Sign up

Supported by the Heat-Aware Sports Foundation

Know how hot you really run.

During a ThermoClinic you measure your own core temperature on a training run. You see live what exertion does to your body, and you learn how to recognise, treat and prevent heat illness.

Sign up · €45 What to expect

Max 15 participants per clinic. Also on location for running groups and clubs.

Core temperature · 45 min run 39.1°C
40° 39° 38° 37° 0 min finish > 40° = risk rises sharply
Your temperature lags behind your effort: it often keeps rising even after the finish. You'll see this on your own data during the clinic.
40°Ccore temperature above which the risk of heatstroke rises sharply
5–10 kmrun at your own pace, with a CORE sensor
15participants maximum per clinic
€45per participant, group rate on request

The clinic

From theory to your own data in three steps

Not a dry presentation, but hands-on experience. You learn how thermoregulation works, measure your core temperature on a real run, and then analyse your own results.

1
Presentation · approx. 45-60 min

Understand your body

How does your body regulate its temperature? Why do you perform worse in the heat? You learn to recognise, treat and prevent heat illness, with insights from research and elite sport.

2
Run · 5–10 km

Measure your core temperature

You're given a CORE sensor and a sports watch for a run at your own pace. You see live how quickly your core temperature climbs towards 39°C.

3
Analysis · reviewed together

Read your own data

We look at your temperature curve together. You see how your temperature lags behind your heart rate and even keeps rising after the run. That's how you translate the theory to your own races.

Participants with CORE sensor during the run Reviewing the temperature data together

What you learn

Perform more safely and better in the heat

Understand thermoregulation

What happens in your body during exertion and heat? Knowledge from research, including the Physiology department at Radboudumc.

Cooling strategies and acclimatisation

Practical techniques from elite sport to start cooler, stay cooler and recover faster.

Recognise and treat heat illness

The signs of heat exhaustion and heatstroke, in yourself and in others, and what to do immediately.

Race smarter in warm weather

Match your pace, ambition and drinking to the conditions. Heat illness can occur from a feels-like temperature of just 15°C.

Who it's for

For anyone who runs or coaches runners

Heatstroke often strikes precisely the fit, well-trained and motivated athletes. Awareness matters for every runner.

Individual runners

Sign up for a scheduled clinic. Ideal preparation for summer races such as the Dam tot Damloop or an autumn marathon.

€45 per participant

Running groups and clubs

From five participants we come to your club. Location, date and time by arrangement, including weekdays during the day or in the evening.

Group rate on request

Event organisers

Prepare your participants for hot editions and strengthen your safety policy. See also hittebewustsporten.nl for advice for organisations.

Tailored, by arrangement

Scheduled clinics

Upcoming ThermoClinics

The dates come live from our calendar. Don't see your date? Email us and we'll plan one by arrangement, including weekdays during the day or in the evening.

Loading calendar…

Maximum 15 participants per clinic. Once full, it's full.

Why this exists

Heatstroke is life-threatening. And preventable.

In 2014 Arthur Fonville, 24, died of heatstroke at the finish of the Dam tot Damloop. His father Joost then started ThermoClinics with one goal: to prevent others from going through this.

In 2025 Joost founded the Heat-Aware Sports Foundation (Stichting Hittebewust Sporten). Its goal: to make athletes, organisers and healthcare professionals aware of the risks of exercising in the heat. Every year in the Netherlands, athletes end up in hospital with heat illness, while with good preparation this is almost always preventable.

Read more about the foundation →

Core temperature > 40°C During heatstroke the central nervous system becomes disrupted: confusion, slurred speech, neurological symptoms. Vital organs sustain damage.
Not only in hot weather Because of the intensity and duration of the effort, heat illness can already develop from a feels-like temperature of 15°C.
Fit athletes especially Contrary to common belief, heatstroke doesn't mainly strike untrained or older athletes. The typical victim is young, fit and motivated.

“I knew hot weather was tough. But only when I watched my own core temperature climb towards 39 degrees did I really get it.”

ThermoClinic participant

Done a clinic yourself? Share your experience

Practical

Everything at a glance

  • Cost€45 per individual participant
  • GroupsFrom 5 participants, your own clinic at a group rate
  • Group sizeMaximum 15 participants per clinic
  • Run5 to 10 km, at your own pace
  • EquipmentCORE sensor and sports watch provided on loan
  • SchedulingWeekdays during the day or in the evening also possible