Run Well Juliet McGrattan (microsoft ebook reader TXT) 📖

is a particular problem for contact lens wearers). Sun cream or sweat running into the eyes can also cause irritation. If something flies into your eye and scratches the cornea, even if it flies out again, it can cause some discomfort and altered vision. This is called a corneal abrasion and while our eye lashes and tears are designed to protect our eyes, sometimes the unexpected happens on a run, particularly on a breezy day. Excess tears in the eyes can cause blurred vision too.

If your blood pressure is unusually low and making you feeling faint, then you might have less blood flowing to the part of your brain which controls vision and may experience some blurring as a result. People often cite low blood sugar as a possible cause of blurred vision, but this is unusual unless you are a diabetic on medication that puts you at risk of hypoglycaemic (low blood sugar) attacks. Blurred vision, an area of darkness or some zig-zag lines in your field of vision are typical symptoms of a migraine aura. It may or may not develop into a full-blown migraine.

While all these causes are reversible and unlikely to cause permanent damage, it’s important to know that blurred vision can be a sign of something more sinister. If it’s associated with floaters (black specs floating around like dust in front of your eyes), flashes of light or a curtain appearing to block off some of your visual field, then this is potentially a detachment of your retina and you need to seek an urgent medical assessment as this can cause permanent damage to your vision. Similarly, a stroke that affects your eye can present with a change in vision in one eye. It can become double or blurred or you may lose sight completely. If a stroke affects the visual centre in the brain, then it may cause these changes in both eyes simultaneously. You may or may not have other symptoms of a stroke.

A rarer cause is a condition called optic neuritis where the optic nerve, which carries information between the eyes and the brain, becomes inflamed. If you have optic neuritis it may become apparent after a run, with reduced, blurred vision and pain in the eye, especially when you try to move it in different directions. Optic neuritis needs to be diagnosed and investigated by a specialist to ensure no other medical conditions, such as multiple sclerosis, underlie it.

Blurred vision that develops slowly over time can have many other causes that aren’t directly related to running. Don’t try to self-diagnose. If you have new visual changes then get assessed. If you suspect a stroke or a detached retina, then these are medical emergencies and you should go to Accident and Emergency. If you have a mild or recurrent problem, then see your optician or GP.

Real-life runners

Being a guide runner – someone who supports a visually impaired runner by guiding them, usually by running alongside them – has been a wonderfully enriching and joyous experience for me. I’ve made great friends and learned so much about what it means to live with a disability. Why not give it a go? The most important thing is to listen carefully to what your runner wants and needs from you.

Dr Simon Tobin, GP and parkrun ambassador for health and wellbeing

Q Exercise seems to be good at preventing so many diseases. Does it help prevent eye ­disease too?

A Reading about blurred vision above you might feel a little worried that exercise is bad for your eyes, but in fact it’s quite the opposite! Exercising regularly can help protect your eye health. Many serious eye diseases are linked to high blood pressure, high cholesterol and diabetes, which exercise is well known to help either prevent or manage. Take glaucoma, for example, a leading cause of blindness worldwide, where pressure builds up inside the eye. Some studies have shown that exercise may lower the pressure inside the eye. One study done in 2017 found that moderate to vigorous exercise might be particularly beneficial. The participants who were the most physically active had a 73 per cent lower incidence of glaucoma than the least active. For every 10-minute increase in this type of physical activity per week, the risk of glaucoma decreased by 25 per cent. If you already have glaucoma, then vigorous exercise may not be suitable for you, so please check with your ophthalmologist. Similarly, several studies found that people who exercised were less likely to develop a common eye condition called age-related macular degeneration (AMD) than those who were sedentary and didn’t exercise. The macular is part of the retina at the back of the eye. When it degenerates central vision is lost and the periphery is spared, so although you don’t lose your vision completely it can be very debilitating. There is still much we don’t understand about the link between the two, but it seems clear that we can add eye health to our list of reasons why we run.

Headaches

Q Why do I get a headache after I run?

A Safety first. If you get a severe, sudden onset of a headache during a high intensity workout, where you feel as if someone has hit you over the back of the head, then this is a medical emergency. This could be a burst blood vessel in the brain causing a subarachnoid haemorrhage (SAH), where blood bleeds onto the surface of the brain. SAH is more common over the age of 50 and happens when small swellings on blood vessels, called aneurysms, burst. The severe headache may be associated with vomiting, double vision or even a loss of consciousness. It is a type of stroke so you should dial 999 for an emergency ambulance.

What is much more common, however, is a headache which starts when you come back from a run or even later that day. There are lots of reasons why this can happen and thankfully most of them are reversible,