Don't Sweat The Small Stuff - The Importance of Sweating

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21st April 2010

Article from Garrards Horse & Hound Autumn 2010

Why is sweating important for horses?

The purpose of sweat is to maintain body temperature within normal, healthy limits.In order for the horse to sustain metabolism and derive energy required for movement, feed must be converted into fuel to feed working muscles and organs.

The conversion of the feed into fuel is very inefficient and results in the production of heat. To remove this heat, horses produce large volumes of sweat which aids cooling by evaporative loss from the skin surface. This process exerts a cooling effect while reducing the horses' core temperature. It must be considered that when horses' exercise at high intensities, this process is exaggerated and may result in increases in sweating rates by up to 15 litres per hour.

 

What is horse sweat made up of?

Sweat is predominantly made up of the electrolytes (salts); sodium, chloride, potassium, lesser amounts of calcium, magnesium, sulphates and phosphates and also contains small amounts of protein.

The concentration of electrolytes in horse sweat is much greater than that of blood plasma, making the horse more susceptible to sweating than other mammals such as humans. Important to consider is that the concentration of electrolytes within sweat will vary depending on the exercise being carried out and that those electrolytes are not lost in equal concentrations.

In addition to electrolytes, horses sweat also contains protein, inclusive of the protein latherin, which aids dispersal of sweat over the skin to maximise the surface area available for evaporative cooling. This is of great importance as evaporation of sweat form the skin is responsible for 60-70 per cent of cooling, while other mechanisms such as increased respiratory rate ('blowing') after exercise provide further relief and evaporative losses.

 

Where are electrolytes stored in the body?

Electrolytes are contained within all the compartments of the body, however the only 'stores' of electrolytes are held within the hindgut, which serves as a vital reservoir for fluid and electrolytes.

 

How crucial are electrolytes?

Electrolytes are essential to normal body function and are responsible for -

  • Nerve and muscle interaction via electrical impulses
  • Cardiac function and integrity
  • Skeletal muscle action and efficacy
  • Regulation and distribution of fluid throughout the body
  • Adequate hydration/prevention of dehydration
  • Co-ordination
  • Prevention of metabolic distress - poor performance, fatigue, heat stress, anxiety, incoordination, poor recovery

 

Sweating occurs more in hotter climates, particularly when the horse is acclimatising and also in high humidity, when sweating becomes less-efficient due to reduced evaporative cooling.

Electrolyte supplementation will aid in maintaining fluid balance and hydration, while also promoting fluid intake. However, other factors associated with sweating losses may compromise the physiological processes of the body. Fluid loss via sweating acts to reduce total blood volume, decreasing the availability of nutrients transported to working muscles and organs throughout the body. This can lead to detrimental effects on key performance factors such as muscle function, nerve transmission and gastro-intestinal absorbtion. Therefore ensuring adequate fluid intake following exercise via electrolyte supplementation will aid in replenishment of exercise induced deficits, quickening the recovery process to enable optimal future performance.

Taken from Garrards Horse & Hound - Autumn 2010