How to boost your immune system during winter

There’s nothing worse than a winter bug to derail your triathlon training. Luckily, Renee McGregor has the nutritional tips to keep you fighting fit and healthy…


When the days are short and your next race seems like a lifetime away, even the most disciplined of us can struggle with motivation to get out and train. Add to this a slight niggle or sniffle and this can be the deal breaker when it comes to consistent training. So what tips can you take on board to help you prevent those winter bugs and blues?


First off, sign up to a race as this will definitely help you stick to some form of training plan. Once you’ve established this then you can start to focus on how to keep your body working like a well-oiled machine.

The winter months are usually a time when nutrition and the focus on looking after yourself take a back seat. As the temperature drops, your resolve to eat more fruit and salad can weaken, with a tendency to favour more comfort foods. And as the party season beckons, we may find ourselves feeling a little run down and even less inclined to train. But there are several steps you can take to help boost your immune system.

Make sure you eat nutritious meals during winter

winter is the time to load up on nutrients. Before you roll your eyes, this doesn’t mean slaving away for hours over a hot stove. A few years ago I invested in a slow cooker and it made such a huge difference to my life. By putting aside as little as 10-15mins either the night before or in the evening, you can prepare all the ingredients you’re going to throw into the slow cooker. Use a variety of seasonal vegetables – see middle panel for more information and other fuelling suggestions for the off-season – to make soups, casseroles and even curries. Knowing that there’s a delicious and nutritious meal ready and waiting for you post-training can be all the motivation you need to squeeze a session in after work.

Supplement with Vitamin D

Trying to absorb sufficient sunlight to produce Vitamin D is a challenge even during the summer in the UK, and pretty much impossible during winter. Vitamin D is the go-to nutrient to help protect your immune function and boost your mood. There are very few foods that naturally provide you with sufficient Vitamin D, so this is a supplement I’d really recommend through the winter months. How much you supplement with will depend on your blood levels so it may be worth asking your GP for a blood test to check. Individuals ho are highly active benefit from their vitamin D levels being above 75.

Should I take probiotics?

In the lead-up to Rio, I recommended that all the athletes I worked with take a 12-week course of probiotics. This is because it’s been proven that probiotics prevent upper respiratory tract infections in athletes. And as this is the time of year when coughs and cold bugs are abundant, it’s worth considering introducing a probiotic to help boost your immune system. While I’m not a huge advocate of supplements, I do suggest taking a probiotic supplement (and vitamin D) rather than the probiotic drinks.

Comfort carbohydrates

We all know that feeling, the temperature plummets and all we want to do is eat stodge. But if you’re clever with your choices and stock up on nutrient-dense carbohydrates, then don’t be afraid to eat them. Carbohydrates are important to help your muscles work efficiently, especially on those high-intensity training days. Aim for a third of a plate at every meal of wholegrain, nutrient-dense carbs such as sweet potato, pasta, rice, to name a few, on training days and a quarter plate on non-training days.

Stay hydrated

While over the summer months it can be easy to keep on top of your hydration, when the temperatures plummet reaching for a cold drink is the last thing on your mind. But being hydrated encourages saliva production, and saliva is your first line of defence against infection. One tip is to flavour your fluid – use no-added sugar squashes or fruit/herbal teas to encourage you to drink.

Get enough sleep

Several studies have clearly demonstrated that a minimum of seven hours’ sleep – but ideally eight – a night is necessary to help repair the body both physically and psychologically. Few people know that growth hormone, responsible for physical repair, is at its highest around 12-2am. So aiming to get to bed early enough will ensure that you make the most of this window, especially as levels start to decline the older we get.

Also, try and get into good sleep hygiene practices, such as putting your phone or laptop away at least 30mins before you go to bed and instead doing some reading or even restorative yoga. Do this, and the above, and you’ll reap the energy rewards through the winter months and into the new season.

Winter fuelling for triathlon

Stay healthy this off-season with these hearty food suggestions

Fruit and veg

Try casseroling, making soups or curries with seasonal veg. Autumn also brings an abundance of apples and blackberries – try stewing and use as a topping on porridge or a slightly more indulgent dessert with Greek yoghurt or custard.

Oily fish 

Aim for 1-2 servings as week. Oily fish is a great source of omega-3 fatty acids, which help alleviate fatigue and inflammation. Plus, they’re high in calcium, giving your bone health a boost.


Aim for four servings a day to ensure you continue to promote good bone health and also maintain lean muscle mass.

Beans and pulses


These make a great addition to stews and casseroles. They’re high in soluble fibre and help to keep you fuller for longer.