Regular transportation is a common part of the competition horse’s life and can cause water and salts to be lost through sweat.

Standing in a trailer or lorry is not at all the same as standing in a box. One research study showed that horses' energy expenditure during travelling was equivalent to that needed for walking. Rough and winding roads (or poor driving!) will require continuous adjustments by the horse in order to maintain his balance. This burns energy and can result in a very tired horse at the end of a long trip.

Horses with a nervous disposition or those with little travel experience generally stop drinking. These horses will expend more energy and be more fatigued after a trip than the old campaigner.

Research has shown that horses can lose approximately 0.5 per cent of their bodyweight every hour they travel, which is 2.5 litres for a 500kg horse. Much of this loss is due to sweating, and when compounded with the physical tension of constantly balancing themselves, can lead to severe dehydration. Lack of fluid in the gut can lead to impaction, and low fluid levels in the body may cause a horse to tie up or suffer from other muscle problems.