Fluids: how much do you really need?

The Importance of hydration

Regardless of whether your goal is in building muscle, losing fat or improving sports performance, remaining suitably hydrated should feature at the very top of your priorities. Here at Cardiff Sports Nutrition we explore exactly why you need to remain hydrated, what the consequences are if you don’t, and what the optimal fluid strategies should look like.

What does fluid intake do for us?

It may seem strange to be asking such a basic question when we take drinking liquids for granted – but it’s worth understanding why in the context of your fitness goals.

Fluid intake helps to regulate your body temperature and transports nutrients through the body. This is vital for processes such as shuttling vitamins and minerals to muscles, digesting food and disposing of waste products. There is also a significantly greater need for fluids when you factor training into the equation.

Fluid intake helps to regulate your body temperature and transports nutrients through the body

How does exercise alter fluid intake?

Exercise affects fluid levels in three main ways, which you may already be aware of:

  • Training intensity
  • Training duration
  • Training environment

These all need to be considered when judging how much fluid is needed. It goes without saying that a football or rugby match calls on a greater amount of fluid than a quick 30-minute arm pump. Warm weather training (such as summer circuits and boot camps) will also result in a larger amount of sweat produced.

Fluid intake also helps to up-regulate electrolyte levels. Electrolytes are vital for muscular contraction, so it’s important you keep your levels topped up. The longer and more intense a training session is, the more your body’s electrolytes become depleted. A great deal of sodium is lost through sweat for instance.

So how much fluid do we need?

  • Non-training days: you’ll need roughly 1ml of fluid per calorie burned. If you’re burning 2500 calories a day, that’s 2.5 litres. Relatively simple stuff. This figure of course increases in hot climates.
  • Training days: the American College of Sports Medicine (ACSM) suggest 5-7ml of fluid per kg of body weight at least four hours prior to exercise. If you weigh 70kg, that’s anything from 350ml to 490/500ml – roughly one small bottle.

You can also try weighing yourself before and after training (or match for those budding athletes among us). Every kg lost roughly equates to 1 lost litre of water. You should aim to replace lost water by 150% post-workout/post-match. For example, losing 1kg over the course of your session or game would need to be replenished by 1.5 litres of fluid. 0.5kg lighter = 750ml.

You should only consider isotonic drinks if your activity lasts over an hour. Footballers, rugby players and endurance athletes for example would all benefit

Are isotonic sports drinks worth taking?

You should only consider isotonic drinks if your activity lasts over an hour. Footballers, rugby players and endurance athletes for example would all benefit. Isotonic drinks are typically calorie-dense. Consuming a high-carb, high-sugar product during a 30-45 minute session may result in you consuming more calories than burned off. If you’re looking to lose weight, this is of course, a bad move. Want to create your own energy drink? Take a look at Vitargo's range.

Bodybuilders or fitness fanatics training for less than an hour would be far better off sticking to water or an amino acid complex. Read about Branched Chain Amino Acids - what they are and what they do here.

What happens when we’re dehydrated?

Don’t think you can get away without water. Losing fluid without replacing it causes your heart rate to rise and depletes your volume of circulating blood. This extra strain on your heart and internal organs makes exercise harder and negatively affects training performance.

If you’re looking to pack on some serious size, how can you expect to put your muscle fibres through enough stress and resistance if you’re not sufficiently hydrated? On the other side of the coin, if you’re trying to shed the pounds, how can you expect to lose fat if you’re not providing your body with the fluids needed to fuel intense exercise?

What about those who cut water for a photo shoot or competition – won’t that make me look and feel good?

Due to the reasons listed above, you shouldn’t entertain this idea unless you are a genuinely competitive bodybuilder or professional fitness model. If you want to drop water weight in a relatively short space of time, manipulate your food instead. In the short term, low-carb diets can induce a leaner look due to a loss of water weight. [Side note: low-carb diets are less effective for weight loss in the long-term, but that’s for another day]

As always, Team CSN are here to help, call or email us today and we can give you professional, unbiased advice on all your nutrition and supplement needs.