Safety, thirst and always, hydration and exercise

The arrival of summer, coupled with the growth of outdoor training and adventure fitness, makes a refresher on the topic of hydration useful for every fitness professional, says Rob Shackleford.

In terms of human survival, the 'rule of three' is often cited. Three minutes without air; three days without water; three weeks without food. After that… well, there is no 'after' that.

Most of us in the developed world are fortunate enough never to have experienced anything more than mild hunger pangs, and are seldom placed in situations that restrict our access to air. But, while getting nowhere near the three day mark, the issue of adequate hydration still presents a degree of challenge to many people.

Water and the body

Naturally, water is the most important requirement for achieving hydration. In the body, water's functions include regulating temperature to our preferred 37 degrees centigrade, lubricating joints, and transporting both nutrients and waste through the body.

Dehydration occurs through inadequate fluid intake to balance the body's normal process of sweating and expiration; each day we expel about two cups-worth of water through breathing alone. Water is one of the most important nutrients in the body, making up approximately 70 per cent of muscle, and about 75 per cent of the brain. Some research illustrates a link between pain and disease and chronic dehydration, with the body manifesting its shortage of water in discomfort such as headaches and muscular pain. The early stages of dehydration, however, carry no obvious signs or symptoms.

Hydration in sport and exercise

In the worlds of sport and exercise the risk of poor hydration is ever present. For any athlete, hydration status is a key factor affecting overall athletic and mental performance, with research showing that mental cognition and physical attributes such as strength, power and endurance all decrease with poor hydration. Fluid loss is even more pronounced when exercising intensely, especially at altitude or in hot, humid conditions. When an athlete loses as little as two per cent of body weight through water loss, results include a drop in blood volume, causing the heart to work harder. Even at a loss of two per cent, performance will decrease by between 10 and 20 per cent – so staying hydrated is particularly important during exercise or competitive sport when you need to perform at your peak.

Prevention and rehydration

If not addressed, dehydration and the loss of valuable electrolytes such as chloride, calcium, magnesium, sodium and potassium can lead to fatigue and medical complications, such as heat exhaustion, heat stroke, heat/muscle cramps, and, in extreme circumstances, coma leading to death.

The correct amount of fluid needed to rehydrate your thirsty body depends upon a variety of factors, including the length and intensity of exercise and personal metabolic differences. While the oft-cited rule is to not wait until you feel thirsty before having a drink, there are two simple methods of estimating adequate hydration:

  1. Monitor your urine volume and colour. Large quantities of light coloured, diluted urine indicates you are well hydrated, while dark coloured, concentrated urine probably means you are dehydrated.
  2. Weigh yourself before and after exercise. Any weight lost is likely from fluid, so try to drink enough to replenish losses. Any weight gain could mean you are drinking more than you need.

While adequate fluid intake is essential to comfort, performance and safety, the longer and more intensely you exercise, the more important it is to drink the right kind of fluids to ward off dehydration.

The most obvious choice is to drink water, and for most people engaging in normal daily routines and exercise, water is best. Caffeinated beverages and alcohol contain substances that actually cause dehydration, so should be avoided, as should carbonated drinks, which may cause bloating or a feeling of fullness preventing adequate fluid consumption.

a question of purity

Though essential to hydration, water can also be a danger when its purity is in question. Nothing kills an adventure fitness experience or sporting trip like a dose of diarrhoea, and in many parts of the world where such activities are popular, good water can be hard to find.

While bottled water is often available in such destinations, another option is to take a personal water filter such as a Lifestraw ( that makes it safe to drink the local water – even from a local creek or puddle. This apparatus enables the drinking of water with confidence as it filters out all biologicals and dirt, while also removing the need to carry heavy bottles of water and reducing the waste associated with disposable bottles.


Sports drinks: solution or problem?

The need for carbohydrate and electrolyte replacement during exercise depends on the exercise intensity, duration, climatic conditions and individual differences in sweat rates. Tapping into this need for athletes to be hydrated and adequately fuelled during exercise, there is now a competitive market in beverages marketed with reference to sport or performance. If you're an elite athlete, it is possible that consuming sports drinks before and during an event might make the difference between remaining hydrated and becoming dehydrated; between gold and merely competing. Sports drinks are designed to provide the right balance of carbohydrate and fluid to ensure they are emptied quickly from the stomach and rapidly absorbed from the small intestine, making them potentially beneficial for athletes who exercise at high intensity for 60 minutes or more.

For most people, however, these products are just another soft drink containing sugar and salt that we don't really need. It is worthwhile warning clients to beware the hype, as many brands specifically target kids, despite young athletes not needing these drinks. Commercial sports drinks are bad for the teeth and are, arguably, contributing to the growing problem of childhood obesity. It's really not necessary to replace losses of sodium, potassium and other electrolytes during 'normal' training, since you're unlikely to deplete your body's stores of these minerals. If, however, you find yourself exercising in extreme conditions over three or five hours (such as a marathon, Ironman or ultramarathon) you may want to consume a complex sports drink with electrolytes.

A word of caution

It is worth reminding clients that when it comes to hydration it is possible to over-hydrate. Although rare, athletes can drink too much water and suffer from hyponatremia (water intoxication). Drinking excessive amounts of water can cause a low concentration of sodium in the blood – a serious medical emergency usually only seen in cases of burns, serious illness or organ failure.

By advising clients – particularly athletes and those who take part in outdoor and adventure fitness – to monitor the liquids they consume, and to be aware of the signs of dehydration, you can help them safely enjoy their training while also maximising their performance.

Rob Shackleford, BA BBus Hons
Rob is director of LifeStraw Australia, a humanitarian fundraising company targeting the international clean water crisis. Having travelled extensively, Rob has experienced first-hand the importance of clean water for those living in developing nations and has worked with Australian fitness institutions in sponsoring water projects in Africa and Asia.