Eat carbs to support your immune system during exercise: study

We’re sorry, this feature is currently unavailable. We’re working to restore it. Please try again later.

Advertisement

This was published 7 years ago

Eat carbs to support your immune system during exercise: study

By Sarah Berry
Updated

When we are physically active, we spark a burst of internal activity.

Our hearts beat faster to pump oxygenated blood to our muscles, as our bodies need up to 15 times more oxygen we start to breathe faster, our blood sugars can drop as they are burnt as fuel, our hormones surge and some cells break down while new ones grow.

A banana may be good for your immune system during or after intense or long exercise.

A banana may be good for your immune system during or after intense or long exercise.Credit: iStock

It's a complex process that makes us healthier and stronger, lifting our body and our mood.

During the flurry of internal and external activity, however, it is also believed there is an "open window" where our immunity is weakened and, if we exercise again intensely during this time, we are more vulnerable to illness and infection.

Proper recovery is therefore considered necessary to prevent "overtraining syndrome" where, instead of feeling better from exercise, we are left feeling fatigued, our performance decreases, and we may suffer psychological and hormonal disturbances that can last for weeks or months.

To avoid this, how to make recovery from exercise more efficient and effective has interested researchers and athletes alike.

There are various approaches to recovery – for those who train regularly and intensely – including what to eat and when.

A new study by Queensland University of Technology researchers has found that having carbs during or straight after an intense workout could help your immune system to remain healthy.

"Among various nutritional strategies to counteract immune depression during exercise recovery, carbohydrates have proven the most effective," said lead author Dr Jonathan Peake. "Ingesting carbohydrates during vigorous exercise may help, because carbohydrates maintain blood sugar levels.

Advertisement

"Having stable blood sugar levels reduces the body's stress response, which in turn moderates any undesirable mobilisation of immune cells. However, more research is warranted to verify that this also helps to prevent infections and illnesses."

Interestingly, Peake and his colleagues suggest their findings also indicate immune cells do not always leave us "open" to illness and may instead move around the body during recovery, "patrolling" for where they are needed.

"People often have fewer natural killer white blood cells after a workout but we now believe they move to other parts of the body, rather than being destroyed," he explained.

"Exercise is a form of stress and more vigorous exercise creates more physiological stress, which causes physiological and biochemical changes in the body. To tackle the potential threats these changes highlight, the immune cells may simply move out of the blood stream to the lungs, for example.

"This still leaves our bodies vulnerable to infections and, generally speaking, the more strenuous the exercise, the longer it takes for the immune system to return to normal.

"Epidemiological evidence suggests that regular moderate exercise protects against upper respiratory illnesses, like the common cold, whereas regular intense exercise increases the risk of upper respiratory illnesses."

While moderate exercisers do not need to worry, he said the findings are targeted at those whose workouts are intense or endurance athletes who work out for 90 minutes or more.

"The consumption of carbohydrates before and during strenuous exercise not only improves endurance performance, but it can also minimise exercise-related immune disturbances," he said.

"Between 30 and 60 grams of carbohydrates every hour during exercise help to support normal immune function. Examples of carbohydrates that could be consumed during exercise include carbohydrate-containing fluids, gels and bars consisting of different carbohydrates such as glucose and fructose. Alternatively, bananas may also do the job.

"As general advice for people who train for and participate in endurance events, any products should be tested if they are tolerated in the field.

He added: "Consuming carbohydrates in the first few hours immediately after strenuous exercise also helps to restore immune function. This is especially important in situations where the recovery duration between two consecutive exercise sessions is short, which is often the case for athletes.

"A diversified and well-balanced diet is most likely sufficient to help maintain immune function following longer-term exercise training.

As well as consuming carbs – and a well-balanced diet in general – Peake said there was another way to support your immune system after exercise.

"Sleep is recognised as important for maintaining immune function," he said. "However, more research is needed to understand the influence of sleep on immunity in athletes."

What to eat before and after your workout

Before: Broad suggestions include more carbs (a banana or a smoothie) one to two hours before cardio or more protein (an egg, some nuts or meat) before strength training.

After: Within about 45 minutes of any intense workout, eat a mix of protein and carbs to replenish glycogen stores and muscle protein synthesis.

Examples of carbs

Sweet potatoes

Quinoa

Fruits (pineapple, berries, banana, kiwifruit, grapefruit, apples)

Rice cakes

Kidney beans

Rice

Oatmeal

Potatoes

Pasta

Dark, leafy green vegetables

Examples of protein

Animal or plant-based protein powder

Eggs

Beans

Almonds

Greek yoghurt

Cottage cheese

Lentils

Salmon

Chicken

Protein bar

Tuna

Most Viewed in Lifestyle

Loading