180317 Fluid replacement-Water and the body-why we need it
Water “serves as the body’s transport and reactive medium: Diffusion of gasses always takes place across surfaces moistened with water. (Page 53 reference # 1)
- Nutrients and gases are transported in aqueous solution.
- Waste products leave the body in urine and feces
- Water has tremendous heat-stabilizing qualities because it can absorb considerable heat with only a small change in temperature.
- Water lubricates joints
- And finally because it is essentially incompressible it helps give structure and form to the body through the turgor (the normal fullness of the blood vessels and capillaries) it provides for body tissues.”
- Dehydration and its effects on the body.
Most studies relating to dehydration have been conducted for sports or military related reasons, but the results are the same; the body has to have fluids to run efficiently. It needs to replace these lost fluids in order to remain cool enough to properly function. If not, then heat builds up. The body attempts to lessen this raising of the core temperature by various mechanisms such as breathing faster or sweating more. If enough sweat is produced, dehydration cannot be far behind.
Sweat causes the body to lose electrolytes specifically sodium, potassium, chloride and magnesium. Each one of these electrolytes has an impact on, and is crucial to muscle and nerve activity. (Page 246 reference #2)
Therefore, lots of sweating over long periods can, and will, affect your ability and level of mental and physical performance. In fact, if sweating is heavy enough for an extended time (several hours) sweat fatigue may result. Sweat gland fatigue can cause an inability of the sweat glands to regulate core temperature. This is the body’s main mechanism for heat dissipation; should it be disrupted serious consequences result. (Page 408 reference #1)
Our body mass consists of 40-60% water, with muscle containing about 65-75% water, and fat having about 50% water. Excessive water/electrolyte losses impair heat tolerance and physical performance. This can lead to severe dysfunction in the form of heat cramps, heat exhaustion and finally heat stroke, which can be life threatening. (Page, 51-reference #1)
Much of the fluid loss is called extra cellular, meaning fluids that surround and bathe the cells (blood plasma, lymph, saliva, fluid in the eyes, fluid secreted by the glands, fluid that bathes the spinal cord and fluid excreted from the skin and kidneys). Blood plasma accounts for 20% of the extra cellular fluid (between 3 and 4 liters). (Page 53 reference #1)
Continued next week.