Hydration – How Much Should You Be Drinking?

Hydration – How Much Should You Be Drinking?

posted in: Obstacle Course Racing | 0

How Much to Drink: A few different ways to decide

OCR Hydration – the general rule of thumb is to consume 500ml per hour of vigorous exercise in addition to the two liters per day.

More specifically based on bodyweight  (.5- 1 oz per pound of bodyweight ) need to drink at least 2.5L – 5L  for 170lb person like Dr. Theresa.

Sweat Test: In practice, the need varies from person to person and the best thing to do is to measure yourself. 

This is quite easy to do with a simple test. One liter of water weighs one kilogram.

By measuring your weight before and after training or a test event and correcting for any fluids taken in, you will get an individual rate of fluid lost for those conditions.

For example, a 70kg athlete who loses 200 grams during a one hour training session whilst drinking a 500ml drink will have a gross loss of:

(Finish weight – start weight) – (weight of amount drink)


69.8 – 70.0 – 0.5 = -0.7kg or -700g

This gross loss is equivalent to 700mL of fluid per hour. This figure would help the athlete plan fluid needs during an event. A further adjustment would be needed if the conditions of the test training were different to the event. A 70kg 2:30 marathon runner can lose as much as 5L (5kg) of body fluid in that time!

–In summary: Fluid intake should not exceed sweat loss

What are electrolytes? 

Electrolyte product options: Nuun, Metasalt, Saltstick

Clean Sports Drinks with electrolyte option: Scratch, Tailwind


Among other things, without electrolytes you wouldn’t move a single muscle in your body. Got your attention?

An electrolyte is any substance containing free ions that behaves as an electrically conductive medium. That means that one of the main functions of electrolytes is to work together to conduct nerve impulses that allow you to contract your muscles. Other functions include controlling fluid balance and regulating certain hormones to name a few.

In our bodies, there are 5 main electrolytes, sodium, chloride, potassium, calcium and magnesium. These are all lost in varying degree when we sweat while exercising. That is why it is important to replace the lost electrolytes during exercises lasting more than 1hr. Most of us have felt it when these are out of balance with symptoms like dizziness and muscle fatigue. Such imbalances lead to serious performance declines. In some cases, it can even lead to hyponatremia, a very serious electrolyte imbalance condition.

Hyponatremia is an electrolyte disturbance (disturbance of the salts in the blood) in which the concentration in the plasma is too low. Over hydrating with plain water, especially during exercise that causes loss of electrolyte through sweat, can dilute essential electrolytes in the body, causing disorientation, illness and in rare cases, death.

For this reason, supplementation is key.


What are their function / Benefits:
o They help maintain muscle function
o They help improve endurance
o They help improve overall performance

Why do Muscles Cramp? –

  • Poor physical state of your muscles (muscle fatigue)
  • Dehydration
  • Electrolyte imbalance