Diabetes sufferers should munch some carbohydrates before rigorous physical activity such as heavy-duty swimming, walking – or even sex.

At least, that’s according to Dr David Cavan writing in his new book, Take Control of Type 1 Diabetes.

“Sex carries a risk of hypoglycaemia (low blood sugar levels),” Dr Cavan wrote.

“So, having a supply of carbohydrate at your bedside to take before, during or afterwards is a good idea.

“Diabetes type 1 is the third partner in a sexual encounter, and needs to be treated with respect by both the other partners.”

Diabetes.co.uk said type 1 and type 2 diabetes sufferers should take several precautions to help maintain your blood sugar levels during rigorous exercise.

They recommend eating a carbohydrate snack before exercise to maintain sugar levels.

You should also eat “extra” carbohydrate snacks if you are planning to do long duration or high intensity activity, such as football, hiking, biking or skating.

The website recommends taking a “fast-acting carbohydrate food” like a glucose tablet with you when exercising.

If blood sugar levels drop too low you should take this to help restore the original level.

Failing to take adequate precautions before rigorous exercise, such as sex, can cause blood sugar levels to drop too low.

This risks damage to vital organs and could cause seizures, rapid heart beat, clammy skin and loss of consciousness.

The condition, known as hypoglycaemia, could also cause damage to the reproductive organs.

“Sex is one of the bodily functions that can be affected by nerve damage due to blood sugar levels,” wrote Dr David Cavan.

“While erectile dysfunction is well known as a complication of diabetes in men, it is less recognised that women can also experience sexual problems.”

According to medical website Healthline, good carbohydrate snacks to take include almond nuts, roasted chickpeas and cheese with whole grain crackers.

“The key is to choose snacks high in fibre, protein and healthy fats,” they said.

“It’s also important to snack on nutrient-dense foods that promote overall health.”

You could also slash blood sugar levels by adding different foods to your diet, such as red onions.

“Garlic and onions may help to lower blood sugar levels, making them beneficial for people with insulin resistance or diabetes,” said Dr Sarah Brewer and Juliette Kellow, nutritionist.