‘…But I’m not thirsty… ’ a common response from my students on outdoor activities when asked to have a drink!  Dehydration is one of our foremost concerns working in the tropical climate.  Consequences range from mild dizziness to death, but are easily avoided by staying suitably hydrated.  On average, a person should drink at least 2 litres of water a day, requiring additional water for any strenuous activity.  This amount will vary depending on the length of the activity and the amount the person sweats.  To combat this, we always insist on regular water breaks whatever and wherever the activity is.  Another factor often overlooked is the replacement of vital salts lost in sweat.  In extreme cases, by drinking too much water without replacing lost salts, mineral levels can drop so low that they result in a condition known as Hyponatraemia (Low Sodium Levels).  Again, this is easily avoided by replenishing lost salts with an electrolyte beverage, containing valuable salts, and sometimes sugars for extra energy.  To encourage regular drinking habits it is important to make drinking as easy as possible.  Sports bottles now come with a pop out spout, and water bladders (such as the camel-back or platypus) are excellent.  The size of the container should be capable of carrying at least 1.5 litres, but also should not be so large that it becomes a burden to carry.  There are several ways of checking dehydration, either by pinching the skin on the back of your hand and seeing how quickly it returns to its original state, or urine colour, orange being bad, clear being good!  In summary avoidance is always the best action.  Always carry a full water bottle, and drink from it regularly and refill it often so that you don’t get caught out!