airway obstruction and hypoxia
Effort adds to the load. Your breathing muscles work hard and use extra oxygen themselves, which pulls the heart rate higher still. In a long attack, exhaustion can make things worse quickly.
The pressure inside your chest matters too. In a bad attack, breathing in takes a strong suck of pressure inside the chest, and breathing out pushes hard against the blockage.3PubMed. Mechanism of paradoxic pulse in bronchial asthma On each breath in, the right side of the heart swells and crowds the left side for space. The left side then fills with about a third less blood on each inward breath.4PubMed. Mechanism of paradoxic pulse in bronchial asthma Blood pressure and pulse strength rise and fall with each breath, something doctors check for in severe asthma.5PubMed. Mechanism of paradoxic pulse in bronchial asthma
What you feel is often pounding or fluttering in the chest alongside tightness and wheeze. Stress and fear release adrenaline, which pushes the rate up further.
After a rescue inhaler, the pulse should drift down over the following minutes to an hour, so its direction is a useful clue to whether treatment is working. A rate that stays high while breathing isn’t improving suggests the airways are still blocked and the attack isn’t under control. If the pulse is falling but you still feel shaky, that is more likely the medicine than the attack continuing.
Children run differently. Their normal resting heart rates are faster than adults’, and the younger the child, the faster the normal rate, so a pulse that would alarm you in an adult may be ordinary in a small child. The better comparison is your child’s usual rate when well and calm against the rate during the flare-up.
Does Your Rescue Inhaler Make Your Heart Race
Albuterol (salbutamol in some countries) is the usual blue rescue inhaler. It relaxes the airways but can also stimulate the heart. Still, in hospital patients given nebulized albuterol, heart rate rose by only about 4 beats per minute on average.6PubMed. Changes in heart rate associated with nebulized racemic albuterol and levalbuterol in intensive care patients In patients whose hearts were already racing, it added under 2 beats per minute.7PubMed. Changes in heart rate associated with nebulized racemic albuterol and levalbuterol in intensive care patients When an attack has already sped the heart up, the medicine adds little, and opening the airways may help the heart slow down. Levalbuterol, sometimes offered as gentler on the heart, raised heart rate by a similar amount.8PubMed. Changes in heart rate associated with nebulized racemic albuterol and levalbuterol in intensive care patients
Daily preventer inhalers look safe for the heart as well. In children using inhaled steroid preventers, heart rhythm patterns matched those of children without asthma, day and night.9Asthma Allergy Immunology. Is There An Effect of Inhaled Steroid Treatment on Heart Rate?
Shakiness and a quick pulse within minutes of a puff are common side effects of your rescue inhaler, and they usually fade within an hour or so. A racing heart with worsening breathing points to the attack, not the medicine.
The same puff can feel different from one day to the next. Puffs taken in quick succession during an attack give a bigger effect than a single puff, which is why the jittery feeling is stronger after a long episode.
Needing the inhaler much more often than usual signals poorly controlled asthma. If you are reaching for it several times a week, tell your doctor.
A spacer, a tube that attaches to the inhaler, helps more of the medicine reach your lungs instead of your mouth and throat. If your usual dose isn’t working, follow your action plan and seek help rather than taking extra puffs on your own.
At appointments, mention palpitations and any heart conditions you have. Ask whether a preventer could cut your rescue inhaler use. Bring a list of all your medicines, as some heart drugs can tighten airways.
When a Fast Heart Rate Means Get Help Now
In severe childhood asthma, a fast heartbeat may come with sweating and chest pain.10Mayo Clinic. Childhood asthma: Symptoms and causes Seek emergency care if a child shows any of these:
- Has to stop mid-sentence to breathe11Mayo Clinic. Childhood asthma: Symptoms and causes
- Is using stomach muscles to breathe12Mayo Clinic. Childhood asthma: Symptoms and causes
- Has nostrils flaring on each breath in13Mayo Clinic. Childhood asthma: Symptoms and causes
- Has the stomach sucking in under the ribs with each breath14Mayo Clinic. Childhood asthma: Symptoms and causes
The same signs, plus a rescue inhaler that isn’t helping, mean an adult needs urgent care too. Bluish lips or confusion are signs of very low oxygen and need an ambulance.
A fast pulse alone doesn’t tell you how serious an attack is, because fear, exertion and the inhaler can all raise it. The breathing signs are the more reliable guide, so don’t wait for the pulse to settle before acting.
While waiting for help, follow your written asthma action plan and use the rescue inhaler as it directs. Sit upright and stay as calm as you can. If symptoms keep worsening, call emergency services.
Night-Time Heart Rate and Early Warning of Attacks
In people with asthma, average overnight heart rate measured by smartwatch ran higher than in people without asthma. It rose about a week before an asthma attack and fell once rescue medicine was used.15PubMed Central. Digital markers of asthma exacerbations: a systematic review So a creeping rise in your resting night heart rate could be a hint worth noting.
Tracking has limits. In children monitored at home overnight, a model using body signals flagged symptoms a day ahead only about a third of the time.16PubMed Central. Passive Nocturnal Physiologic Monitoring Enables Early Detection of Exacerbations in Children with Asthma. A Proof-of-Concept Study Trackers can add clues but cannot replace symptoms, peak flow, and your action plan.
Something else is going on in the early hours. The nervous system of people with asthma shifts toward its calming branch, the reverse of people without asthma.17Taylor & Francis Online / Chronobiology International. Circadian rhythmicity of heart rate variability and its impact on cardiac autonomic modulation in asthma That shift is one reason asthma often worsens at night and early morning. It is one contributor among several: lying flat, cooler bedroom air and dust mites in bedding can also add to nighttime symptoms. A restless night with a faster heart is therefore not automatically a sign of heart trouble. The cause may be the airways.
Most watches estimate pulse using light sensors on the wrist, and a loose strap or movement can throw the readings off. A watch reports a pulse, not breathing or oxygen in the airways, so it cannot tell you directly that an attack is coming.
To use one sensibly, look at trends over a week, not single readings. Note resting night heart rate along with any cough or waking. Colds, alcohol and poor sleep also raise night heart rate. Share the pattern with your doctor rather than changing medicine yourself.
Asthma and Irregular Heartbeat Risk
Atrial fibrillation is an irregular, often fast heartbeat that can raise stroke risk. People with diagnosed asthma had about a 38% higher chance of developing it.18PubMed Central. Associations of Asthma and Asthma Control With Atrial Fibrillation Risk: Results From the Nord-Trøndelag Health Study (HUNT) The risk climbed step by step with worse control, reaching about 74% higher with uncontrolled asthma.19PubMed Central. Associations of Asthma and Asthma Control With Atrial Fibrillation Risk: Results From the Nord-Trøndelag Health Study (HUNT) Asthma needing daily controller medicine carried about 1.5 times the risk, while occasional asthma showed no rise.20PubMed. Persistent Asthma Is Associated With Increased Risk for Incident Atrial Fibrillation in the MESA
Researchers have not pinned down one cause, and the link is an association, not proof that asthma directly causes the rhythm problem. Repeated inflammation, low-oxygen episodes and the strain of forced breathing are among the ideas proposed. Some asthma and heart medicines can also affect the heart’s rhythm or the airways, which is one reason your doctor needs the full list of what you take.
Even among people with persistent asthma, new cases were roughly 2 per 100 people per year.21PubMed. Persistent Asthma Is Associated With Increased Risk for Incident Atrial Fibrillation in the MESA A 38% higher chance is a relative figure that compares your risk with someone else’s, and because the starting chance is low for most younger adults, a modest rise still leaves the actual chance small. Age, blood pressure and weight matter far more for most people.
The two kinds of fast heartbeat feel different. A fast regular beat feels steady and quick. An irregular heartbeat feels chaotic, fluttering or skipping, and it may come with dizziness or breathlessness at rest. An irregular pulse that persists should be checked by a doctor.
Long-Term Effects on the Heart
Adults with asthma developed heart disease about 28% more often, even after accounting for usual heart risks.22PubMed Central. The Relationship Between Asthma and Cardiovascular Disease That is an association and doesn’t prove asthma itself causes heart disease.
Repeated low oxygen can tighten small lung blood vessels, raising the pressure the right side of the heart must pump against.23PubMed Central. Functional assessment of the right ventricle in patients with bronchial asthma of various severity In severe cases this extra load can seriously strain heart and lungs.24PubMed Central. Functional assessment of the right ventricle in patients with bronchial asthma of various severity Over a long time that extra work can wear down the right side of the heart, but this is mainly a concern in severe, long-standing disease. Most people with well-managed asthma are not in this situation.
Heart rate variability, the small beat-to-beat changes in rhythm, tends to be lower with poorly controlled asthma.25PubMed Central. Autonomic modulations in patients with bronchial asthma based on short-term heart rate variability But in one group where control was compared fairly, rhythm patterns matched healthy people.26PubMed Central. Patterns of heart rate variability and cardiac autonomic modulations in controlled and uncontrolled asthmatic patients The evidence here is mixed.
To protect your heart, keep asthma controlled with preventers as prescribed. Don’t smoke, and avoid smoke exposure. Get blood pressure and cholesterol checked regularly. Untreated sleep apnea alongside asthma adds strain, so report heavy snoring.
Regular activity is safe for most people with controlled asthma. Use a pre-exercise inhaler if one is prescribed, and warm up gradually to limit exercise-triggered symptoms.