Summer athletics in Australia means twilight meets, 6 am sessions and the odd 38-degree afternoon. Heat slows everyone down and, at the extreme, it's dangerous. This post gives you the competition rules, a sweat rate calculator, a plan for getting used to the heat, and what to do when someone's in trouble.
This is general guidance, not medical advice. The tools work from the numbers you enter. Athletes with heart or kidney conditions, a recent illness or medications that affect sweating should get advice from their doctor before training in heat.
Look for
- Confusion, odd behaviour or slurred speech
- Stumbling, loss of coordination or collapse
- Very hot skin after hard exercise in the heat
Do this
- Stop the activity and call 000.
- Cool the whole body immediately, ideally by putting the athlete in cold or iced water. If you can't, douse them with cold water and use ice towels while fanning.
- Keep cooling until help arrives. How long the body stays very hot drives the outcome, so cooling on site comes before transport.
One page with these steps, the competition bands and the cooling options. Stick it in the kit bag or on the clubhouse wall.
Why it matters
Across 1.79 million marathon finishes, air temperature was the biggest weather factor on performance at every level, not just at the back. At the 2007 Chicago Marathon (25°C), 30.7% of starters didn't finish.
Getting used to the heat starts working within 3 to 5 days and is mostly done by 10 to 14. Heat guidelines name it as a way to lower the risk and to race better when it's hot.
Sports Medicine Australia's 2025 heat guidelines rate the risk for your sport from local temperature, humidity, sun and wind, rather than temperature alone.
Competition Heat Check
Australian Athletics competitions run on air temperature measured trackside, in the shade, every hour. Enter the reading to see what the Australian Athletics Weather Policy requires.
1Trackside temperature
Measure with an accurate thermometer, out of direct sunlight, and recheck every 60 minutes.
Training Heat Risk
For training, use the Sports Medicine Australia Sports Heat Tool. Pick your location and sport and it combines the local forecast (temperature, humidity, sun and wind) with how hard and how covered-up your sport is, then gives you a rating for now and the next seven days.
Drink more than usual and switch to lighter, more breathable clothing.
Add or lengthen rest breaks, for example at least 15 minutes of rest for every 45 minutes of training.
Use active cooling during breaks, or before and during the session if it runs continuously.
Consider calling it off. If the session has started, stop as soon as you can, get everyone into shade or air conditioning and cool them.
Sweat Rate Calculator
Sweat rates range from about half a litre to more than two litres an hour between athletes, so a one-size drinking rule doesn't work. Weigh before and after a session and you'll know how much this athlete actually loses.
How to use it
- Go to the toilet, then weigh in wearing minimal clothing, on a scale that reads to 0.1 kg.
- Train as normal. Keep track of how much the athlete drinks (weigh or measure the bottle) and any toilet stops.
- Towel dry and weigh again on the same scale in the same clothing.
- Repeat in different conditions. A hot track session and a mild easy run give very different numbers.
1Body mass
2During the session
Sweat rate
For a similar session next time
Your saved tests
Save each test with a note on the conditions. They stay on this device only, so you can build up a picture over the summer.
How this is worked out
Sweat lost = mass before minus mass after, plus fluid drunk, minus urine passed, counting 1 kg as 1 litre (Baker 2016). The "drink during" figure is the sweat rate minus the loss that would keep the athlete just under 2% of starting mass over the same session length, the threshold the American College of Sports Medicine uses (Sawka et al. 2007). The pre-session figure follows Sports Medicine Australia's 2025 advice.
The method has known errors. Forgetting urine can overstate sweat loss by up to a third, and sweat trapped in clothing understates it. Sweat rate also changes by about 5 to 7% from day to day, so look for patterns over several sessions.
Getting Used to the Heat
The body gets better at handling heat quickly: lower heart rate, lower core temperature and earlier sweating. Pick the date of a hot race or a trip to warmer conditions and work back.
1Your target
The plan counts back from here.
Downloads a calendar file with the start date, check-in and race day. It opens in Google, Apple or Outlook calendars.
14 days out. Begin daily sessions in the heat (or the hot bath option below).
After 3 to 5 days, heart rate and core temperature start to come down.
By 10 to 14 days most of the benefit is in. Ease the volume as you taper.
Run as normal, then sit in a hot bath (about 40°C) for up to 40 minutes straight after, for six days in a row. In trained runners this lowered core temperature and heart rate during exercise in the heat, and the effect was still there two weeks later. Stop if you feel dizzy or unwell.
If training is interrupted, heat adaptation fades gradually, at roughly 2.5% a day for heart rate and core temperature, and it comes back 8 to 12 times faster than it took to build. A missed week isn't a restart.
Your 14 days
Staying Cool
These are the cooling options Sports Medicine Australia recommends, and when each one works best.
| Method | Before | Between efforts | After |
|---|---|---|---|
| Cold drinks and slushiesLower core temperature before you start. Less effective once the session is underway. | |||
| Pre-coolingAn ice vest or sitting in cold water before a hot race lowers the starting temperature. | |||
| Water on the skinDousing with a sponge or spray bottle helps sweat evaporate. Misting fans work even better. | |||
| Arms or feet in cold waterA tub of cold water at the end of the track is cheap and quick between reps or events. | |||
| Ice towelsDamp towels with crushed ice, or ice packs, around the neck between efforts. |
Who needs extra care
Sports Medicine Australia lists people over 65 (especially if unfit), anyone with heart or kidney disease, anyone recently sick with a fever, people on medications that impair sweating, and anyone who has just arrived from a cold climate. The evidence isn't clear on whether children are at higher risk than adults, so treat juniors with the same care and keep an eye on them.
One more from the guidelines: paracetamol doesn't lower body temperature during exercise, so don't use it to try to manage heat.
Notes and References
Check the heat tool before you plan the session, not after.
Weigh in and out a few times each summer.
If someone's confused in the heat, cool first.
What this research can't tell you
Sweat rates measured in one session only apply to similar conditions, and the bathroom-scale method has real errors. Most heat adaptation research used trained men in laboratories, and the marathon data comes from overseas big-city races, not Australian track meets. The Australian Athletics competition bands use air temperature alone, while the Sports Heat Tool also accounts for humidity, sun and wind, so on humid days the two can point in different directions. Follow the competition policy at meets and use the Sports Heat Tool for training.
This is general advice based on research and published guidelines. It doesn't replace medical advice or your club's own policies.
References
- Australian Athletics (2026) Australian Athletics Weather Policy.
- Baker, L.B. (2016) Sweat testing methodology in the field: challenges and best practices. Sports Science Exchange, 29(161).
- Daanen, H.A.M., Racinais, S. and Périard, J.D. (2018) Heat acclimation decay and re-induction: a systematic review and meta-analysis. Sports Medicine, 48(2), pp.409–430.
- El Helou, N., Tafflet, M., Berthelot, G., Tolaini, J., Marc, A., Guillaume, M., Hausswirth, C. and Toussaint, J.-F. (2012) Impact of environmental parameters on marathon running performance. PLoS One, 7(5), e37407.
- Racinais, S., Alonso, J.M., Coutts, A.J. et al. (2015) Consensus recommendations on training and competing in the heat. British Journal of Sports Medicine, 49(18), pp.1164–1173.
- Roberts, W.O., Armstrong, L.E., Sawka, M.N., Yeargin, S.W., Heled, Y. and O'Connor, F.G. (2021) ACSM expert consensus statement on exertional heat illness: recognition, management, and return to activity. Current Sports Medicine Reports, 20(9), pp.470–484.
- Sawka, M.N., Burke, L.M., Eichner, E.R., Maughan, R.J., Montain, S.J. and Stachenfeld, N.S. (2007) American College of Sports Medicine position stand: exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), pp.377–390.
- Tartarini, F., Smallcombe, J.W., Lynch, G.P., Cross, T.J., Broderick, C. and Jay, O. (2025) The Sports Medicine Australia extreme heat risk and response guidelines and web tool. Journal of Science and Medicine in Sport, 28(9), pp.690–699.
- Wickham, K.A., Wallace, P.J. and Cheung, S.S. (2021) Sex differences in the physiological adaptations to heat acclimation: a state-of-the-art review. European Journal of Applied Physiology.
- Zurawlew, M.J., Mee, J.A. and Walsh, N.P. (2019) Post-exercise hot water immersion elicits heat acclimation adaptations that are retained for at least two weeks. Frontiers in Physiology, 10, 1080.
Figures and citations checked against the published sources, October 2026.