Training in the heat: how to keep “cool” when things get “heated”

Recently we’ve experienced significantly hot temperatures and every year is getting hotter.

This makes it hard to train, particularly as winter sports commence pre-season fitness work, let alone the summer sports which are competing in the sweltering conditions.

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The temptation might be to stay inside, relax or maybe go for a swim.

But what if I told you that training in the heat (when done sensibly) may be the best thing you could do?


Training in hot temperatures

Researchers have found that training in the heat can increase an athlete’s blood volume, leading to improved fitness, reduce their core temperature and blood lactate levels, resulting in them being able to go harder for longer.

Further-more some studies have demonstrated heat training to improve muscle strength and improved performances in cooler weather as well.

It is now generally accepted that training in the heat is more beneficial than altitude training.

Training/performing in the heat has its own risks due to the extra stress it places on the body.

If you don’t take steps to prepare for the hot weather when training or competing you risk a very poor performance as well as heat stroke.


Keeping cool when training in the heat

To keep cool your body sends blood to circulate through your skin, leaving less blood to supply your muscles.

This causes your heart rate to increase to push the limited blood around the body faster.

When the humidity is also high, your body is unable to cool itself efficiently via evaporating sweat causing further stress to the system and elevating your body temperature even higher.

If you exercise too hard without proper preparation or adaptation you may develop confusion, irritability, headache, heart rhythm problems, dizziness, fainting, nausea, vomiting, visual problems and fatigue.

These are signs of heat stress or heat illness and you should seek immediate medical attention to prevent brain damage, organ failure and eventual death from untreated heat illness.

Heat-related illnesses are largely preventable with some basic precautions, however; if you have any concerns about medications, pre-existing medical conditions and/or exercising during summer - you should seek a medical review with your Doctor.


How to avoid illness from training in the heat

The best prevention strategy to avoid heat illness is to remain hydrated.

This will help maintain blood volume and your body’s ability to sweat and remove heat from the system.

Waiting until you are thirsty is too late and instead you should commence hydrating prior to exercise with 400-600mls of water/sports drink and then continue to consume smaller amounts regularly throughout training/competition.

According to the AIS, being insufficiently hydrated impairs the body's ability to regulate heat resulting in increased body temperature and an elevated heart rate.

This means you will tire quicker and feel like you’ve worked harder than in cooler temperatures.

Your ability to make decisions and concentrate deteriorates and stomach discomfort often occurs due to a slower stomach processing speed.

The good news is that by drinking regularly during exercise you can prevent the negative effects of dehydration on concentration, heart rate, body temperature and performance.


How much fluid to drink when training in the heat

How much fluid you need in total will vary from person to person and situation to situation.

To ensure you rehydrate completely after training/exercise you can weigh yourself before and after.

Each kg lost (despite your best efforts to stay hydrated) equates to needing at least another litre of fluid to be consumed.

In total you should aim to drink 150% of any fluid deficit in the 4-6 hours after exercise to account for any delayed/future losses from further sweat and urination.

A good way to know that you’re hydrating properly is by checking the colour of your urine.

If it’s pale yellow (think lemonade), you’re well hydrated.

If it’s darker (heading toward the colour of apple juice), drink more.

Sports Drinks

Research shows that fluid intake is enhanced when beverages are cool (~15 °C), flavoured and contain sodium (salt).

A lot of research is out there in regards to every detail of sports drinks even down to the flavour profile, all in an effort to encourage fluid intake during performance.

Sports drinks in Australia are sold to a strict criteria ensuring fairly uniform levels of Carbohydrate, Salt and Sugar which in the right amounts all help to maintain hydration.

The carbohydrate included helps to refuel the body and current research recommends its consumption to benefit performance in any high intensity activity lasting longer than 60 mins.

Water is better than nothing but it does not stimulate further fluid intake nor contain the necessary salts to replace those lost in sweat.

Similarly cordial and juice generally don’t contain the right mix of carbohydrates and salts and generally lead to slower stomach processing times, gastrointestinal upset and overall lower levels of hydration.

Choose something with 4-8% carbohydrate, 10-20 mmol/L sodium, reasonably priced, tastes good and in a bottle that makes consumption/storage/staying cool easy.

Most importantly, buy something you will drink.



  • 6% carbs, 18mmol/L sodium


  • 7.6% carbs, 12mmol/L sodium


  • 6% carbs, 14mmol/L sodium


  • 7.5% carbs, 14mmol/L sodium
training in the heat sports drinks


Practical Tips – Putting it all into practice:

Consider more drinks breaks, regular interchange/substitution during trial games and shorter interval training sessions to combat the effects of higher temperatures.

Common sense should always apply and if you aren’t prepared or have concerns about the pending weather conditions talk to your coaches and club ahead of time about your options.

Restrict warm up to a minimum as it will take less time in hot weather to get the muscles warm and blood circulating.

Take the extra time available to instead “pre-cool” and “pre-hydrate” before starting to train/play with icy cold drinks, applying cool water and ice to the trunk of the body and sit in the shade preferably with a fan to promote evaporation and heat loss from the body prior to commencing the game.

Plan ahead of training and matches to ensure you have a cold drink available especially on field for planned drinks breaks periods.

Half filling, then freezing, the drink bottle overnight before filling the rest with cold water before heading to the game is one simple strategy you can use to have a cold drink available.

Wear a hat/cap if you prefer but remember a significant amount of heat is lost via the head and a cap gathering sweat will impede this natural radiator cooling effect so ensure that at drinks breaks and half time it is removed and “cooled” with cold water to allow the head to radiate heat as much as able.

Don’t forget sunscreen – I’m sure we’ve all felt how “hot” burnt skin feels even the next day.

Due to the damage to the skin, sweating and natural heat loss mechanisms become disrupted. Slip, slop and slap!

Wear light colours if able as these absorb less heat than dark colours (eg black) and even better, choose loose fitting clothes to promote air flow around the body over tight compression garments eg skins.

Use the time available at half time to cool your body as much as possible again and rehydrate.

Strip down and jump in the shower with cold water only, fan your body if able and apply cold water over your head and body, apply ice to the armpits, neck and groin, seek shade and cold water to rehydrate.

Avoid caffeine, alcohol and sugary drinks like coca-cola etc as these will further dehydrate you and be detrimental to your performance/recovery.

Plan ahead and pack snacks that contain water and can be frozen/cooled for an added bonus (eg watermelon, oranges, grapes, blueberries).

Preparation is key but the best way to enhance your performance in the heat is to start training earlier in summer, embrace the heat and acclimatise in a safe manner.

Summer will pass quickly and it’ll be a cold, wet, windy night in July when you’ll wish it was summer all over again.

Enjoy it whilst it lasts.

As always if you want help or advice with training or injury management please don’t hesitate to get in contact and I’ll see what we can do to help.

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Author: James Cleal (Physiotherapist (APAM, BPhysio, Level 2 Sports Therapist)