How to Prevent and Manage Hypoglycaemia During Exercise

Exercise is fantastic for managing diabetes, but if you’re taking insulin or certain diabetes medications, you might have experienced (or worried about) a hypoglycaemia, or low blood sugar, during or after physical activity. Let’s break down why exercise can cause hypos, what symptoms to watch for, and how to move safely and confidently.

Why Does Exercise Sometimes Cause Hypos?

When you get moving, your muscles use more glucose from your bloodstream for energy. If you’re on insulin or certain diabetes medications, this extra demand can sometimes lower your blood sugar too much especially if you haven’t adjusted your medication, meals, or snacks.

• You take insulin or insulin secretagogues (certain oral diabetes tablets)
• You exercise for a long time or more intensely than usual
• You skip a meal or snack before activity
• You drink alcohol before or after exercise
• You exercise late in the evening

Checking your blood sugar before getting active is key to preventing hypos. It’s also a good idea to chat with your diabetes care team (doctor, nurse, dietitian, or pharmacist) to find out your personal risk and get tailored advice on adjusting your insulin, tablets, or snacks around exercise.

WHAT DOES A HYPO FEEL LIKE?

Everyone’s different, but common signs of a hypo include: (If you’re not sure, it’s always best to check your blood sugar)

• Shakiness, sweating, or feeling clammy
• Dizziness or light-headedness
• Hunger
• Tingling lips
• Weakness or tiredness
• Irritability or mood changes
• Blurred vision
• Confusion or difficulty concentrating

HOW TO PREVENT HYPOS WHEN EXERCISING

1. Check your blood sugar
   Test your levels before, during, and after exercise, especially if you’re trying something new, going longer, or upping the intensity.
2. Have a plan
   Before starting a new fitness routine, talk with your healthcare professional. Your healthcare team can help you balance your medication, food, and exercise so you can move safely and confidently.
3. Don’t skip meals or snacks
   Eat regular, balanced meals and snacks. If your blood sugar is on the lower side before you start, have a small carbohydrate snack (like Glucochews, fruit, or crackers).
4. Carry hypo treatments with you
   Always have fast-acting glucose (e.g. Glucochews) on hand, whether you’re at the gym, out for a walk, or playing sport.
5. Wear medical ID
   Consider wearing a diabetes ID band, especially during longer or solo activities.
6. Listen to your body
   If you start to feel “off,” stop and check your blood sugar. Don’t push through symptoms.

WHAT TO DO IF YOU HAVE A HYPO DURING OR AFTER EXERCISE

Hypos can happen during, straight after, or even hours following exercise. Especially if you’ve skipped a meal, worked out longer or harder than usual, or taken insulin/insulin secretagogues. If you experience a hypo during or after exercise, treat it immediately using the “15-15 rule”:

1. Check your blood sugar.
2. If your reading is 5.5 mmol/L (100 mg/dL) or lower, have 15–20 grams of fast-acting carbohydrate to raise your blood sugar. This could be:
   1. 4 Glucochews
   2. Half a cup (125 mL) of juice
   3. 1 tablespoon of sugar or honey
3. Wait 15 minutes, then check your blood sugar again. If it’s still below 5.5 mmol/L (100 mg/dL), have another 15 grams of carbs. Keep repeating every 15 minutes until your blood sugar is safely above 5.5 mmol/L (100 mg/dL).
4. Take a break from your workout to treat the hypo and only resume once your levels are back up and you feel well. If you want to continue your workout, make sure your blood sugar is back above 5.5 mmol/L (100 mg/dL) before starting again.

WHEN SHOULD YOU TALK TO YOUR HEALTHCARE TEAM?

If you’re finding that low blood sugars are interfering with your activity, don’t hesitate to reach out to your diabetes care team. Your provider will help you find the best plan for your unique needs, and they may suggest:

• Eating a small snack before you exercise
• Adjusting your medication dose
• Or a combination of both, especially for longer or more strenuous sessions

A FEW EXTRA TIPS

• Keep a record of your exercise, blood sugar readings, and how you felt—this can help you and your healthcare team spot patterns and make adjustments.
• Hydrate well and look after your feet with supportive shoes and regular checks.
• Start small and build up, every bit of movement helps!

Explore our blog for more tips and resources on diabetes management.