Eat Well, Feel Well: The Importance Of Hydration

The Importance Of Hydration – Gary Sweeney, IRFU National Talent Development Pathway Performance Nutritionist

Is fluid intake and maintaining an optimal hydration status every day important? The simple answer is yes, but why?

Water, an essential fluid for life, makes up approximately 60% of your body mass, and maintaining a euhydrated state (normal level of hydration), meaning you have consumed a sufficient amount of fluid to maintain normal water balance, is important for many bodily processes such as speed of thought, digestion of food and brain and muscle function to mention a few.

Even a moderate loss of water from the bosy (referred to as dehydrating) and not keeping ‘topped up’ may result in common symptoms such as dry mouth/tongue, thirst, headaches, lethargy, fatigue, dry skin, muscle weakness, light-headedness, dizziness and a lack of focus.

Even a 2% loss of body weight used as a measure of fluids lost during exercise has been shown to negatively impact sports performance, thus having a personal plan and drinking a sufficient amount of fluid could be the difference between winning and losing.

Why do we lose fluid?

Dehydration is the process of water loss from the body, and being in a dehydrated state means you no longer have sufficient fluid in your body to optimally function. Naturally, even at rest we lose fluid by as much as 1-3L per day.

Each day we lose fluid naturally by breathing (respiratory loss), urinary and fecal loss (going to the toilet) and increased fluid loss from naturally sweating, with increased sweat rates occurring during exercise. Factors effecting how much you lose can include individual body weight, individual sweat rates, environmental temperature, physical activity, diarrhea or having a fever.

How much do we need to consume?

Rehydration is the process of gaining and replacing lost water back into the body. Although there is no exact answer for how much water you should consume as everyone may have different needs depending on individual and environmental factors, aim for approximately 35ml of fluid per kg body weight. That’s just over 2 litres for a 60kg adult, or 2.8 litres for a 80kg adult. Active children should aim for 1-1.5 litres per day (approx. 4-6 glasses) and everyone should consume extra fluid if exercising.

Do I need to consume only water?

Fluid intake doesn’t always have to be from plain water. Although plain water is your best fluid for rehydration, it can also be found to constitute approximately 87% of milk and over 90% of some fruit and veg such as melons, berries, cucumber and tomatoes, all of which can contribute to your overall daily fluid intake.

How do I know if I’m hydrated or dehydrated?

Simple markers of hydration status stim from the W.U.T approach.

• W: Weight
• U: Urine colour
• T: Thirst.

Thirst alone is a poor indicator, and usually once experienced you are likely already dehydrated. Combine two of these markers together to monitor your hydration status. Thirst and checking your urine colour output daily are two easy markers to use. Measuring body weight can also be used, although it’s slightly trickier for accuracy of hydration status as many variables effect weight.

However, athletes would sometimes measure their weight pre and post exercise to determine how much weight is lost during exercise, and for each kg lost, they would rehydrate with 1 ½ litres of fluid by using milk, water or smoothies, which are all popular rehydration fluids.

The most prudent approach especially for athletes is to have a plan, on how much to drink and when, however in most settings drinking to thirst and monitoring urine colour will be the plan.

A dark urine colour would suggest you may need to drink more, while a light straw colour would suggest you are spot on with you fluid intake. Use this chart to help guide you. Aim for 1-3 in colour.

So to stay hydrated, here are a couple of tips:

• Start off your day with a glass of water – a habit you can form easily by placing a water bottle at your bedside locker.
• Aim for 35ml of fluid for each kg body weight – eg 60kg should drink 2.1L fluid a day.
• Carry a water bottle with you on the go,
• Don’t forget you can use milk, fruit smoothies and fruit and vegetables to help keep you topped up as well as plain water.
• Try adding some slices of fruit into your water to improve taste.
• Sip small amounts often throughout the day, and if you exercise consume a bit more.
• Consume 1 ½ Litres of fluid for every 1kg lost during exercise.
• Remember, monitor urine colour daily, sip fluids often and stay hydrated.

You can read the first part of our Eat Well, Feel Well series with Emma Tester, Lead Performance Nutritionist Munster Rugby here, while Daniel Davey, Senior Performance Nutritionist with Leinster Rugby, explored the topic of nutrition fundamentals here. Last week, our series continued with Marcus Shortall, Performance Nutritionist with the Ireland Sevens programme, discussing the different energy sources.

For more on the IRFU’s Eat2Compete series for younger athletes, click here.