Dehydration in Summer
Extreme physical activity in hot weather signals the body to produce more sweat in order to keep it cool but it also can cause dehydration if water is not replenished.
What is dehydration?

Dehydration occurs when you use, or lose, more fluid than you take in; and your body doesn’t have enough water and other fluids to carry out its normal functions. If you don’t replace lost fluids, you will get dehydrated. Sometimes excessive sweating can lead to a dip in water content in the body. Extreme physical activity in hot weather signals the body to produce more sweat in order to keep it cool but it also can cause dehydration if water is not replenished. Older adults naturally have a lower volume of water in their bodies, and may have conditions or take medications that increase their risk of dehydration. This means that even minor illnesses, such as infections affecting the lungs or bladder, can result in dehydration in older adults.

Three facts to remember about dehydration
  • Dehydration occurs when the body loses too much fluid.
  • Fluid can be lost through illness, sweating or exercise; and the risk for dehydration is higher in summer months.
  • Dehydration can cause muscle cramping.
One reason not to ignore dehydration

As you can see in the picture below, your organs are made up mostly of water. Severe dehydration decreases the fluids in the body. As fluids help the blood to travel to your organs; without this fluid, the body can go into shock and cause serious medical complications.

What are the signs of dehydration?

Mild Dehydration

  • Dry mouth and sticky saliva
  • Reduced urine which is a dark yellow
  • Listless behavior
  • Increased thirst
  • Moderate dehydration

Extreme thirst

  • Dry inside mouth, and eyes will not tear
  • Decreased urination, with urine that is amber or brown
  • Lightheadedness (relieved by lying down)
  • Irritable or restless
  • Arms or legs are cool to the touch
  • Rapid heartbeat
  • Muscle cramps
  • Severe dehydration (Medical Emergency)

Altered behaviour

  • Faintness not relieved by lying down
  • Inability to stand or walk
  • Rapid breathing
  • Weak, rapid pulse
  • Cold, clammy skin or hot dry skin
  • Little or no urination for 12 or more hours
  • Loss of consciousness
Why is it worse for the older adults?

Water metabolism changes with ageing. This is due to a decrease in total body water, decrease in intracellular water, and a decreased thirst perception; thus, making older adults more susceptible and at risk for dehydration and subsequent medical complications.

It is important to note that some medicines may cause dehydration:
  • Antihistamines
  • Blood Pressure Medicines
  • Chemotherapy
  • Diuretics
  • Laxatives
  • Psychiatric medicines
What should you do if you are mildly dehydrated?
  • Rest
  • Take off extra clothes if you are warm
  • Rehydrate with 1.8L of cool liquids over the next 2 to 4 hours.
  • Continue to drink. It may take as long as a day and a half to replace the fluids that you have lost.
  • Consult a professional if you become less alert, dizzy or lightheaded, or if symptoms become more severe or frequent.
What are the potential longer-term effects of dehydration?

Dehydration causes an electrolyte imbalance, with higher amounts of sodium and a lower amount of potassium produced.
A very high sodium level can cause confusion, paralysis, coma, and seizures.
Although there is not an immediate problem, extended time with low potassium levels may produce less insulin, which may increase the amount of sugar in the body.
If the potassium level becomes very low, fatigue, confusion, and muscle weakness and cramps typically occur. A very low potassium level can cause paralysis and abnormal heart rhythms (arrhythmias).

How can I prevent dehydration?

Drink fluids regularly throughout the day

  • 5 glasses of water a day is recommended
  • Men: 2.5L
  • Ladies: 2 L
  • Avoid coffee, alcohol and high protein drinks in large quantities – as these liquids have a diuretic effect, whereby more fluids are expelled from the body at a faster rate.

Dr. Ryan Groenewald is the Practice Manager at Physiotherapists at Home, an incorporated partner of Medwell SA – The Home Healthcare Specialists. For more information visit or

Multiple offices to attend to your enquiries