Our Western Australian climate makes dehydration, or not having enough fluid in your body, arguably the greatest risk faced by bushwalkers. It can quickly lead to a life-threatening situation.

Water drops on gum leaf DO

Being properly hydrated helps your body function at its best. Dehydration can cause headaches, fatigue, crankiness and poor concentration. Walking in hot weather without adequate fluid intake can quickly lead to heat exhaustion, or worse, heat stroke.

Drink plenty of water (about 0.5 litre) before you start your walk, then drink regularly during the walk to put back what you lose through sweat. We often don’t feel thirsty even when we’re dehydrated, so it’s wise to drink water regularly even if you aren’t thirsty. And plain water quenches your thirst without giving you all the sugar and additives found in fruit drinks and juices, soft drinks, sports drinks and flavoured mineral waters.

Sports drinks which contain electrolytes have been shown to have benefits when you exercise intensely for more than one hour which might apply during a very energetic bushwalk. Sports Medicine Australia says that while water replaces lost fluids, sports drinks (containing 4% - 8% carbohydrate and small amounts of the electrolytes sodium and potassium) also provide additional energy and salts. But flavoured drinks, including sports drinks and low concentration cordial, may encourage more fluid consumption than plain water because of their taste and sodium content.

One way to check if you are drinking enough during a walk is to check the colour of your urine during a nature call. Generally, if your urine is clear or straw-coloured, rather than yellow, you are sufficiently hydrated.

Do not wait until you are thirsty before you drink! When we feel thirsty and are in need of a drink; we are already dehydrated. If you get a headache while you’re hiking, don’t ignore it. When dehydrated, your best course of action is to have a rest in the shade, have a drink and give your body a little time to become rehydrated.

But beware hyponatraemia - when too much of a good thing can go badly wrong! Drinking excessive quantities of water, faster than you lose fluid in sweat and urine, can result in over-hydration and low blood sodium levels, hyponatremia. On very rare occasions this can result in coma and even be fatal. Hydration bladder users should be a little cautious about drinking too much too often. It’s quite adequate and potentially safer to drink a little less frequently but in more known amounts from a water bottle.

Incidentally there is no hard evidence that sports drinks, salt tablets or eating salty snacks, or even keeping hydrated will prevent painful cramps during a walk. All these things may help, but probably the most effective way to minimise the chance of a cramp is for walkers to build and maintain good muscle strength and fitness; fitter muscles are more resilient to fatigue and cramp.