Precision Hydration

Weight management and hydration guidelines for Taekwondo

At Precision Hydration we work with a long list of pro and elite athletes and organisations in the Premier League, NFL, NBA, Formula One, International Rugby and across the combat sports to personalise their hydration strategies so they can perform at their best for longer.

We’ve worked with a number of athletes in MMA, as well as other weight-category sports such as rowing and so issues around weight management is something that comes up regularly for us. Many of your athletes will be tempted by the allure of weight management strategies, but what guidance should you as an instructor be giving them so they can engage in safe hydration practices? 

Are your athletes competing in the right weight category?

Before considering an athlete for competition in a lower weight category, two key questions must be considered…

1) Is dropping to a lower weight category necessary for the success of the athlete?

However beneficial it may be for an athlete to fight in a lower weight class – if this is going to require regular and extreme drops in weight from a healthy level then the athlete should fight in the category they comfortably fit into. What an athlete may gain in fighting lighter opponents can be cancelled out by potentially fighting dehydrated, malnourished, having lost functional muscle mass and in a poor mental state during/leading up to the fight.

You want your athletes to have their total focus on their training and recovery, encourage an athlete to drop too much weight and their mind will primarily be on where their next feed is coming from (basic psychological needs models show that humans cannot extend their focus beyond basic physiological needs – e.g. food, water, warmth etc – if these are not satisfied.

2) Is dropping weight going to harm the athlete’s general health?

Deliberate weight reduction of any kind is not a healthy practice, it should be done as infrequently as possible during a season and the athlete should be on weight for as short a time as possible if they’re fighting at lower weight than their natural level. Dehydration and lack of appropriate food for physical activity can have serious health repercussions, such as low blood pressure and irregular heart rhythms.

If you decide that an athlete can safely compete at a lower weight then the next step is to support them in making weight through safe weight management practice. The following guidelines will allow your athletes to lose and manage their weight in a healthy manner leading up to a fight, whilst losing minimal useful training adaptations.

Long-term weight management strategies

Despite it being reasonably easy and acceptable to lose between 1-2 kg overnight before a weigh in, the majority of weight loss should be done over a sustained period of time.

Before suggesting the following steps, it’s important to assess the athlete’s current diet and see where energy input can be reduced and to look at the athlete’s training program to see where energy output can be increased.

Reduce/replace carbohydrate intake

One that can help an athlete drop weight is a reduction in the carbohydrate portion of main meals. This should only marginally cut down the total energy intake of the meal. Bulking up the protein and vegetable portion of the meal, whilst reducing the carbohydrate serving is an easy way to ensure your athletes are getting adequate recovery from training and maintaining a high metabolism.

This is not to say that all carbs should be banned; they’re of vital importance in maintaining the energy levels needed for training and providing the energy for the body to process and utilise vital proteins.

In fact there is limited scientific evidence to suggest that slashing carbs leads to sustained weight loss. However, large carb servings are an easy place to start when it comes to trimming down the calorie intake without the athlete feeling a noticeable difference.

Cut out ‘empty calories’

Drinks high in sugar (soft drinks, fruit juices etc) can easily be cut out and replaced with low calorie cordials, diet drinks or ideally just water. At the very least fruit juices can be watered down. High sugar drinks have high calorie contents but will not make you feel any fuller for a sustained period of time over the diet alternatives due to a high rate of intake of fast-releasing sugars. The same goes for sweets and chocolate bars, which can be swapped out for fruit, nuts, high protein muesli bars and dried fruits,

Stay well hydrated in the lead-up to weigh-in (and in training)

This helps for a variety of reasons. In part it will help the athlete feel fuller when their food intake is reduced. Proper hydration also helps to maintain a high metabolism in the long-term and can have other short-term benefits in the lead up to a weigh-in that I’ll cover later on.

Most importantly, proper hydration is absolutely necessary for effective training. Each athlete’s hydration needs will vary depending on their sweat rate and how much sodium they lose in their sweat. Everyone loses a different amount of sodium in their sweat. At Precision Hydration, we see athletes who lose from as little as 200mg of sodium per litre of sweat to as much as 2000mg/l. This is largely genetically determined.

Sweat rates also vary from person to person of course; and from situation to situation for any given person (from almost nothing in cooler conditions and at low intensities, to several litres per hour during intense exercise in the hot conditions of a dojang).

When you combine differences in sodium concentration with those in sweat rates, the potential variance in the total net sodium losses experienced from one athlete to another can be really significant.

And, in a lot of cases, those losses are many times higher than someone who’s not sweating on a regular basis. This is why the standard government guidelines for sodium consumption should be viewed cautiously by athletes. It’s more than possible to lose the daily 2,300mg of sodium recommended by the existing government guidelines in just 1 hour of exercise, if your athlete sweating heavily and sweating out lots of sodium. Their loses during a longer period of exercise really can be massive.

Your blood volume is gradually reduced as your sweat losses increase. That’s because sweat is drawn from your blood plasma. This increases the strain on your cardiovascular system, making it harder to pump blood to your skin to cool you down and to your working muscles.

Other issues such as a general feeling of fatigue and muscle cramps can also be experienced if losses are allowed to go uncorrected for long enough, or if significant imbalances between fluid and sodium are allowed to occur.

Up to a certain point, taking in plain water is enough to mitigate sweat losses. But, as those losses start to mount up, you need to replace sodium too to avoid your blood becoming diluted.

To help your athletes figure out how much sodium they might need to be taking in in different training and combat scenarios, get them to take our free online Sweat Test. This will provide them (or their parent, or you as their instructor) a personalised hydration plan with guidance on what, when and how much to drink.

If your athlete (or their guardian) decides they’d like to implement their personalised strategy, British Taekwondo members can get 15% off their first order of our all-natural, multi-strength electrolytes by using the code TAEKWONDO.

Don’t compromise pre-session fuelling or post-session recovery

When trying to drop weight there are areas where food intake can easily be reduced, but pre and post-session intakes are indispensable. If your athletes are unable to train properly then they’re going to lose fights, regardless of their weight category.

Our recommendation is to look at their diet and find other areas to remove or replace food that isn’t going to impact their training. The same goes for post-session recovery, if the athlete doesn’t eat well after a session, the training stimulus and adaptations earned in the session will be compromised.

Short-term weight management guidelines

As I’ve said, the majority of weight loss should be done over a sustained period of time.   But, inevitably your athletes may be tempted to engage in shorter term weight management practices in order to make weight. This can be acceptable if done in a controlled and sensible manner.

Sweat/sauna sessions

Sweat sessions can be quite useful in preparing to make weight, as long as they are conducted safely. In the interest of athlete welfare, it’s important that body weight losses are monitored continually during such sessions and that the sweat response is kept under control.

Heat sessions should not to be used for long-term weight loss as this would involve regular and serious dehydration. For many athletes, it’s acceptable to lose a kilo or two of body fluid in a heat session, but as a general rule no more than a 2% of body mass should be lost. Following a sweat session, ensure the athlete submerges in a cold spa, or takes a cold shower, as this will stop the sweat response from continuing uncontrollably and the athlete losing more fluid and electrolyte than they realise.

Pre weigh-in hydration

It’s can be easy to lose between 1 and 2 kg the night before a weigh-in in a safe manner. But it’s critical to stay well hydrated in the days and weeks prior to this. The body’s renal system is very efficient, but also fairly simplistic. In a nutshell, in order to maintain the correct water levels in the body, the more fluid that’s put into the body, the more that will be expelled by the renal system.

This can be exploited to achieve large, short-term losses in water weight. By staying properly hydrated in the few days before a weigh-in and then suddenly dropping fluid intake, the renal system can be ‘tricked’ into thinking it still needs to expel fluid, when the fluid intake has actually stopped. Put simply, the system has a fluid retention ‘lag’.

Despite the renal system being useful to us when we want to lose weight rapidly, it can be harmful when trying to rapidly rehydrate after a weigh-in. A large increase in the fluid input will result in a large increase in the fluid output, and it is often possible for the output to be greater than the input. To account for excess urine losses, the National Athletic Trainers Association recommends that fluid input is increased 25-50%.

Post weigh-in hydration

It’s far too easy to get excited and gulp down litres of sports drink, but all this will do is make your athletes feel sick before the fight, which will have a negative impact on their mental preparation.

Small and regular fluid intake is a more appropriate approach to take. A very simple rehydration protocol can get athletes from dehydrated to ‘competition ready’ (with no negative effect on performance) in about two hours.


Avoid Diuretics

Another worrying trend amongst weight category athletes is the use of diuretics and/or laxatives. What must be stressed here is that diuretics come under the World Anti-Doping Agency list of banned substances, and must therefore be avoided – no exceptions. Certain food and drink will naturally increase urine output which is perfectly legal and acceptable. These include diet soft drinks, black tea, and dried fruits. As always, the important thing is to keep the increased urine output under control.

Hopefully this blog will help you help your athletes engage in safe and sensible weight management practices so that they perform at their best in the right category for them. If you have any questions at all, just drop us an email at