Fluids for hydration and cooling down

Maintaining hydration is important for performance. Fluid intake before, during and after exercise is especially important in hot climates. Salt replacement is important when sweat losses are high. Your hydration strategy should complement your food fueling strategy and your nutrition can be consumed in fluid or solid form.
As with nutrition, the body can be trained to utilize fluids optimally during exercise and overhydration is just as dangerous for an athlete as dehydration. Overhydration often occurs when too much fluid is consumed without replacing salts, therefore drinks that contain electrolytes, whether it is a specially formulated sports drink or a mixture of water with electrolytes (such as REHIDRAT®) is important.

Your fluid needs will depend on a few factors such as your weight, personal sweat rate, the climate (heat), and the intensity and duration of exercise. It is important to drink according to a plan, practice hydration strategies during training and reflect on what works best for you in particular conditions.

How much fluid do I need?

The hydration guidelines below are for endurance training sessions or races that are longer than 2 hours (including multi stage races):

How much fluid do I need?
An individualised approach is important!

Before a race: Test fluid strategies during training leading up to the event to determine your fluid needs, but as a rough guide consume 5 - 10 ml of fluids per kg body weight OR 400 – 500 ml in the 2 hours leading to the start of a race.

During a race: The best way to determine how much fluid you need is to determine your sweat rate. Weigh yourself before and after a long training ride. The aim is to not lose more than 2% of your body weight and your fluid needs can be tailored based on weight loss / gain after exercise.
Alternatively use these guidelines as a rough guide:
● Approximately 5 – 7 ml per kg of body weight every hour.
● OR 400 - 600 ml every hour (100 - 150 ml or 2 - 3 sips every 15 - 20 minutes).

After the race: Determine your needs prior to the race (during long endurance training sessions or races leading up to the event). Have 1.2 - 1.5 litres per kg of weight loss. Check urine colour, dehydration is indicated by dark coloured urine.

When do I need to start hydrating?

As with eating, don’t wait too long before starting to drink fluids. A practical guideline is to have 2 - 3 large sips of fluid every 15 - 20 minutes of activity. Small amounts of fluids are better tolerated than larger volumes during a run.

What should I have?
Before a race: Fluids containing a combination of electrolytes and other nutrients can be used such as dairy drinks, smoothies, fruit & vegetable juices or water with electrolytes. Depending on individual tolerance, caffeinated beverages can also be consumed (1 hour before the start). 

During a race: During endurance races longer or exercise sessions longer han 2 hours, drinking fluids containing electrolytes is important. Using drinks that contain carbohydrates can complement carbohydrate intake from food to reach your fuel goals. Sports drinks or powders containing easy to digest proteins such as peptide proteins can also be beneficial for ultra endurance or multi stage races. Caffeine* should be used sensibly during long races and tolerance tested during training. Start using caffeine 2 - 3 hours into the race.
Having drinks that are cold are better tolerated and help to cool down the body’s core temperature. If you have access to a fridge or freezer, mixing and freezing bottles the night before is helpful. Also be mindful of how practical your race day fluid strategy will be and consider a hydration pack if needed, or support on route to provide cool drinks (if allowed).

After the race

Fluids can help you replenish lost stores of fluid, carbohydrates, protein and electrolytes (salts) after long endurance races. Specially formulated recovery drinks are convenient options containing all these components, but food sources such as dairy products can also provide the body with the same nutrients. Flavoured milk contains a carbohydrate to protein ratio that is ideal for recovery, as well as calcium, magnesium and sodium. Smoothies and dairy drinks such as drinking yoghurt are also great alternatives. If you don’t consume dairy products, smoothies made with a combination of fruit, nuts, nut- or soy milks or vegan protein powders are good alternatives.
*If you are a competitive sportsman, note that certain organisations or sporting bodies may prohibit the intake of large doses that produce urinary caffeine levels that exceed a specific amount

Will my fluid requirements be the same if I do a short run or take part in a fun run? 

For a healthy adult with reasonable fitness that starts the race well hydrated, small sips of water during the run will suffice. If it's very hot and fluid intake increases during the race, ensure that fluids containing electrolytes are consumed during and after the race. Generally you won't need energy or sports drinks during short runs, especially if you had a small meal or snack before the race started. If you are doing a short run at a high pace, simply washing your mouth with a carbohydrate drink can help to improve performance.