When Are Allergies Worse During The Day

This is scenario that most of those that suffer from allergies and hay fever in particular, are familiar with. Even before any grass is growing, before any pollen is seen in the air, the symptoms are already present. However, interestingly, with regards to the severity of the symptoms, most patients report a pattern during the day. Morning is most definitely the worse, with symptoms ranging from heavy sneezing to nasal congestion. During the day, however, the symptoms seem to give the sufferer some relief, only to come back again in the evening.

The reason for this diurnal pattern isn’t entirely obvious, as the pollen and other allergens do not become less allergenic as if by miracle during the day. This article will review current theories to explain this rhythm and provide some suggestions to maximise treatment.

Does it matter when to take allergy medication?

Hay fever is a familiar type of allergy, even for those that luckily don’t suffer from this condition. Symptoms include rhinitis, coughing and sneezing, watery and itchy eyes and blocked nose. All allergies are characterized by an over-reaction from the immune system, which triggers an inflammatory response in the form of histamines. These chemicals will then interact with a variety of cells in our body to create the much dreaded symptoms.

The most common allergy treatment involves taking antihistamines, which block histamine receptors and therefore means histamine cannot trigger an allergic response. From this, it is easy to see that the best time to take these drugs is before our system is overwhelmed by histamine. So, when should you take your medication?

Do allergies have a diurnal variation?

To answer this question, let’s analyze in a little more detail, this pattern experienced by so many hay fever sufferers. In 1973, two scientists decided to investigate this phenomenon and asked 2000 patients in the UK about their allergies, what symptoms they experienced and more importantly in this case, when was their allergy worse. With no room for doubt, most participants reported worse symptoms in the morning and evening, with some improvement during the day. More recent studies also validate these findings. This immediately raises some questions: What happens during the day to improve the condition? Is it related to the environment or to the body metabolism?

Why is it worse in the morning?

Although this circadian pattern has been identified, the mechanisms that explain why this happen this way have not been completely unveiled. It’s more than likely that it’s not just one factor, but a combination of factors that result in the worsening of symptoms experienced in the morning.

Theory 1: More pollen in the morning

The first obvious target to consider is the pollen, which is at its highest during the morning. Some doctors suggest the symptoms are worse during the morning and evening because the pollen is released in the morning, rises in the atmosphere during the day, but cools down and drops in the evening. However, this does not explain why certain patients that work night shifts, still experience “morning-like” symptoms independently of when they wake up.

Theory 2: Overactive immune system

The second theory defends that this diurnal pattern is regulated mainly by our body and is not dependent on the environment, or in other words, it doesn’t reflect pollen variations during the day. This is particularly obvious in those patients that have to sleep during the day and work at night. Even then, the worst part of the day is after waking up, which is not explained by a pollen peak in the atmosphere. This may be due to a hyperactive immune system during the night, which then continues to overreact to allergens immediately after waking up. As the day progresses, the immune system is toned down and the allergic reaction is diminished.

Theory 3: Lack of movement

Another interesting theory involves lack of movement in the morning. These days, many of us spend the first few hours in the morning in a car or public transportation to get to work. This involves very little exercise and only contributes to worsening the symptoms. To obtain some relief, many sufferers report that simply walking is enough to ease some of the symptoms. Unfortunately, this is only a temporary reprieve, and when you sit down again, symptoms return very quickly. This may be explained by a temporary improvement in blood circulation in the affected areas, possibly because you’re more likely to take deep breaths as you walk.

Theory 4: Shallow breathing during sleep

A final possibility concerns our breathing rate while we sleep. Our body naturally lowers breathing rate during the night, which means any nasal blockages cannot be cleared properly. As you wake up, it’s the sign for your body to clear the airways and sneezing is a very effective way to achieve this.

Why is it worse in the evening?

Similarly to understanding why is worse in the morning, we don’t fully know why it’s worse in the evening as well.

Theory 1: Less cortisol

It’s been shown that several components of the body’s anti-inflammatory mechanism, including cortisol, have a circadian production, with a drop visible in the evening that usually lasts all night. This means there’s no defense against your over-active immune system and histamine release increases. This may explain what symptoms get worse in the evening and many hay fever sufferers report difficulty sleeping.

Theory 2: High pollen density

During the day, pollen is maintained in suspension in the atmosphere by the warm air. However, as the night approaches, temperature starts to drop and so does the pollen. This increase in pollen would explain the deterioration of the symptoms towards the evening, however even in patients that remain indoors, protected from the rising pollen levels, this decline is still noticeable.


Although the exact mechanism has not been identified yet, leaving much room for speculation, the most important conclusion to take from this is, in order to maximize the benefits from your medication, the best time to take any drugs is immediately your body is saturated with histamine. This means early in the morning and then again in the evening. This circadian pattern has now been identified in many other conditions, giving rise to a new discipline to assess when treatment is supplied to patients. This is called chronotherapy and defends that treatments should only be supplied when they’re going to have the most significant effects.


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  1. My theory for why allergies get worse in the evening is simple; the body is tired and when it is run down, the human body cannot defend against foreign particles as well. Sleep has often been my only way to get be fully recovered. A heatpack on my sinuses has been the only way for the pain to subside enough to sleep. However term taking probiotics and eliminating/reducing gluten & sugar & dairy has greatly improved my overall ability to withstand high pollen days, such as today.

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