Can Pollen Allergies Cause Fatigue?

Do you suffer from hay fever? Around 10-30% of the global population deals with seasonal allergies, known as hay fever (clinically referred to as allergic rhinitis) [source: Schmidt]. It typically starts in the spring when trees bloom and release pollen. Pollen, a fine powder produced by male conifers (cone-bearing plants) and flowering plants, plays a crucial role in plant reproduction. Sometimes called flower sperm, it carries male gametes (reproductive cells) to the pistils (female parts) of the same or other plants of the same species, facilitating fertilization and seed production. Pollen is carried by wind or insects like bees, but it also triggers allergic reactions in many people who inhale it.

How can pollen make you feel tired? When the body encounters allergens, it produces histamine, which can cause inflammation in the nasal passages. This leads to symptoms like nasal congestion, sneezing, and a runny nose, all of which disrupt sleep. A study revealed that the more severe someone's hay fever, the more likely they are to have sleep disturbances [sources: Leger, et al., National Sleep Foundation]. Sleep deprivation often leads to fatigue and difficulty focusing at work or school. Many allergy sufferers also experience irritability and depression. Researchers are still unsure whether these mood changes are part of the allergy symptoms or caused by lack of sleep.

Another reason you might feel fatigued during "pollen season" is due to the allergy medications you take. Antihistamines work by easing the symptoms of a runny nose and watery eyes, calming the histamine response your body triggers when fighting allergens. While older antihistamines like Benadryl are well-known for causing drowsiness, even newer 24-hour antihistamines such as Allegra, Zyrtec, and Claritin state on their labels that drowsiness could occur as a side effect. Some individuals are more sensitive to this, and certain medications may make you feel sleepier than others. For instance, Zyrtec causes drowsiness in one out of every six users, though it works faster than the other two [source: More].

If your seasonal allergies are affecting your sleep, try staying indoors during the day to reduce exposure to pollen, and use nasal strips at night to open your nasal passages. It's also a good idea to consult your doctor about your sleep troubles, as they may suggest changing your antihistamine medication. By properly managing your allergies, you'll improve your sleep quality.