There’s far more to getting hydration right that simply being told to “take a few sips of water every 15 minutes”. Equally important, be exceptionally wary of claims made by companies whose business relies on selling you supplements. With that out of the way, let’s examine the science.
What is dehydration?
The NHS tells us that dehydration happens when your body loses more fluids that what you take in. It goes on to warn that – left untreated – it can become a serious issue. The NHS also warns that children, and older people, are more at risk from dehydration.
So far, that’s easy enough. What many people don’t grasp is that our bodies are all unique. Some people can, under the same conditions, get dehydrated easier than others, even when they’re the same age. It is therefore vital that you learn to recognise the symptoms for your own unique needs.
Symptoms of dehydration
As with most bad things, prevention is better than cure. However, if you were slow to act, and start experiencing these symptoms, you should act immediately to alleviate it.
- Feeling thirsty, especially of that’s a constant
- Your urine is dark in colour, and smells strong
- General fatigue (more on this later on)
- Not weeing as regularly as you usually do
- Spells of dizziness
- When you stop sweating, even though it’s a hot day – this is a serious warning sign
- Dry mouth, lips, tongue and throat
- Possible muscle cramps
- Headaches
Pay particular attention to these symptoms, as we’ll be comparing them to symptoms of over hydration later on.
Risk factors for dehydration
Anyone can become dehydrated, but some people are at increased risk. Older adults’ bodies naturally store less fluid, meaning your risk of dehydration increases as you get older. People with chronic illnesses, including diabetes, are at increased risk, too. Even having a cold of the flu increases your risk of dehydration.
Some risk factors are self-inflicted, such as being severely hung-over. Also, coffee (amongst other things) is a diuretic, and diuretics make you wee more than usual. That simply means drinking lots of coffee can increase your risk of dehydration.
However, the single biggest risk factor you’re likely to encounter is the weather. On hot days, through sweat you can lose well over a litre per hour. That’s fluid you need to replace.
Symptoms of over-hydration
Dehydration is bad, but so is over-hydration. That’s also known as water toxicity, or water poisoning. Over-hydration can lead to a dangerous electrolyte imbalance, and though rare, there are cases when it caused people to die.
It is therefore vital that you recognise the symptoms, and act early on. These include:
- Nausea or/or vomiting
- Headaches, caused by pressure on the brain
- Drowsiness
- Possible muscle cramps
- Changes in mental state, such as confusion, or disorientation.
Can you spot the overlap with dehydration symptoms? That’s a real problem.
Risk factors of over-hydration
Most at risk are people who are physically active outdoors. Yes, like cyclists. However, the condition is strongly linked to people with kidney or liver disease. It can also affect people at risk of heart failure.
Finding the balance
The kidneys in healthy adults can eliminate around one litre of water per hour. Kidneys of older people tend to be less efficient, and therefore can deal with less water. Under normal circumstances, you should not consume more liquid that what your kidneys can handle.
However, earlier on, we saw that adults can lose over a litre of water per hour. So, how do we balance that against our kidneys’ limit of one litre of water per hour, maximum? When cycling in the UK, it is exceedingly unlikely that you’ll hit the climatic conditions where you would lose over a litre of water per hour.
As a very rough guide, you should try to not exceed the one litre per hour fluid intake. If (like me) you’re getting on a bit, you should reduce that limit further. Handily, cycling water bottles tend to come in 500 ml sizes, making measuring your fluid intake easy. If you drink two of those per hour, you’re getting into risky territory.
Equally, the “have a few sips every 15 minutes” advice could result in you not drinking remotely near enough. On warm to hot days, personally I’d be drinking two water bottles per hour. Pay attention to how much you need to wee, and how much you’re sweating, too. Remember, if you fairly suddenly stop sweating, it’s time to stop, get off the bike, find shade, and drink water. After all, heat stroke is NOT fun, so ensure you read that linked post, and know the symptoms!
The effects of dehydration
Aside from the symptoms mentioned above, being even mildly dehydrated will reduce your athletic performance. Hills will seem steeper, and you will suffer more. Why do that to yourself?
Electrolytes, additives and supplements
Let’s be very clear here: I am not a doctor. I am also not in any way medically qualified. As a result, I will offer no advice at all about replacing lost electrolytes, adding salt (or anything else) to your water.
I will however give you some very clear advice: with anything that impacts on your health, speak to your GP, and take what they tell you over any Internet article.
I started this post by telling you that your body is unique. What works for someone else may, or may not work for you, and you need to find answers that work for your body. With that, you should certainly ask your GP for advice.