Estimating Your Hydration Needs

We’ve all seen athletes walking around with gallon-sized water bottles, electrolyte tablets and sports drinks al to ensure they are "staying hydrated." And while you know drinking water is important, you may be wondering if the guidelines are really all that different for an active individual and someone who's more sedentary.

The short answer is "Yes," but there’s no "one size fits all" for how much water each athlete should drink. That's why it's so important to be aware of your training activities and to gain an understanding of your own needs. Below are some guidelines help outline the measures an athlete should take to stay hydrated based on personal activity level and needs. Understand, however that there are no "rules" and needs can vary from day-to-day and person-to-person. Here is what you need to know about hydration for athletes including when to hydrate and how to calculate hydration.

Effects of Dehydration on Athletic Performance

For most of us, we do athletics because we like doing well at stuff – PBs, winning, cups and medals are very nice! Not having enough fluid to make you body function correctly can get in the way of this – in the long term, not just on the day itself!

Decreased Endurance - it can lead to a decrease in blood volume, which in turn reduces the oxygen and nutrient delivery to working muscles.

Impaired Cognitive Function - Mild to moderate dehydration can impare yrou ability to think straight, including attention, reaction time, and decision-making skills needed to compete on the day.

Slower Recovery Times - Adequate hydration is crucial for proper recovery after exercise. Dehydration can slow down the removal of waste products from the muscles, prolonging the recovery process and potentially increasing the risk of delayed onset muscle soreness (DOMS).

Increased Risk of Injury - Dehydration can cause muscle cramps, which can increase the risk of strains and other injuries. Additionally, a decrease in joint lubrication due to fluid loss can lead to joint stiffness, pain, and an increased likelihood of injury during physical activity.

Hydration Guidelines for Athletes

Here's the thing - we are humans and we are all different. While the human body is made up of almost 60% water, an individual's water content varies based on factors like age, sex, and body composition.

Every individual has a different sweat rate which leads to different levels of fluid loss during activity. Of course, work harder in a warmer place (or more humid of course) and this will lead to a different level of fluid loss. Someone lifting weights for 1 hour in an air-conditioned gym isn't likely to lose nearly as much water and electrolyte content as someone running a marathon in the tropics.

It is possible to break this down into three main categories: pre-hydration (consuming fluids before exercise); hydratione during exercise; and rehydration post-exercise. Paying attention to all three categories will reducing the likelihood of experiencing dehydration during or following an athletic event - if you still don’t see the problem go and reread the bullet points above!

Pre-Hydration

Being hydrated isn’t a matter of a quick drink before starting and activity. To ensure you start well-hydrated, aim to consume 500-600 ml of water 2-3 hours before activity and an additional 250-350 ml of fluid 30 minutes before starting. This is in addition to your normal intake and is aimed at ensuring there are sufficient fluid to make your body function correctly.

Hydration During Exercise

During physical activity, aim to drink 150-200 ml of fluid every 10-15 minutes to replace sweat loss. Obviously, if it is particularly hot, or you are working very hard – for example, for a prolonged session of HIIT training, forcing you heart rate to stay high and sweat more consume 200-300 ml every 10-15 minutes during the workout.

Post-Exercise Rehydration

After exercise, it's essential to rehydrate by consuming fluids equivalent to 150% of the weight loss experienced during the activity – this is a general measure of the sweat loss but not everyone is going to go to those lengths. As a general rule, have as much as you consumed before and during the exercise over the following 2 – 3 hours.

The other aspect of rehydration to consider is electrolytes. Electrolytes, such as sodium, potassium, and magnesium, are vital minerals that help to maintain fluid balance, muscle function, and nerve signalling. These are lost through excessive sweating in prolonged exercise. For most of us, these minerals are obtained through a balanced diet and there is no need to supplement them, unless the intensity and duration of training is above an hour or so.

Sports Drinks vs. Water

For the majority of athletes, water is the correct choice for maintaining proper hydration. For low to moderate-intensity exercise lasting less than an hour, this is pretty much every athlete. For longer duration and/or high-intensity activities, however sports drinks containing electrolytes can be beneficial in replenishing fluid efficiently BUT be careful to avoid ones laced with vast quantities of sugar and other substances like caffeine. Especially be aware of any offering miraculous ingredients that will give some wonderful boost – and check them against the WADA banned list!

Signs of Dehydration and Overhydration

Monitor your body for signs of dehydration, such as thirst, dry mouth, dark yellow urine, fatigue, dizziness, headache, and muscle cramps.

Over hydration can also be bad. Yes, it is possible to drink too much water, and this can lead to a condition called hyponatremia (low blood sodium levels). This is where the electrolytes discussed earlier come in. To avoid this, aim to drink fluids containing electrolytes during prolonged or high-intensity work.