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Protecting Your Immune System During Outdoor Workouts

man holds plank outdoors scaled

Just as it felt like Spring was here to stay, in come strong winds, rain and a week-long storm to remind us winter is still with us. Did you know that if you’re someone who works out on a very regular basis, especially in all weathers, you could be more prone to picking up whatever is going around? 

How do we stay healthy? Good food and water, right? That’s true, but you may need a little more help. 

Will Girling, performance nutritionist at the Eastnine fitness app discusses how we can prevent depleting our immune system to protect ourselves while we work out, out in the cold and rain. 

Vitamin D3

During gloomier weather, and even on some sunnier days, we’re unable to get enough of the direct sunlight from the sun to provide us the Vitamin D3 we need to synthesise 25(OH) the active form of vitamin D that helps fight against illness.

Can we not get it through our diet? You can get it through some food sources such as salmon – oily fish – offal, egg yolks and fortified foods such as cereals but these will not provide you enough to stay at optimum levels. A supplement is recommended to help achieve the optimal levels.

How much? Some research has shown consuming 1000iU or 25ug of Vitamin D3 a day over the winter months can help to keep levels where they should be and aid in that much needed protection. If you’re not completely sure though getting a blood test to check your levels is recommended. 

Dry mouth 

Within our saliva there’s an antibody that resides within it called IgA, it’s our first line of defence against airborne bacteria. 

Will it stop you getting ill? Not completely but the potential risk is definitely greater with dry mouth – which is a bigger problem for those of us who run, cycle or exercise outdoors. 

How can we improve this? Adding citrus juice to your water on your cycle or run will help secrete more saliva to help prevent dry mouth from happening. Chewing gum can help too but it’s less practical for a workout.

Low carbohydrate training

Many of us will pick up carbohydrate restricted diets and train to “burn more fat”. This is absolutely not possible. However, performing exercise in a low glycogen mode (stored carbohydrate) will increase the cortisol  (stress) response to that session which in turn will increase suppression on your immune system, potentially weakening your ability to combat infection. 

So, ensure you’re having carbohydrates before your sessions to aid not only performance  but also to protect your immunity. 


It may seem obvious but ensuring you’re supporting your body with the right number of calories plays an integral role in immunity. Calorie deficits both large and short term or small and long term have been shown to increase the risk to getting sick. This is exacerbated when calories in relation to the day’s activity levels and calorie expenditure are dramatically disproportionate e.g that not every day is equal and a two-hour run day should not have the same calorie intake as a 30 minute circuit session. 


It’s well known the protein supports the immune system and has an ability to aid with inflammation through recovery. Having adequate protein to support training, muscle damage and calorie restriction is paramount to maintaining a healthy immune system. 

Zinc Lozenges

While it’s not a full-blown way to protect against risk of infection, sucking zinc lozenges when you start to get the symptoms of a cold or illness is a good plan. Using them over 20-30mins every two hours can help stop the continuation of a cold and possibly prevent it from even happening. Ionic Zinc (iZn) is the active component that supports the immune system and the lozenges need to be sucked to have the desired effect; just taking 3zinc tablets or crunching away at the lozenge will not be as effective. 

Exercise during wetter or colder weather is all about the Risk versus Reward. Make sure you’re fuelling up with the right supplements and food for your workouts and stay healthy right through to spring, which really is just around the corner. 

Eastnine is a fitness app which motivates, supports and guides people working out. 

Consisting of experienced personal trainers, professional athletes and even Olympians, the audio and video app is packed with workouts and programmes to support users in getting fitter, toning up and becoming more confident.