What should I take with me when hunting in extreme heat? How should I carry my water? How do I know when heatstroke is setting in? Jonny Crockett answers all these questions and more

Everything looks better when it’s sunny: a bit of warmth to the old bones, bright, long days and the feeling that all is right with the world. But take it to extremes and the blazing sun can be a killer. If you’re seeking warmer climes for your sporting endeavours then you should think long and hard about your preparation.

Let’s talk biology first. The heat at the equator has extraordinary effects on your body, mostly to do with hydration. When the heat rises, your core temperature rises too. This can give you heat exhaustion or heatstroke.

Heat exhaustion is caused when the sufferer has sweated to excess and has lost their healthy levels of electrolytes, often through intense exercise in hot and sunny weather. Their symptoms will often include a pale face, strangely cold skin, a weak pulse, dizziness, weakness, cramps, delirium and eventually unconsciousness and death. Cheery, hey? It’s no laughing matter though. They need to be moved to the shade or a cool place as a matter of urgency. The electrolyte imbalance has to be restored immediately. They should take cool (not cold) water with electrolyte powder or tablets dissolved in it. Do not let the sufferer gulp the drink. Many sips are better than a few mouthfuls. Get them as cool as possible, and if they’re feeling dizzy, lay them down and raise their feet. You must get advice from a qualified medical professional and medical treatment. This is a serious condition.

If the body temperature rises above 40.6ºC then the sufferer could well have heatstroke. Unlike heat exhaustion, the sufferer will have hot, dry skin and a flushed feverish face. The pulse will quicken and be accompanied by an acute headache, followed by a period of vomiting and then unconsciousness. It is imperative that you reduce the body temperature quickly. Cool the body with cool water, fanning and soaking any loose clothing. Give the sufferer water to drink and get them to rest until recovery is evident. Medical assistance should also be sought.

With both heat exhaustion and heatstroke, the urine output will be reduced and the colour will change. If possible, the colour of the urine should be checked. It should be a light straw colour and not a deep yellow that looks like you’ve been drinking highlighter fluid! You shouldn’t move on again until the urine output is back to the light straw colour.

Next, we should look at fitness. This will help in staving off heat exhaustion and heatstroke. Individuals will vary enormously, but as a rule of thumb, you should be able to walk five to 10 miles, three times a week with no real difficulty. This will ensure that you have the core strength to cope with the exertions of hunting in hot climates. A good diet is also important. Now this might sound strange but you need to have sufficient fibre in your diet. This is more to do with travelling than hunting, but after days of a full bowel, the aim will suffer. When travelling, if you have not had a ‘movement’ for three days then you should take action with laxatives. If left untreated, constipation can lead to a perforated bowel. If your body is at ease, then your ability to stalk and hold your rifle will be easy too.

Your liquid intake should be mixed and varied too. Water should be your main drink. Just plain old water. However, water can get very boring, very quickly. A bit of squash is excellent. Tea and coffee are diuretics but still have enough benefit for you to drink plenty. Alcohol, while infinitely more popular, should be limited and perhaps saved for another time. Alcohol withdrawal is best avoided when trying to bag your first kudu; hangovers are never a positive thing with firearms anyhow. You should certainly be drinking plenty of clean water, but be careful not to drink too much water. You can flush out all your electrolytes and salts and make yourself extremely ill. Too much water can lead to kidney failure. If you are thirsty then drink, but keep it to advisory limits.

Make sure your water is clean, though. The five basic contaminates of chemicals, bacteria, viruses, parasites and turbidity should always be removed. You can do this by safe sourcing (bottled water with unbroken seals) or by filtering and boiling for four minutes. The four minutes is important, especially if you don’t know your altitude. Imagine that there is a column of air above your water as it is boiling. The air pushes down on the surface of the water. The greater the weight of air, the more difficult it is for the water to escape the surface. In other words, the more energy it takes for the surface to break into a boil. This means that it takes more heat to boil the water. Therefore, the greater the weight of air (or the lower the altitude), the hotter the boiling point of water. At sea level this is 100ºC. At that temperature, you are killing bacteria and viruses at the best rate you can. However, you may not know your altitude. If you are at a higher altitude, you have less air above you, so the boiling point of water decreases. To ensure you have pumped enough energy and heat into the water, you’ll need to boil the water for longer. As a rule of thumb, as the boiling point of water decreases by 1ºC you should boil the water for a further minute. See left for a rounded-up (for safety) table as a guideline. In essence, for every 300m (1,000ft) you should add one minute to your boiling time. You’ll know when you are above 1,000m as the plants will be different and the temperature will drop. We’re looking at an altitude similar to the top of Mount Snowden to Ben Nevis. You should be able to get your altitude from the contours on your map.

At this point, it should be noted that boiling occurs when the whole surface of the water is disrupted, not just bubbles forming on the bottom and sides of the pot [see picture left].

Choose your water carrier carefully. There are two sorts: an ordinary bottle system and the ‘bladder’ (large ziplock bag) system. There are pros and cons to both systems and, as the lists below show, it’s horses for courses really...

Water bottle system – Pros

* You can actually see how much you have drunk, so you can monitor your input

* It is easy to fill from another bottle or purification system

* Usually tough and resilient

* Can sometimes be used to keep water hot or cold

* Easily cleaned so there is no problem with adding electrolytes or flavours

* Ceap and readily available

Water bottle system – Cons

* Easily spilt

* Cumbersome to frequently remove from backpack and put back – not the easiest when on the go

* Takes up the same amount of space when travelling with it empty as when it is full

Bladder system – Pros

* Easy to drink on the go

* Can be put on your back or inside backpack

Bladder system – Cons

* Difficult to clean

* Ideally for water only, not electrolytes, squash, etc.

* More likely to split than a bottle

* Hose freezes more quickly in very cold weather (extreme altitude or cold climate)

* More expensive

Travelling to hot climates will require medication that you would not normally take. I can’t stress enough how important it is to get qualified medical advice on this; it really is worth doing your research and visiting your doctor’s surgery. Medical risks will vary depending on your location, but it is always better to be safe than sorry. If you aren’t happy with your doctor’s advice, get a second opinion. Keep asking until you are happy that you are covered. Some medication can be very expensive and have side effects.

When on a trip to a hot climate, you may well be advised to take malaria tablets. These can have the following effects on eyesight, which could impact your accuracy:

* Anti-malarial drugs, including chloroquine, quinacrine, and hydroxychloroquine, can cause changes in the cornea. Symptoms such as halos around lights, glare and light sensitivity may occur. There is no change in the person’s visual acuity. Once drug therapy is stopped, both subjective symptoms and objective corneal signs disappear.

* Quinine may (rarely) affect night vision.

* Chloroquine may lead to retinal detachment, degeneration of the optic nerve, reduced colour vision, blind spots, and blurred central vision. (This may be related to the total amount of the medication taken over time.)

* Quinine, taken by pregnant women, can lead to optic nerve hypoplasia in the foetus, which is an under-developed optic nerve

* Anti-malarial drugs contribute to sensitivity to light

Don’t forget to take your usual medications and painkillers. Beware of taking Imodium: what is coming out quickly is meant to be coming out quickly; keeping it in isn’t necessarily the best plan.

In hot climates you get an increased chance of annoying buzzing insects. Take plenty of insect repellent. The only known proven insect repellent is DEET. There are plenty of anecdotal stories to promote other repellent, such as Avon Skin So Soft (works for five minutes then needs reapplying), Citronella (at least you smell nice) and others that make grand claims, but essentially they are not repellents, just masks. Masks do not last very long and insects adapt to see through masks very quickly. DEET repels where others don’t and I haven’t seen any authenticated evidence to the contrary.

Hot and damp conditions can very quickly lead to skin rot. When travelling to these environments, I take an anti-fungal talcum powder. It is good for other areas, too. When you get a chance, give yourself a good airing. There is nothing quite so exhilarating as flashing your delicate areas to a charging hyena.

Clothing choices

Selecting the correct clothing is all-important. Remember that you’ll take a few days to become acclimatised. Fifty years ago, Hollywood gave us the image of the ‘Great hunter’ and the image was based on what people actually wore because that’s what worked. A broad-rimmed hat is essential. It keeps the sun out of your eyes and off your neck at the same time (don’t forget that can actually happen on the equator). Personally, I prefer a leather hat but other hats are available and can be eaten by elephants. Sunglasses are extremely important. They will help prevent headaches and will protect your corneas from UV damage. Ask any optician, sunlight destroys eyes. A lightweight, long-sleeved shirt will prevent burning and also keep insects at bay; some now have UV ratings.

A bit of research is a good idea here. A couple of pockets here is also good. Another handy tip is to have a neckerchief. Picture the scene: you’ve spent all day stalking the beast of your dreams, it’s hot, too damn hot! You’ve finally got yourself into position. Only now does that bead of sweat start to run down your forehead and your scope mysteriously mists up. Rather than wave your arm around to wipe everything clean on your sleeve, the neckerchief is discreet and convenient.

Long trousers will prevent thorns scratching, insects biting and sunburn. Again, make sure that they have good pockets and are going to be tough enough to do the job. Choosing the right colour for the terrain is also important, not just for the trousers, but the shirt too.

Finally, take the best pair of boots you can afford. I’ve left this until last because boots are almost as individual as fingerprints. Personally, I’d go for high boots (keeping snakes and scorpions in mind) that come most of the way up your calf. Again, I prefer leather but a good-quality canvas will do the trick. Good ankle support and a stiff sole is important too. The grip on the sole is down to individual choice, but just because your trip is a hot one, doesn’t mean that it won’t be wet at times. A deep tread is going to stand you in good stead.

There are other items that you could take to back up your trip. Consider taking:

* Satellite phone (available for hire)

* GPS

* EPIRB (Emergency Position Indicating Radio Beacon)

* Handheld weather station

* Pair of binoculars (again, the best you can afford)

* Camera

* Back-up external battery (20,000mAh) for your electrical items (you could go solar-powered on a hot trip)

* Flash drive with copies of documents

* A $100 bill tucked between the sole and inner sole of a boot. This can get you out of all sorts of trouble. But never spend it unless it’s an emergency.

If you are embarking on a shooting trip to somewhere hot and sunny, please enjoy yourself, keep safe, keep hydrated and please don’t tell me... jealousy is such an ugly thing!