6 minute read

Water is the main constituent of cells, tissues and organs, and makes up around 60% of our body, reducing as we get older or carry less lean mass. Many of us know that it’s vital for life and we can’t survive for more than a few days without it but, while it’s easy to stay hydrated during the warmer days of summer, it’s as important to pay attention during the colder months.

And, during “cold, ‘flu and Covid season”, staying hydrated is one element in a wellbeing strategy that may be overlooked.

Dehydration has been implicated in a variety of health concerns affecting, for example, physical performance, energy levels, cognitive function, mood management, headache, and gut function (more here), but adequate hydration is critical for immune function too.

The immune system is working away, usually in the background, every minute of every day. Its goal is to keep us safe from an increasingly hostile world, and it has several mechanisms in its defence arsenal.

Our immune system produces several important communication signals and defences, such as white blood cells and secretory IgA (SIgA), that are vital to its effective performance. These products, together with nutrients and fluids, are transported around the body by the blood stream: blood plasma is about 90% water so adequate hydration may help to support blood volume.

Many of us may be familiar with one immune signal, histamine: released from mast cells, histamine is involved in allergic reactions, with symptoms produced including wheezing, itching, rashes, and mucus production. Whilst we often associate it with seasonal rhinitis or hay fever, there’s some evidence suggesting that histamine release may be aggravated by a variety of stressors including low blood sugar or dehydration.

The immune system works closely with the lymphatic system. This system produces a colourless fluid called lymph, made up of around 90% water, that helps to remove abnormal cells and pathogens from the body and transport white blood cells around it. As body water content reduces, lymph production may be affected.

The body has sensitive and precise mechanisms in place to ensure body water and fluid balance are controlled. One of these is to reduce the number of times we go for a wee, conserving water; another is to produce concentrated urine that is darker in colour.

One simple way to monitor your hydration status is by checking how many times you need to pop to the toilet on a daily basis and, when you’re there, noticing the colour of your urine. There’s a handy chart here. When I was training, one of my fellow students was struggling with getting her young daughters to drink enough fluids so she printed out a chart like this and stuck it next to the toilet: that got their attention!

Another mechanism is one we’ve heard about: thirst. Intended to trigger fluid intake, thirst is less noticeable in winter, so our risk of becoming sub-optimally hydrated increases particularly when drinking cool water may become less enticing. This is when we could benefit from a “winter hydration strategy”.

While there’s no lack of information online about hydration and the effects of dehydration, it’s harder to find recommendations for daily intake. Individual requirements are tricky to calculate, varying according to, for example, age, activity and general health. At the moment, the UK’s recommendation is eight large glasses a day for adults, which, with focus and attention, may be easier to achieve than it sounds.

Water is not just the most abundant element in the body; it’s also the most abundant ‘nutrient’ in the diet. Many of us rely on the water in hot drinks, milk, juice or carbonated beverages to hydrate us, yet these may also increase the energy (calorie) provision in the ‘diet’ potentially leading to other health concerns. This may be even more apparent in colder months when we reach for another latte or hot chocolate (maybe with whipped cream and a flake or chocolate sprinkles) to warm us up.

But there’s another source of much-needed fluid: the food we eat. There are many good food sources of fluid, particularly vegetables and fruit. Take a quick peek at this list of certain foods by water percentage; you might be surprised.

So how could you go about creating your “winter hydration strategy”, and making sure you stay fighting fit during the colder months? Try these five simple steps and see if they help:

  • Set a daily goal: this may be the six to eight glasses recommended by the Eat Well guide, or you might prefer to start more gradually, with two or three. What’s important is that you feel it’s manageable: you want to close out each day happy that you achieved your goal and then you can gradually increase the daily intake.
  • Create a reminder or two: set an alarm on your ‘phone. Put a glass next to the sink. When you go to the loo, or stand up from your desk to stretch, or answer the phone, get a glass of water. When waiting for the kettle to boil, get a glass of water. When you have a coffee, be Italian and have a glass of water. Whatever helps you to place hydration at the front of conscious awareness.
  • Invest in a glass, or quality stainless steel, water bottle: I like the Chilly’s range but there are loads of brands available. I have two Chilly’s bottles (so far): a large one that is refreshed every morning and sits in my sightline on my desk, and a smaller one that’s perfect for my handbag or gym bag. It keep water cool and tasting fresh, and it reduces plastic waste and exposure to chemicals in re-useable plastic bottles.
  • Warm up the water: drinking hot water with a squeeze of lemon or a few leaves of fresh mint, or switching out one cup of coffee or standard tea for herbal/fruit tea, are simple ways of making hydration do-able.
  • Choose warm foods with high fluid content: winter warmers such as soup, miso broth dotted with tiny diced vegetables, or warm salads such as roasted tomato, green bean and halloumi can make lovely lunches or simple suppers that taste delicious and add to your fluid intake. Don’t forget warm seasonal fruits too: a compote made of gently poached pear or apple spiced up with cinnamon or nutmeg makes a great addition to natural yoghurt.

Of course, you may have your own simple steps that are tried, tested and trusted, in which case, well done. Please share them, and tell me: how often do you consistently follow them?

If you’ve got questions about anything in this piece or if you’d like a (free) chat about your hydration concerns, contact me: I may be able to help (and if I can’t, I’ll probably know someone who will!).