Oh Madhu, I forgot to tell that it is best to exercise indoors if you have pollen allergy. But since you have to run a marathon, then I suggest you take these precautions:
* Try not to exercise outside when the pollen is at it's highest - the early to mid-morning hours. Exercise in the evening hours or after a rain, which washes pollen out of the air.
* Inhale through your nose when you exercise. When you inhale through your nose, you warm the air (especially important for asthmatics). Cold air constricts smaller air passages, and this can mean less air, less oxygen delivered to our cells. Your nose is also lined with hair that can help to filter some of the smaller microscopic particles.
* Take your allergy medication everyday, or as needed allergy medication (such as an oral anti-histamine pill) a few hours before you go outside.
* Wear wrap-around sunglasses to decrease the amount of pollen that gets into the eyes.
* Consider wearing a mask or bandana to decrease the amount of pollen that gets into your nose and lungs.
* Carry a clean towel with you to wipe any sweat (and pollen) away from your face during exercise.
* When finished exercising, shower immediately and put your exercise clothes in the wash (they're likely to be covered with pollen).
* Eat some good fat! Cold water fish like salmon contains important omega-3 fatty acids that help inhibit the inflammatory response which is known to cause runny noses and teary eyes in response to harmless allergens.
* Eat your fruits and veggies. Many studies suggest that antioxidants like Vitamin C and bioflavonoids help suppress the inflammatory response. Raw pineapple contains the anti-inflammatory enzyme Bromelain.
All the best for your half marathon, Madhu!! đ