Just add water

“Dehydration leads to a reduction in physical and mental performance, your heartrate will increase a bit faster, you’ll get hotter quicker and exercise will just feel mentally tougher,”

Class is in session and first off, we’re going to learn why water is good for you in the first place. As Manning explains, we can’t intrinsically produce water to satisfy our need for it and it’s needed for all sorts of body functions.

“Most of our biochemical reactions actually occur in water and it helps provide structure to all sorts of components of the body. It’s needed for digesting, transporting and absorbing nutrition,” the dietitian says.

Temperature check

When it comes to exercise, there are  a few reasons water becomes important, one of which is keeping your temperature in check.

“The means of your body keeping cool during exercise is through sweating. Every hot bead of sweat from your skin helps carry heat out of the body and water keeps our temperature in that narrow range. The only downside of that is we lose fluid as a result,” the personal trainer explains.

So essentially, if you’re working out in a warm or humid environment or you’re doing a super intense workout, you’ll lose more fluid because your rate of sweating will increase. And if you sweat too much without replenishing, Manning advises you’re then risking dehydration.


Hydrating before, during and after your workout

Everyone’s workouts are different and so are your hydration needs.

“Some individuals will start sweating earlier or later, less or more, and will have differing sweat compositions and what makes it even trickier is that many of these factors are not set in stone,” Manning explains. 

Still, he says there is one common goal which is to “match your fluid intake with your fluid loss.” 

To calculate this, the personal trainer suggests roughly estimating the amount of fluid you’re losing by comparing your weight pre and post training session. He reckons this will give you some great insights for longer sessions and give you a general target of how much water you should have had by which point in time. 

In general, the personal trainer and dietitian suggests that after your workout “we generally want to replace 125-150 percent of fluid within two to six hours.” 

For example, if somebody weighs 50kg and you lose 1L of fluid, you’d probably aim to drink around 1.25-1.5L over a period of time. 

Of course, if you want specifics, Manning recommends you check in with an accredited sports dietitian.

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Dehydration vs overhydration

Boy it sucks when you forget your water bottle when you start working out, right? And look, it might not seem like a big deal but as Manning warns, being dehydrated can hamper the efficiency of your workout.

“Dehydration leads to a reduction in physical and mental performance, your heartrate will increase a bit faster, you’ll get hotter quicker and exercise will just feel mentally tougher,” he says.

A 2018 study by the Georgia Institute of Technology backs Manning up because researchers found that athletes who lost fluid equal to 2 percent their weight took a hit to their cognition.

If you’re looking to do explosive movements like a clean and press, having a brain fog caused by dehydration isn’t ideal. Additionally, the dietitian advises in severe cases individuals can experience nausea, vomiting and other gut problems. So, it’s definitely better to start your exercises hydrated.

On the other hand, it’s also easy to think you need lots of fluid and “guzzle down a lot more than you need in one go, leading to varying degrees of gut discomfort,” Manning explains.

He adds that our kidneys are superstars here by regulating our fluid balance pretty tightly. If you do overhydrate “the antidiuretic hormone that usually holds onto water becomes downregulated which leads to us going to the toilet more frequently and for longer.” 

To turn this situation around, Manning recommends sitting down and stopping your exercise and allowing this to take place until you feel good as gold again.


Can water help you build muscle?


Not exactly, but it can help your muscles look plump. According to Manning, “Water isn’t likely to help you build protein and muscle fibre, but water is certainly found inside muscle which can improve its appearance.” 

You can still think of hydration as your nutritional hype girl. The dietitian explains that if your goal is to gain muscle, water can help digestion and therefore aid in the uptake of nutrition.


Does water help me lose weight?

High fives all round because Manning says drinking water certainly supports your weight loss goals. “Water consumed through fluid or what is already found in food contributes to how satisfied and full we feel after a meal and in this way, it can help assist in keeping our portions modest and in avoiding overeating,” advises the dietitian.  

And if you’re feeling those snack cravings coming along, Manning suggests having some water first before reaching for grub because “sometimes thirst and cravings can be confused.”


Byron Manning is a personal trainer at Aquanation with a Bachelor of Food and Nutrition Science at and Masters of Dietetics at Deakin University. Learn more.