Food and training to support immunity

Immunity is something that everyone is thinking about at the moment with the spread of COVID-19 virus. Here I share some practical advice and recent research on running and effectively supporting your immune system.

Adjusting your training

The amount and intensity of exercise you take affects immunity and your risk of infection.
But the relationship is not a simple straight line. Increasing exercise intensity and duration reduces risk of infection up to a point. Then the relationship changes and doing more running actually increases your risk infection due to lowered immunity.

This is called a J curve, which looks something like this:

Regular modest exercise, be that running or another other activity, increases immune function and so decreases risk of infection of viruses. There is plenty of evidence to support this.
Taking regular exercise is wonderful for a healthy body and a healthy mind, both of which are very important right now.

However, there comes a point where the curve shifts upwards, to it the J shape.
Studies have shown that high-intensity, long-duration exercise, like running marathons and ultra marathons can lower immune function for 24 to 72 hours after. Which can result in greater likelihood of coming down with colds and respiratory illness, and increase your risk of infection from flu viruses.

Essentially, more exercise at the moment is not necessary better.

How much is too much?

Well, everyone is different, we all have different training statuses, age, stress levels and many other factors.
There is not an exact number of miles or minutes of running to stick within before your immunity decreases.
One study does however suggest an easy to remember 60/60/60 rule that suits most of us:
Run less than 60 miles a week, mostly at a low intensity (60% of max VO2 corresponds to 75% of max heart rate), mostly in workouts that are less than 60 minutes at a time.

Intermittent running also seems to help reduce risk.
Following a run/walk or minutes hard/minutes easy approach to running training has been shown to maintain immune function.
Runners of all abilities can factor this guidance into long training runs. 

What is the best food to eat?

Get the balance right. Which is something I say all the time to my nutrition clients.
Research shows that low-carb diets and ways of eating are not generally beneficial for endurance runners. In fact, eating insufficient carbohydrate can reduce immune function, increasing risk of infection.
One study has reported healthy immune cells in runners who consumed carbohydrate during a 3-hour run, but compromised immune cells in those runners who did not consume any carbohydrate during the 3-hour run.

In addition to regular carbohydrate foods (oats, rice, potatoes, whole grain bread and other less processed carbs), runners need to be eating plenty of colourful vegetables and fruits for their vitamin C, phytonutrient and antioxidant properties. Plus regular quality protein and sufficient fluids.
Essentially, a balanced diet is vital.

Lifestyle advice

A final few words on lifestyle strategies to support immune function and training.
This is the top piece of advice for everyone.
There is so much research to support quality sleep improving immune function by reducing stress. And don’t forget that exercise is a form of stress.
If you are feeling anxious about the coronavirus, worried about family and finances, plus training hard (maybe out running once a day but also doing HIIT and strength workouts at home) it is likely that stress chemicals in your body are increased.
Sleep is vital to reducing stress. It could be that, for the moment at least, intense training takes a back seat, replacing instead with more calming activities. This will support your immune function and hopefully keep you healthy.

Nutritional Therapy is an evidence based practice, helping people achieve optimum health and athletic performance. In my Surrey nutrition clinic I work with people on an individual basis, looking at current diet and lifestyle and working to support and guide clients with personalised, achievable nutrition plans. 

For more information contact me, Helen Morton, registered Nutritional Therapist based in Godalming, near Guildford in Surrey.

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