Drinks and hydration is currently very topical, what with all the hot weather we’ve been having! Even when we haven’t been experiencing record breaking temperatures, being adequately hydrated is still important. Water is essential for life.
Hydration is essential
Our bodies are made up of ~60-70% water (as adults), but decreases as we age. It has numerous roles in the body including body temperature regulation, maintaining blood volume, protecting tissues and joints and removing waste through urination.
Getting the right balance is key!
Getting the right balance is key, i.e. under-hydration or over-hydration can cause dramas (Hew-Butler et al., 2017)…
DEHYDRATION can compromise mental and physical performance, including aerobic, anaerobic, strength and endurance performance (McCartney et al., 2017).
Dehydration increases your core temperature and heart rate and increases your perception of exertion; making you feel like you’re working harder (Thomas et al., 2016). Not good.
OVER-HYDRATION can cause bloating, discomfort and reduce performance, but in extreme cases can also be FATAL (Nolte et al., 2015).
So how can we keep ourselves hydrated?
Foods for fluids!
Approximately 20-30% of our total fluid intake comes from foods (BNF, 2016; Guelinckx et al., 2016)! This includes fruit and veg (another reason to eat your 5-A-Day!), soups, stews, casseroles, smoothies (but be mindful that fruit juices, vegetable juices and smoothies contain “free sugars”).
Fluids from drinks provides the remainder of our total fluid intake, and includes water, sugar-free drinks, low fat milk, tea and coffee (PHE, 2016).
The UK’s Eatwell Guide states to limit fruit juice and/or smoothies to 150mL per day (- this will be due to the free sugars, and the consequences of the extra calories and impact to your dental health).
Do caffeinated drinks count?
Yes. It is often thought that caffeinated drinks don’t count towards your fluid intake and dehydrate you because of the diuretic effect (- i.e. they make you pee more).
However, research suggests that the diuretic effects of caffeine is overstated on regular drinkers, especially if <180mg (Thomas et al., 2016). To give you an idea of what 180mg of caffeine is like…
- A brewed mug of coffee has ~95-165mg caffeine
- A brewed mug of tea has ~25-48mg (Mayo Clinic, 2017)
Therefore caffeinated drinks are fine, and actually tea/coffee may be a good way for elderly people to get the fluids in if they don’t like other drinks. However, alcohol is a diuretic that can dehydrate you (Drinkaware, 2016) (and delay exercise recovery).
What types of fluids are best?
Ever heard of HYPERTONIC, ISOTONIC and HYPOTONIC? Basically these fluids have more, similar or less sugar and salt than the body, and are absorbed at different rates.
- Hypertonic drinks (e.g. cola, pure fruit juice) empty more slowly from the stomach than water, and are useful for replenishing energy stores. As these contain more carbohydrate, they can worsen dehydration, plus may cause digestive distress. It is best to have these drinks alongside isotonic drinks to help rehydrate after exercising
- Isotonic drinks – a typical sports drink, is absorbed as fast as, or faster than plain water
- Hypotonic drinks – a typical “lite” sports drink or very dilute squash, absorbs faster than water
In general, water is appropriate when exercising less than an hour at low to moderate intensity, and choose isotonic drinks when exercising for longer than an hour at moderate to heavy intensity (IOC, 2016). Fluid choice does depend on exercise intensity, duration and your goals (and taste!).
What if we don’t drink enough fluids?
We become dehydrated. Having enough fluid intake is essential for short-term and long-term health. Dehydration causes thirst, dry mouth, tiredness, dizziness, headaches, poor concentration, constipation, kidney stones and urinary tract infections. It can also make constipation worse.
Dehydration should not be used as a means to “make weight” for a weight division sport, such as combat sports, rowing and weightlifting. This is a dangerous practice that has been fatal, such as the MMA fighter in 2015 – but unfortunately there are many cases of this happening in combat sports.
Is it possible to DRINK TOO MUCH FLUIDS?
YES! We’re always told to “drink plenty of water”, but what does this actually mean – how much is plenty?!! Also, it’s not wise to drink so much that you overload yourself!
There is a condition known as HYPONATRAEMIA (meaning low blood sodium), which can be fatal if untreated.
Exercise-associated hyponatraemia (EAH) can occur when someone drinks too much hypotonic fluids, during/after exercise, and basically excessively dilutes their blood.
This is quite a rare condition, however we do need to raise awareness and education around safe hydration practices to prevent this.
😔 Soldiers, athletes and charity marathon runners, among others have all died due to hyponatraemia (Gierer, 2016; Hew-Butler et al., 2017).
Some risk factors for developing EAD:
- Excessive drinking behaviour
- Weight gain during exercise
- Low body weight
- Slow pace/low intensity exercise
- Non-steroidal anti-inflammatory drugs (NSAIDs) (e.g. Ibuprofen, Naproxen, Diclofenac or high dose Aspirin)
- Prolonged exercise
- Cold environmental temperatures (Burke & Deakin, 2013; Hew-Butler et al., 2017; Makhni et al., 2017)
How much fluids do we need?
In the UK it is recommended that the general population has 6-8 glasses (~1.5-2L) daily. This is GENERAL advice only though – Not tailored to you as an individual. Fluid requirements are different for everyone and an individual’s requirements can change too, depending on internal and external factors.
Internal Factors include…
- Your age
- Your current level of hydration
- How much you typically sweat
- Activity levels
- If you have any medical conditions such as kidney disease, chronic liver disease, Syndrome of Inappropriate Antidiuretic Hormone (SIADH for short!!)
- If you’re suffering with a fever, vomiting
- The amount and type of fluids you’re consuming and if it’s consumed with any food
External Factors include…
- The weather – temperature and humidity
- How acclimatised you are
- The altitude
- Your clothing and any equipment you’re wearing
You need more fluids when:
- In hot and/or humid environment
- Physically active
- Experiencing diarrhoea or vomiting
- Running a fever
- Sweating a lot
An easy and practical way to assess if we are drinking enough is to check our pee – for frequency, volume and colour (see chart below).
“Specified Drinking Plan” or “Drink to Thirst”?
Typically, there’s two schools of thought for hydration strategies for athletes:
- A specified drinking plan and
- Drinking to thirst (Kenefick, 2018)
But both aim to prevent negative effects of under- or over-hydration and preserve performance and wellbeing.
There’s pros and cons to both. And in both cases it’s important to avoid drinking so much that you end up gaining weight by the end of the session (Kenefick, 2018)!
You can weigh yourself before and immediately after exercise to help gauge an estimate of sweat loss (IOC, 2016) – if you have gained weight, then you’ve drunk too much!
It’s difficult to recommend a specific drinking strategy – this needs to be done on an individual basis that accounts for factors such as individual needs, the specifics of the event/sport, environmental conditions and recovery times.
YOU MAY ALSO LIKE TO READ THIS ON YOUR SWEAT RATE:
9 Ideas to Keep You Hydrated & on Top Form!
- Monitor urine colour as a gauge of hydration status
- Carry a water bottle around with you for easy access and help you monitor how much you have drunk
- If you know you always forget to drink, set yourself an alarm or leave yourself Post–It notes to remind you
- Don’t forget that foods (e.g. fruit and veg) can contribute towards fluid intake
- Avoid starting a training session or competition dehydrated
- Weigh yourself before and after an exercise session:
- Avoid weight losses >2% and
- Avoid weight gain from before to after exercise
- If you’ve lost weight after exercising, this will be fluid losses from sweating, so replace these 125-150%
- Unless you’re doing prolonged heavy exercise, water will be fine
- Never trial a new drinking strategy in a key event/competition
- Avoid alcohol after exercise as this can dehydrate you and delay recovery
For more information and tailored advice, please get in touch.
It is crucial to get your food and fluid intake right if you want to control your IBS symptoms and if you want train harder, go faster and recover quicker from training sessions and competitions. Dietary requirements are highly individualised and there’s no ‘one size fits all’ approach. Working with a Registered Clinical & Sports Dietitian to develop a bespoke plan based on your unique requirements will help to ensure the most appropriate strategy and best results are achieved. I’m here for you, so please feel free to get in touch.
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BNF. (2016). Healthy hydration guide. Available from www.nutrition.org.uk/healthyliving/hydration/healthy-hydration-guide.html
Drinkaware. (2016). Available from: www.drinkaware.co.uk/alcohol-facts/health-effects-of-alcohol/effects-on-the-body/alcohol-poisoning/
Gierer. (2016). Soldier dies after falling ill on first day of Ranger school. Ledger-Enquirer. Available from: http://www.ledger-enquirer.com/news/local/military/article92206607.html
Guelinckx et al. (2016). Contribution of Water from Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys. Nutrients, 8(10), 630.
Hew-Butler et al. (2017). Exercise-associated hyponatraemia: 2017 update. Frontiers in Medicine.
Kenefick. (2018). Drinking strategies: Planned drinking versus drinking to thirst. Sports Medicine, 48(Suppl 1), 31–37.
Makhni, et al. (2017). Exercise-Associated Hyponatraemia (EAH). In Orthopaedic Emergencies. Springer, Cham.
Mayo Clinic. (2017). Caffeine content for coffee, tea, soda & more.
McCartney et al. (2017). The effect of fluid intake following dehydration on subsequent athletic and cognitive performance: A systematic review and meta-analysis. Sports Medicine, 3(1), 13.
Nolte et al. (2015). Exercise-associated hyponatraemic encephalopathy and exertional heatstroke in a soldier: High rates of fluid intake during exercise caused rather than prevented a fatal outcome. The Physician & Sportsmedicine, 43(1), 93–8.
Thomas et al. (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise, 48(3), 543-568.
(Some images from unsplash.com)