Training for a Jungle Ultra

Last updated: 10-Mar-21

By James Eacott

I’ve completed one and a half multi-day ultra marathons in the jungle. I say “half” because I followed a successful Jungle Marathon with a DNF at the Beyond The Ultimate Jungle Ultra.

I don’t recall much beyond wallowing in a stream, physically exhausted. I’d not drunk enough and hadn’t consumed enough calories. But more than that, it was my mental game that really defeated me.

I’ve completed multi-day ultras in deserts (Atacama Crossing) and mountains (Everest Trail Race), but I can categorically say the jungle environment is on another level.

It’s flippin’ unforgiving.

In the jungle, distance is meaningless. Wading through swamps, climbing insane gradients and attempting to navigate dense flora, your pace easily fades to just a couple of miles per hour. Plus, it feels like everything is out to eat you. From bugs and flying nasties to jaguar and boars. Heck, even the plants pack a serious punch.

Sit down for a moments respite and the ants will be upon you in no time.

And yet jungle ultras are hugely popular. The races above, and perhaps the most popular of all – The Coastal Challenge in Costa Rica – draw big fields year on year. Perhaps it’s the very nature of the challenge that tempts us ultra runners.

Unless you live in tropical climes with access to rainforests, I believe a jungle ultra is the hardest type of environment to train for. You can replicate, to some degree, the features which make mountain, desert and ‘cold’ ultras hard, but where in the western world are you going to mimic 100% humidity, swamps, and the anticipation that there’s a shed-load of animals around the corner gagging to take a bite out of you?

So, without further ado, how can you prepare for such a challenge? From my personal experience and accounts from many others, here’s my advice…

1. Experience a heat chamber

It’s certainly an expense, and perhaps difficult to arrange, but even just one session in a heat chamber will pay dividends. If for no other reason than it’ll show how vastly you’ll need to adjust your pace expectations compared to normal conditions.

To give you an example, when I run outside, I might sit at 08:00 mins per mile at a heart rate of 130bpm. In a recent heat chamber, I was reduced to 10:30 mins per mile for the same effort. That’s without adding a pack, hills and nasties into the equation.

If you have access to a heat chamber (or even a treadmill in a greenhouse!), then I’d suggest getting three or four sessions in per week, between Week’s three and one prior to arriving in the jungle. Any closer to the race and you’ll be fatigued from the sessions. Go easy, work to heart rate and go as slow as you need to keep effort levels low. This will often mean just walking. That’s fine.

It goes without saying that in a heat chamber, you’ll sweat. Profusely. Drink plenty, replace electrolytes and practice race nutrition.

2. Get your nutrition right

When we think of nutrition, we tend to think of food. And of course, food choices are key in any multi-day ultra, but when it comes to the jungle, caution needs to be taken towards fluid consumption.

Due to a vastly increased sweat rate in humid environments, you’ll lose considerably more electrolytes than usual. Sodium is key, but don’t forget potassium, magnesium and calcium as they’re all crucial if your body is to function optimally.

Have a look at different products on the market. Many these days contain all your need within an energy drink too.

3. Get your feet wet

It goes without saying that your feet will be wet in a jungle. You may cautiously tip-toe around the first few sections of water but it’ll be futile – within 10 minutes your feet will be sodden I assure you!

On half a dozen occasions in training, start your run with wet feet. Just get used to the sensation. When you’re out on the trails, go in search of the puddles and mud and get stuck in. Yes, it’ll hamper your rhythm and slow you down, but that’s exactly what’ll happen in the jungle!

4. Keep your cool

Jungles are humid, if you didn’t know. This is a problem when it comes to nutrition, particularly fluid replacement. You’ll sweat like you never thought possible, but the air is saturated with water vapour, meaning your bodies’ method of cooling – evaporating sweat from the skin – is deemed obsolete.

Be intelligent. Take every opportunity to submerge yourself in water and pour it over your head, neck and on your wrists (where blood passes close to the skin).

Be diligent in ‘checking-in’ on yourself. How am I feeling? Am I working too hard up this hill? Would stopping for a moment reduce my heart rate? Being dialled into how you feel in the here and now will mean you make smarter choices and regulate your body temperature better.

A jungle is the perfect place to use perceived effort as your gauge rather than pace.

5. Neglect hills at your peril

Nobody talks about hills in the jungle, because they’re so focused on the other obstacles. But the hills could be the most overlooked aspect of training when preparing for a hot, sticky race.

I’ve said before that I’m an advocate of hill training even for flat ultras, but in jungles where inclines often exceed the limitations of a treadmill, it’s crucial.

Sure, it’s unlikely you’ll experience the long grinds found in the Alps and Himalayas, but they’re steep, technical and utterly draining.

Crank your treadmill as high as it’ll go and hike up – don’t bother trying to run, you won’t in the race – and get moving.

But don’t let this put you off.

I’d like to finish by saying I hope this article hasn’t put you off running a multi-day jungle ultra. It’s a special, untouched and generally very remote environment that’s a privilege to occupy for a few days.
I just want to convey that they need a little extra thought and preparation to really enjoy and get the best from yourself!

Both races I took part in were brilliant, and The Coastal Challenge – which seems to be the premier jungle ultra out there now – is already tempting me for 2020.


All images are the authors



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Date Range

Global - Virtual


A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for

For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

Endurance - Multi-activity


An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

Suitable for

Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.



Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude)

Suitable for

Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to receipt of a recent medical examination certificate. Purchase of specialist kit is often recommended for these races.



Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat)

Suitable for

Experienced runners who have completed at least 4 ultras in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements.



Increase of up to 1500 metres

Suitable for

Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.



Increase of up to 1000 metres

Suitable for

Runners who have completed at least one ultra in last 6 months or are doing long distance running (>26 miles) regularly, with elevation shown.



Very little change < 500 metres

Suitable for

First ultra event. Runners completing a marathon or doing regular long distance running (>26 miles) in the last 6 months.