'The balance of electrolytes is closely tied to the balance of water in the body as one affects the other," explained Ms Teo Kiok Seng, nutritionist at Nutrition Network Services.
'Very small changes in electrolyte levels in the various fluid compartments in our body cause water to move from one compartment to another," she said.
With water being a major component of organs and tissues, electrolytes such as sodium, potassium and calcium are vital for numerous bodily functions.
Other than helping to maintain optimal heart, brain and muscle functions, these electrolytes are also involved in oxygen delivery and in regulating the body's pH levels, said Ms Jaclyn Reutens, a dietitian at Aptima Nutrition & Sports Consultants.
The pH is a measurement of how acidic or alkaline a solution is.
'Hence, dehydration or over-hydration can result in electrolyte disturbances which can lead to life-threatening medical emergencies, such as irregular heartbeat," added Ms Reutens.
Water and electrolytes are lost throughout the day via urine, stools, sweat and breathing, and must be replenished by consuming the right kinds and amounts of food and beverages.
Ms Teo recommended eating plenty of fruits and vegetables in addition to drinking water and other beverages.
'Fruit and vegetables are particularly good sources of water so make sure that you include them in your daily diet," she said. 'For example, water makes up 90 per cent of watermelon."
However, you should not count beverages such as coffee and alcoholic drinks as part of your daily fluid intake. This is because caffeine is diuretic - it promotes urination while reducing your urge to drink. Alcohol inhibits the action of the anti-diuretic hormone, which prevents too much water from being lost through urination, said Ms Teo.
To replenish electrolytes, quick fixes such as a cheese sandwich with wholemeal bread, a chicken sandwich with a banana smoothie or a sports drink can do the job, said MsReutens.
Such replenishment is even more important after exercise, as additional water and electrolytes will be lost through sweat.
'If you exercise, drink up to an extra 1litre of water. If you sweat heavily, take 750ml of sports drinks to replenish water and electrolyte loss," she advised.
Older people should also take extra care to keep themselves hydrated. This is because people become less sensitive to the sensation of thirst as they age. Their kidneys also function less well, said MsTeo.
'A simple way to check if you are drinking enough fluid is to check the colour of your urine," she said.
'The more transparent it is, the more hydrated you are."
Source: The Straits Times/ Mind Your Body by Poon Chian Hui