It’s always important to take enough fluids with you when you walk, but how much is enough? Is a simple water bottle enough or do you need an entire flagon?
The answer depends on how intense your walking is. We drink water to replace fluids that we lose during the day. Some of this fluid is lost as urine, some of it is through the skin drying out but some is also lost through sweating.
Sweating helps us control our temperature, keeping us in the biological sweet spot of 37-38 degrees. If our body temperature rises too high your cells start to become stressed and even die, so regulating body temperature is essential to our survival. When you become dehydrated during exercise you lose this ability to regulate your temperature and risk heat exhaustion.
During an intense walk, especially during a hot day, you will sweat a lot to control your temperature. In fact, during the most intense periods of exercise the amount you sweat will rapidly exceed the amount of water your body can biologically absorb.
Isotonic drinks can be helpful to mitigate risk of dehydration. Isotonic drinks contain special substances that help our body increase the uptake of fluids. They also tend to contain small amounts of sugar to help maintain performance during exercise. Please avoid the sugary drinks that are branded to make them look like sports or performance drinks; they are nothing but sugar solutions.
Ultimately during a walk you should aim to drink at least 100ml every 10-15 minutes, especially if you are sweating. You should drink even if you do not feel particularly thirsty as there is no risk to consuming too much water, but too little can have adverse side effects and your performance will suffer, particularly if you are walking against the clock or in an event.
Eating salty-foods can also help tackle dehydration. Salt helps our body to absorb and retain water which will help you replace water lost through sweat. This is mostly important for ultra-long duration walks where you will need to schedule your meals in-between your periods of exercise.
As a side note, our body also needs salt for our nervous system as it is vital to creating the chemical conditions to produce the electrical signals that move our muscles. As a result if we lose too much salt through our sweat we can suffer from cramp. You can alleviate cramp caused by salt loss by drinking salt water or especially salty foods.
You should also learn to recognize the signs of dehydration. Obviously, when we are dehydrated we tend to become thirsty. However, most of us are poor at recognizing our own feelings of thirst. Often thirst is conflated with hunger or even just ignored altogether. Owing to this people often don’t pay attention and can easily become dehydrated due to a lack of mindfulness.
Other symptoms of dehydration include dizziness, light-headedness, headaches, tiredness and dryness in the lips, mouth and eyes. In severe cases dehydration can cause severe lethargy, confusion, a weak or unstable pulse and a dizziness that doesn’t pass when you stand upright.
These symptoms are caused by the brain and the blood being influenced by the lack of water. Our brains are composed of approximately 80% water and will start to condense and shrink when we are dehydrated, causing the symptoms of headaches, nausea, dizziness, tiredness and light-headedness.
Our blood will also lose volume, due to a lower water content, which places more pressure on the heart to compensate. This causes the changes in pulse and can contribute to tiredness as your body struggle to receive the oxygen and nutrients it needs through blood circulation.
In response the blood vessels dilate to try and allow more blood flow into vital areas, which causes swelling and inflammation. This causes an almost twofold attack on the brain – it shrinks due to the lack of water but is also inflamed and swollen due to blood vessel activity.
Walking & Nutrition
For both longer and shorter walks you should consider taking some food with you. For shorter walks a small energy rich sugary snack is recommended. Sugar has been made out to the enemy by the media, but as with most things in our diet, it is beneficial in moderation. Sugar is easily digestible and is one of the best ways for an instant energy kick, which is important for maintaining performance during intense exercise.
Of course the best foods to snack on contain natural sugars, such as dried fruits. Baked goods, candies and other human made sugary treats contain sugars in unhealthy proportions and are nutritionally devoid in other regards (such as their lack of fiber). We often see tennis players eating bananas between games at the side of the court; this is done as stated above to easily digest natural sugar for energy.
Fats slow down the digestion of sugar and can delay the release of energy. Therefore if you want a quick energy boost, avoid fatty foods. One un-expected source of fat can be the margarine and butter people use in sandwiches, which few people often consider.
For longer, slower walks fats can be beneficial due to their higher energy content and slower energy release, making them a better source of sustained energy. Good sources of fats can include healthy oils such as olive oil, although for walking, it is often most practical to stick with nuts and seeds, which are easy to carry and do not require a large amount of space.
However fats are also somewhat harder to digest than carbohydrates, so they should only be eaten in small amounts, especially for more intense periods of exercise.
Instead carbohydrate rich foods should be your primary source of energy. Carbohydrates (a category which includes sugars) are our body’s primary source of energy and are easier to digest than proteins, fats and fiber. This makes them a better choice during exercise when our body has diverted energy away from digestive process and towards the muscles, respiratory and cardiovascular systems.