Heat Stroke - minerals needed for rehydration

With many parts of Australia hitting record temperatures this summer, it is important to stay well hydrated and keep cool. But sometimes drinking water simply is not enough, as too many electrolytes are lost through excessive sweating – potentially leading to dehydration or other more series heat-induced illnesses such as heat stroke and heat exhaustion.

Heat stroke vs. heat exhaustion

These are two related health conditions, caused by an elevation in body temperature which is normally controlled by sweating. Sweating allows our body to cool through evaporation, but if a person has become too dehydrated to sweat, body temperature can rise quickly. High humidity can also prevent sweat from cooling the body, leading to a heat induced illness that can be very serious if not treated quickly and effectively. Normal body temperature is around 37°C, with slight variations in this considered normal.

Heat exhaustion

Heat exhaustion occurs when a person’s body temperature is between 37-40°C. Signs and symptoms include:

• Heavily sweating
• Dilated pupils
• Extreme fatigue due to a decrease in blood pressure and volume
• Faint/dizziness
• Headache
• Nausea or vomiting

Heat stroke

Heat stroke occurs when the body’s temperature reaches above 40°C. It can become a serious and life-threatening condition if not acted upon quickly. Signs and symptoms of heat stroke include:

• Dry skin (lack of sweating)
• Dilated pupils
• Rapid, shallow breathing
• Vertigo
• Confusion
• Headache
• Thirst
• Nausea or vomiting
• Muscle cramps

Who is at risk of heatstroke

People at higher risk of developing heatstroke or at a higher risk of developing complications include:

• Children under the age of two
• Elderly people
• Diabetics who depend on insulin
• People with kidney, heart, or circulation problems
• Athletes and people who perform manual labours outdoors

Preventing dehydration

Preventing excessive loss of body fluids and electrolytes is crucial in preventing dehydration and heat-related illnesses. Dehydration occurs when the body needs more fluids than are being consumed in order to function normally. Our body is composed of about 60% water, while our muscles and brain are composed of up to 85% water. 

As a rule, aim for 8 glasses of water daily, but drink extra with exercise and excessive sweating. It is important to stagger water intake throughout the day and drink whenever you feel thirsty. If you notice a headache or fatigue setting in it may mean you are already dehydrated. Another way to know if you are getting enough fluids is if you are urinating every 3-4 hours. The urine should be light-coloured. If it is concentrated and dark, it means your fluid intake is too low.

What are electrolytes?

Electrolytes are minerals in your body that have an electrical charge. The main electrolytes found in the body are calcium, sodium, potassium, chloride, magnesium, and bicarbonate. About hydration the electrolytes considered the most essential to hydration include potassium, sodium and chloride. Electrolytes are essential for normal functioning of all organs and cells. They are required at specific levels in the body to carry electrical signals, help regulate pH levels and healthy heartbeat rhythm. Organs in the body that require higher amounts of these electrolytes and are therefore prone to damage caused by fluid loss, include the brain, central nervous system, and muscular system.

Chloride and sodium are the bodies principal electrolytes that are found outside the cells and are the first to be lost when fluid is lost by excessive sweating. Chloride aids the body in balancing other fluids and sodium helps the body to retain water.

Potassium is a positive ion found in the inside of cells. Potassium plays a critical rule in muscle health and in regulating heartbeat rhythm. Potassium levels too high or too low can cause changes in blood pressure and can inversely impact the heart rhythm causing it to beat rapidly, slowly, or irregularly.

Magnesium is also needed for muscle health, regulating heart rhythms, nerve function, digestion, healthy mood, and energy levels. If your experiencing muscle cramps, headaches, and fatigue due to the heat, you may be deficient in this mineral.

Sports drinks – are they necessary?

While for the average person battling a hot day, adequate water intake and eating enough nutrients in the diet should be sufficient to prevent dehydration and adverse effects from the heat. However, for those who are outdoors doing manual labour, exercising, and not taking enough preventative measures may be at risk. In this case a good quality electrolyte replacement drink may be necessary. It is best to avoid many of the mainstream products very high in sodium and sugar, many with artificial colours and flavours. There are products available which do not have hidden nasties and are higher in their electrolyte concentrations—making them a much better option to avoid the effects of dehydration in the heat. 

Rehydrate with coconut water

Coconut water from young green coconuts is a naturally rich source of electrolytes such as potassium, sodium, magnesium, and phosphorus. It also contains easy to digest carbohydrates as well as other vitamins, minerals, and amino acids. Research has showed coconut water is just as effective in whole body hydration as sports drinks.

Hydrating foods

It is important to eat plenty of nutrient-rich foods, particularly fruits and vegetables with a high electrolyte and water content. Foods to include in the daily diet include celery, melons, cucumber, kiwi fruit, citrus, pineapple, bananas, and green-leafy vegetables. Other foods that can help replete electrolytes and fluids include fresh fruit and vegetable juices, frozen fruit ice blocks, mineral water with citrus slices, herbal teas and bone or vegetable broths. Calcium rich foods found in nuts, seeds, fish, and dairy products is also recommended to replenish levels of this important nutrient.

The typical Australian diet is often very high in sodium but if your sodium levels are depleted through excessive sweating and you’re not getting enough in foods, adding small amounts of good quality salt in the diet may be necessary. It is also important to note that too much sodium depletes potassium in the body, causing further imbalances.

Other ways to prevent a heat induced illness include:

• Drink less beverages which have a diuretic effect such as tea, coffee, alcohol and other caffeinated drinks
• Wear loose, lightweight, light-coloured clothing
• Wear clothing in natural fibres such as cotton and bamboo which allow your skin to breathe. They also allow sweat to evaporate to cool the body
• Wear protective clothing and sunscreen if outdoors
• Limit physical activity outdoors. Plan this time during cooler times of the day if possible
• Keep cool with fans, air-conditioning, icepacks, cold drinks, cool showers and baths

References

https://www.australiawidefirstaid.com.au/heat-stroke-vs-heat-exhaustion/

Von Duvillard SP, et al. Fluids and hydration in prolonged endurance performance. Nutrition. 2004 Jul-Aug;20(7-8):651-6 https://www.ncbi.nlm.nih.gov/pubmed/1521274

http://nutritiondata.self.com/facts/nut-and-seed-products/3115/2

http://chemistry.tutorvista.com/inorganic-chemistry/list-of-electrolytes.html

Saat M, et al. Rehydration after exercise with fresh young coconut water, carbohydrate-electrolyte beverage and plain water. J Physiol Anthropol Appl Human Sci. 2002 Mar;21(2):93-104 https://www.ncbi.nlm.nih.gov/pubmed/12056182