As the hay fever season kicks off, the UK's 15 million sufferers could be forgiven for worrying about the prospect of months of sneezing and watery eyes as they battle their allergy.
However, aside from keeping away from pollen, new research suggests that avoiding stress, and following other healthy habits including eating a good diet and exercising could reduce symptoms for hay fever sufferers.
Adopting a healthier lifestyle could make a vital difference to millions of people afflicted by hay fever: A staggering 78% of them say the allergy has a negative effect on their quality of life.
The hay fever season is just starting - the birch pollen season began this week, affecting around 25% of hay fever sufferers, the grass pollen season, which affects around 95% of sufferers, begins in late May, and oak pollen and weeds such as nettles will affect 20% of sufferers in May.
The new Kleenex Hay Fever Health Report 2010 surveyed more than 2,000 sufferers to find out how their lifestyles affected symptoms, and found that those with the highest stress levels reported the most severe problems.
Nearly three quarters (71%) of those who said they were stressed all the time, described their symptoms as unbearable or uncomfortable.
This could be due to the release of the stress hormone cortisol, which can dampen the immune system, thus enhancing and prolonging hay fever symptoms.
While regular exercise can help boost the body's immunity, only one in five hay fever sufferers get the recommended amount of exercise.
And those who rated their diet as healthy were the most likely to have mild symptoms, whereas two thirds of those who said their diet was poor had unbearable symptoms.
The report was written by Professor Jean Emberlin, director of the National Pollen and Aerobiology Research Unit (NPARU).
She says: "There is clear evidence that the way hayfever sufferers live their lives can either exacerbate or reduce the severity of symptoms.
"Poor diet, a lack of exercise and high stress levels can all increase suffering, but the lack of awareness of the impact these factors have on hay fever means many sufferers may unwittingly be making their symptoms worse."
Emberlin says that while it wasn't particularly surprising that stressed people get worse hay fever symptoms, she didn't anticipate how little exercise hay fever sufferers did.
"Whether it's because they don't like exercising when they have these symptoms, I don't know.
"Considering hay fever is at high prevalence in the younger age group, I was surprised there wasn't more activity - generally if you exercise you feel better."
As well as causing personal problems, it's estimated that the lower levels of concentration and productivity experienced by hay fever sufferers costs UK businesses over £7 billion annually.
In addition, research shows that students with hay fever can drop a grade if there's a high pollen count on the day of an exam.
Non-sufferers who believe hay fever isn't relevant to them may have to think again in the future, as over the next 20 years the proportion of hay fever sufferers in the UK is predicted to rise from 20-25% of the population to 45%.
The rise will be due to factors including climate change, which will affect the timing and severity of pollen seasons, and stressful urban lifestyles.
The report warns: "Such a hefty climb in hay fever rates means non-sufferers may soon find they are no longer immune to hay fever."
The allergy can develop at any age, and usually causes sneezing, a runny nose and itchy eyes, with an itchy nose, runny eyes and an itchy throat or mouth also reported.
Elisabeth Field, 35, has suffered from hay fever since she was a child, and says her symptoms of watery, itchy eyes, sneezing and a blocked nose have started this week.
She knows she's allergic to long grass, but developing symptoms now suggests that she may also be reacting to tree pollen.
Field, who lives in London, says: "It's worse this year than it has been for years.
"Yesterday my eyes were streaming all day, and it means I can't wear my contact lenses. It's so annoying."
She says she has not noticed that stress affects her symptoms, but she exercises and eats a good diet, which may help, along with the over-the-counter anti-histamines she takes.
"This year my hay fever has really kicked in with a vengeance - it's been like I've gone to another planet. It really makes a difference to my life, making it a lot more uncomfortable and awkward."
Field says her symptoms are much worse in the city than in the countryside, a reaction which is borne out by research which has found there's a 15% higher incidence of hay fever in cities than in rural areas.
And as Britain's urban population is expected to grow by 9.1 million in the next 20 years, that means as many as 32 million Britons could suffer from pollen allergies by 2030.
Emberlin explains that there's a higher incidence of hay fever in urban areas because air pollution affects pollen and makes it more allergenic.
"People often think that urban areas are like a haven to get away from pollen, but they're not.
"Trees in urban areas can have more allergenic pollen. It's a known phenomenon."
This happens because nitrates in vehicle exhausts, and some other agents, alter the protein structure of the pollen grains and makes them more potent.
"So you need less pollen to cause the reaction to trigger the hayfever," explains Emberlin.
Some people may not realise they have hay fever if it's tree pollen they're allergic to, as some tree pollen counts are only high every four or five years, and they may have no symptoms in the low count years.
"That's part of the problem," says Emberlin.
"If people are allergic to grass pollen, they usually realise what it is.
"It's the weeds and the trees and sometimes fungal spores which can give people hay fever symptoms and they don't realise what's causing it."
The vast majority of hayfever sufferers (86%) are unsure which type of pollen they're allergic to, but Emberlin stresses that it's useful for people to know what they're allergic to so they can avoid the triggers.
She recommends that people keep a diary of when their symptoms occur, what the weather was like, and where they've been, and match it against the pollen calendar on the Pollen UK website ( www.pollenuk.co.uk ).
"If you've got hayfever, it's best to be prepared with the comfort things that can help, as well as the treatment, and know the pollen count and forecast," she advises.
"That can help people manage symptoms much more effectively."
She adds: "Although hayfever isn't in itself life-threatening, it does cause a lot of economic and social problems.
"It's not something people should treat in a trivial way."
Lifestyle tips for sufferers
Follow Professor Emberlin's advice:
- Try to reduce your stress levels - take regular exercise, spend time with people who don't cause you stress, and look after yourself physically.
- Don't stop going outside completely, just avoid times when the pollen count is highest - for grass pollen, usually first thing in the morning and early evening.
- Outside, be prepared by carrying tissues, a bottle of water and your medication or treatment.
- Don't hang clothes outside on high pollen count days because pollen will cling to the fabric.
- Eat a balanced and varied diet to support your immune system.
- Avoid cigarettes and smoky environments as the smoke irritates your respiratory passages and nose.
- Reduce your alcohol intake during the hay fever season. As well as making you more sensitive to pollen, alcohol also dehydrates you, making symptoms seem worse.
- Wearing sunglasses and a broad-rimmed hat can help keep pollen away from your face.
- Consult your GP or pharmacist about the best medication or treatments.