Intense exercise can cause blurred vision and dizziness in some people. As more energy is directed to the muscles and leaves the brain, the organs and senses are deprived or even go numb. You may find it difficult to keep balance. Exercise can also cause nausea, fatigue, thirst, shallow breathing and difficulties in concentration. If such a series of feelings occur, do not ignore them because you might have an underlying problem.

What Causes Blurred Vision After Exercise?

Hypoglycemia is a common cause. It may result from factors such as dehydration and depleted nutrients. Blurred vision may also be caused by environment factors such as wind, cold, allergies as well as irritation from sweat or sunscreen.

However, when you get blurred vision regularly and without an obvious cause, you need to see your doctor for a checkup because you might have a serious health problem. Vision problems may result from migraines and other conditions. People with MS (multiple sclerosis) may suffer from visual changes which worsen when body temperature rises. Blurred vision can also be caused by a rare condition in which the pigment in the iris of the eye is dislodged. Cardiovascular conditions may also cause blurred vision. For a pregnant woman, blurred vision may be a sign of preeclampsia in which the unborn baby may not be getting sufficient blood supply for survival.

How to Deal with It

The ways to deal with the problem of blurred vision depend on the causes and include the following:

• If blurred vision occurs during exercise, stop immediately and rest to enable your body to recover.
• If it is caused by an allergy, take an antihistamine or contact a doctor.
• If the blurred vision has arisen from low blood sugar, sip on water and take a snack containing about 15 grams of carbohydrate.
• If you are pregnant and get blurred vision, contact your doctor without delay.
• If your blurred vision is a result of an underlying problem, consult your doctor for professional advice.

How to Prevent Blurred Vision After Exercise

Because hypoglycemia is the main cause of blurred vision, by preventing low blood sugar you avoid blurred vision. However, this can only work when any underlying problem has been dealt with.

Taking breakfast or a snack before working out is one of the easiest ways to maintain supply of energy throughout your exercise session. Choosing endurance training in place of strength training reduces the likelihood of hypoglycemia because fat is burnt for fuel during endurance training, unlike in strength training where the main source of energy is glycogen.

When you follow a routine of both endurance and strength training, the recommendation is to start with moderate endurance exercises for 20 to 30 minutes, at 60 to 70 percent of your maximum heart rate. Thereafter you can get into the intense strength training for the final 15 to 20 minutes. After the workout, it helps to take a snack such as a glass of orange juice, a small banana or some figs.

How to Prevent Hypoglycemia After Exercise in Diabetics

If you have diabetes and take insulin or other blood-sugar-lowering medicines, you have a high risk of hypoglycemia and blurred vision after exercise. But you can prevent it in the following ways:

• Before exercise, take your blood sugar reading to ensure it is sufficient. Take a snack if required.
• Avoid alcohol before or after working out.
• Do not exercise during the peak period of your insulin action.
• Avoid exercise in the late evening and ensure you complete exercising at least 2 hours before going to bed.
• Keep off saunas, steam rooms and hot tubs soon after exercise. These may maintain your high heart rate and lower your glucose level.
• Exercise not more than once or twice per day. More sessions increase your risk of hypoglycemia.
• Observe regular timing for insulin injections.
• Take your blood sugar reading after exercise to prevent hypoglycemia from occurring some hours later. It is advisable to check your blood sugar levels several times in 2-4 hours following exercise. Note that intense exercise may lead to low blood sugar for up to 24 hours after exercise.

When Blood Sugar Is Less Than 100 mg/dl Soon After Exercise

• Keep to post-workout snack guidelines to avoid blurred vision after exercise. If you are not due for a meal or snack for the next hour, take 15 grams of carbohydrate snack to prevent low blood sugar. If you are not due for a meal for more than one hour, take a snack of 15 grams carbs and 7 to 8 grams protein.
• Increase your carbohydrate intake before exercise.
• Reduce your dose of active insulin for the following exercise session.
• Consider reducing your insulin dosage after exercise.
• If your blood sugar level at bedtime remains below 100 mg/dl, take a double portion of your bedtime snack or reduce your dose of bedtime insulin.

In Case of Unplanned Exercise

In some instances, unplanned physical exertion or exercise may be inevitable. In such cases, you may need additional food to maintain a healthy balance between insulin or other medications and your energy needs. This will be determined by several factors including the following:

• A snack is necessary if the physical activity begins after 2 hours or more following your last meal.
• A snack is necessary if the exercise lasts for more than one hour.
• Long lasting or day-long activities may call for adjustments of snacks and insulin routines.
• In case you are working on losing weight, it is advisable to adjust your insulin or other medication instead of taking extra food.

In addition to these tips on blurred vision after exercise, consult your diabetes management doctor for advice on the best way to exercise and manage your diabetes.