Asthma and Hydration

What is Asthma? 

Asthma is a disorder characterized by the narrowing of airways as a result of chronic inflammation of the lungs due to a hypersensitive airway. 

The airway reacts to a variety of stimuli or triggers that can lead to breathing difficulties. The most common symptom of asthma is wheezing, which can be identified as a whistling or squealing sound while breathing. Asthma causes frequent episodes of wheezing, tightness of the chest, breathing difficulties, and coughing at night or early in the morning. 

Links between Asthma and Dehydration

There is no treatment to cure asthma, but its symptoms can be managed by reducing the triggers that stimulate asthmatic attacks. 1-5 

The asthma patient may experience severe dehydration, which is directly proportional to the frequency and severity of the asthmatic attack. This airway dehydration stimulates the constriction of the bronchi and the thickening of mucous secretions causing mucous plugging and the patient may experience more difficulties breathing. 

On the other hand, overhydration is also a problem that may exacerbate negative pressure around the lungs, forcing leakage of capillary fluids which in turn promotes pulmonary oedema (fluid in the lungs) .6 Therefore, the maintenance of fluid level is an important factor in managing asthma attacks. 

Dehydration plays a significant role in treating asthmatic patients as the lack of water vapour in the lungs causes constriction of air passages and the production of mucus. Production of histamine is enhanced when a person is dehydrated which triggers an allergic reaction and aggravates asthma. Therefore, hydrating is an important part of the management of asthma attacks.

Why is hydration important for asthma?

Increasing fluid intake can help to maintain a healthy weight and improve psychological mood.7-10 As dehydration causes dryness of airways that can not only result in asthma but also other symptoms like nausea and headache, the best way to prevent this is to maintain an adequate water intake. This helps to moisten and filter the air before it enters the lungs.11

Asthma triggered by exercise can also be managed by hydration. During exercise, people tend to inhale air through the mouth, which causes dry air to enter the lungs which can trigger asthma symptoms. Here, hydration and breathing through the nose play a vital role in managing exercise-induced asthma12 as they can moisten the air passages and reduce the risk of asthma attacks.

By hydrating and maintaining a proper water balance in the body, the movement of fluids between the vascular compartment, airspaces and the interstitium of the lungs is promoted significantly and contributes to a proper clearance of airways.13 They also promote the formation of a thin layer of surface liquid in the airways which could capture foreign substances by humidifying the inspired air and also ease the mucociliary clearance of airspaces.

How can asthmatic patients stay hydrated?

To keep the body hydrated, a fluid intake of about 2-3 litres per day is recommended. The fluids to be taken include water, milk, soups, tea and coffee. Try drinking water even before you feel thirsty by making it a habit when you wake up before you go to sleep and before each meal. Another tip for keeping yourself hydrated is to take a water bottle along with you wherever you go or set a reminder to drink water at regular intervals of time.14

Asthmatic patients should drink at least 10 glasses (about 8 ounces each) of water daily along with a pinch of salt, as sodium helps to regulate the water level in the body.  Home remedies for asthma include drinking hot water and steam inhalation. Normal water may contain allergens that may worsen the conditions of asthma patients so they are always advised to intake purified water. Water purified by a reverse osmosis system is found to be free of pollutants and allergens that trigger asthmatic attacks. Drinking hot water can help prevent clogging caused by mucus and eases breathing.15

Steam inhalation and steam bath can be useful as they promote the clearance of airways and ease to breathe. Consuming a small amount of caffeine by drinking tea or coffee can improve lung function for up to 4 hours and can potentially reduce the risk and frequency of asthmatic attacks.16


Hydration is crucial for managing the symptoms asthma. Too low of a water intake causes dehydration and dryness of air passages, whereas overhydration may result in increased pleural pressure and swelling of the lung cavity. Therefore, it is essential to maintain a proper water balance by drinking adequate amounts of water as and when needed by following the tips discussed above. 

“Keep yourself Hydrated to stay Healthy”


  1. Lugogo, N., Que, L.G., Fertel, D., Kraft, M., 2010. Asthma. In: Mason, R.J., Broaddus, V.C., Martin, T.R., (Ed.) Murray & Nadel's Textbook of Respiratory Medicine. Saunders Elsevier, Philadelphia. 5th Edn. pp. 258-267.
  2. Brozek, J.L., Bousquet, J., Baena-Cagnani, C.E., Bonini, S., Canonica, G.W., Casale, T.B., 2010. Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines: 2010 revision. J. Allergy Clin. Immunol. 126(3), 466-76. 
  3. National Asthma Education and Prevention Program Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma. Rockville, MD. National Heart, Lung, and Blood Institute, US Dept of Health and Human Services, 2007. NIH publication 08-4051.
  4. Wechsler, M.E., 2009. Managing asthma in primary care: putting new guideline recommendations into context. Mayo Clin. Proc. 84, 707-717.
  5. Fanta, C.H., 2009. Asthma. N. Engl. J. Med. 360, 1002-1014.
  6. Kalhoff, H. 2003. Mild dehydration: A risk factor of broncho-pulmonary disorders? European journal of clinical nutrition 57, (12): S81-7
  7. Gabriel SE & Boucher RC (1997): Ion channels. In The Lung. Scientific Foundations. 2nd Edition, eds. RG Crystal, JB West, pp 305–318. Philadelphia: Lippincott-Raven Publishers.
  8. Manz, Friedrich, and Andreas Wentz. 2005. The importance of good hydration for the prevention of chronic diseases. Nutrition reviews 63, (6) (06): S2-5,
  9. Moloney E, O'Sullivan S, Hogan T, Poulter LW, Burke CM. Airway dehydration: a therapeutic target in asthma? Chest. 2002;121:1806-1811.
  10. Guidelines for staying hydrated communication. Dietitians Canada
  17. Fanta, C.H., 2009. Asthma. N. Engl. J. Med. 
  18. 360, 1002-1014.
  19. Fanta, C.H., 2009. Asthma. N. Engl. J. Med. 360, 1002-1014.Bonini, S., Canonica, G.W., Casale, T.B., 2010. Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines: 2010 revision. J. Allergy Clin. Immunol. 126(3), 466-76. 

Pavithra Saravanan

Pharmacist, MA Pharmacy, The Tamil Nadu Dr. M.G.R. Medical University, India
Pavithra Saravanan is a pharmaceutical professional and member in TOPRA. She completed her masters in pharmacy in Pharmaceutics department from The Tamilnadu Dr.M.G.R.Medical University, India. Pavithra has 2 years experience in Drug Regulatory Affairs, is equipped with knowledge in Clinical Data Management and Drug Safety and is currently working in the United Kingdom.

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