Running influencers and the heatwave: when advice can kill

On Instagram, TikTok and YouTube, the vast majority of running accounts are riding the heatwave with advice on running in extreme heat. Meanwhile, people are dying while running.

Thursday 18 June 2026, 11 am. Witnesses find a 30-year-old man unconscious on the athletics track at the Raoul-Dautry stadium in Ermont, Val-d’Oise. Six people begin CPR. A doctor and a nurse from the neighbouring clinic join them. The emergency medical service arrives and confirms his death.

Stories of athletes losing their lives because of their sport have multiplied in recent weeks. At the end of May, during the year’s first heatwave, a man in his fifties died during a 10 km race in Paris’s 20th arrondissement. In Chassieu, Rhône, a 28-year-old woman died from exercise-induced hyperthermia. In Maisons-Alfort, sixteen runners were admitted to hospital in critical condition.

“Sport in extremely hot weather requires absolute vigilance,” the Sports Minister said at the time. That was at the end of May.

Today, 49 departments are under red heatwave alert. Météo-France describes an “exceptional heatwave episode on a national scale, with a severity that could approach that of August 2003”. At the time, the government recorded 15,000 deaths in France over three weeks.

The heatwave, a content factory

On social media, there is very little concern for the lives lost. For influencers, the heatwave is above all a trend. Naturally, running accounts, like other niches, have seized the opportunity to produce content tied to the news.

It is hard to blame them entirely: a running influencer exists by posting regularly about running. Their audience was built on that consistency, and the algorithm rewards it.

They should not be condemned for this approach, particularly when the media also rushes into the arena. Yet informing the public is not something one simply improvises. Journalism is a profession learned both in school and in the field, governed by rules including fact-checking and drawing on experts in a specific subject.

Influencers are not bound by the same ethical standards, which can sometimes lead to excesses. During a heatwave, then, not all influencer advice carries the same value.

The problem is that algorithms reward content that generates the strongest emotions, not factual accuracy. As a result, social media is awash with running influencers offering “advice on running during a heatwave”. Yet scientists, official bodies and doctors say that sport should be avoided as far as possible at the height of a heatwave.

What are running influencers saying?

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Safe Pace is an endurance sports podcast hosted by Hugo Clément, a journalist at France 5. He has 2 million followers on his main Instagram account and 108,000 on the @safepacemedia account. Such visibility calls for a degree of caution when addressing sensitive social issues.

Yet Safe Pace’s publisher released an episode built around this central question: “Episodes of extreme heat are becoming more frequent. But does heat necessarily mean poorer performance? And could it ultimately become a tool for improving?”

Safe Pace examines the topic with a scientist and a trail runner. The podcast itself is fairly useful for anyone who runs regularly. Crucially, it focuses on heat rather than a heatwave. This distinction matters: running can be possible in hot conditions if adjustments are made, whereas during a heatwave it is prohibited.

Unfortunately, the release of the podcast and its heat-related clips coincided with the heatwave. The difference between heat and a heatwave is also rather blurred, potentially leading the public to misinterpret the message. Indeed, the title “Heat: the ultimate method for improving?” can itself be misleading.

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As evidence, on 19 June 2026, when departments were moving to orange alert, three days before a red alert was issued, PurePeople published an article titled “Heatwave: it is possible to keep running”, relying on information from @safepacemedia and supporting it with an Instagram post from the account. The information is accurate in itself, but it once again fails to distinguish between high temperatures and a heatwave.

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U-Trail, France’s leading trail-running reference site, meanwhile published a guide to the “best gadgets for running in very hot weather” during the red alert. RunMotion, Dans la Tête d’un Coureur, i-Run… all published guides on “how to run in a heatwave” in the days before or after the red alert was announced.

All this content assumes the question is “how can you run despite the heat?” rather than “should you run?”. That assumption is precisely the problem.

What do public health authorities say?

It is worth noting because it is unusual: authorities have been clear ever since heatwaves began occurring. Sport should be avoided during a heatwave.

Santé publique France advises people to “limit physical activity as much as possible, even if they are fit and in good health” and to “opt for gentle sporting activities”. The Ministry of Sports has formally called on all sports event organisers, federations, clubs and supervisors to “exercise the greatest vigilance in order to guarantee participants’ safety”.

Above 35-36°C, the surrounding air warms the body rather than cooling it. Any vigorous outdoor physical activity is therefore medically discouraged. Under a red heatwave alert, all intense effort outdoors should be avoided. At the time of writing, the thermometer reads 42°C. Following public health guidance, sport is therefore formally discouraged during a heatwave, at any time of day.

The only conditions in which sport remains possible during a heatwave

The general rule under a red alert is not to undertake physical exertion outdoors, whatever precautions you take.

The only viable way to keep running is on a treadmill in an air-conditioned gym, subject to certain conditions.

The Ministry of Sports and several prefectures explicitly identify “air-conditioned spaces” as an acceptable option. These spaces must meet several requirements:

• The gym must be genuinely air-conditioned (with active air conditioning, ideally between 18 and 22°C); a fan is not enough.
• The activity must remain moderate in intensity: yoga, Pilates, light strength training, stationary cycling, or moderate-paced treadmill running. HIIT and hybrid workouts such as HYROX and CrossFit should therefore be avoided. Swimming is also encouraged, provided the effort remains moderate. Training in an outdoor pool is not recommended.
• Hydration must be increased before, during and after the session, even if you do not feel thirsty.
• Take care when leaving the gym: going from 20°C indoors to 42°C outside carries a risk of thermal shock. Seek out shaded areas.

What do doctors say?

Let us assume that public health authorities are being overly cautious. That is clearly not the case, as the deaths mentioned at the start of this article show, but let us suppose it for the sake of argument. What do doctors say?

Dr Jimmy Mohamed, a GP and health commentator on RTL and France 5, was unequivocal during a previous heatwave:

If you run when it is 35 degrees outside, if you are not used to prolonged exertion, if you are not used to being exposed to such intense heat, you simply risk heatstroke. Do not go running when it is very hot. What is more, air quality is often poor - there is pollution and lots of allergens - so you will feel unwell and, at worst, end up in hospital with severe heatstroke.

This month, he repeated his warnings. He also stressed that the human body needs one to two weeks to adapt to intense heat. It is therefore unable to cope with the sudden onset of a heatwave.

Sports medicine supports these recommendations: exertional heatstroke is an absolute medical emergency and can be fatal if it is not managed properly. For some people, it occurs suddenly, without warning signs.

Professor Pierre Asfar, an intensive care doctor at Angers University Hospital, points out that heatstroke can occur from 25°C when humidity is high and there is no wind. At the time of writing, the thermometer reads 42°C (have we mentioned that already?).

Melon, a summer fruit

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Clearly, all this expert advice is unlikely to reach our beloved running influencers, who appear to be made from the same material as Superman. With summer approaching, their heads seem to have turned into one of France’s most popular seasonal fruits: the melon.

To make their contribution to the debate, though nobody asked them to, they insist that “if you are trained, you can run by adapting”. They then offer their own experience as proof. If they can run and remain in perfect shape, that must surely prove that doctors’ advice does not apply to their divine nature.

A pity that, like Hercules, running’s demigods are still mortal. Sports medicine directly contradicts what they say. Worse still, it explains that they may be the most likely to meet a fatal end, because they are less cautious - or too confident, depending on your view.

Dr Guillaume Gerbaud, a sports doctor at the Chénieux clinic in Limoges, told France 3 Régions that highly trained people are generally at lower baseline risk because they are acclimatised. But “they are the ones who suffer the most heatstroke because, when you feel well, you can push yourself further and not know where your limit lies.”

The High Council for Public Health confirms this: trained athletes “can be affected because they may exceed their capabilities, particularly during a competition.”

Training does not protect you from a heatwave; it creates self-confidence that encourages you to go too far.

The world is not made up of people who run 10 km in 30 minutes

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These influencers also tend to forget that most of their followers are not athletes at their level.

The 200,000 followers of a running account are not 200,000 runners preparing for a marathon. Most of the audience consists of weekend joggers, people returning after an injury, and occasional runners, perhaps running once a week. These profiles follow such accounts to “get motivated”. They are entirely different from a well-trained runner with a programme who knows their body’s warning signs.

Moreover, for this audience, not running for three or four heatwave days has no proven effect on physical fitness. Runners preparing for a competition can also do without running for a few days. According to sports doctors, one week of rest affects neither VO2max nor the cardiovascular capacity of an amateur athlete, even one training for a competition.

By contrast, a single run in 42°C heat can kill. The benefit-risk balance could hardly be clearer. Apparently, though, not to everyone…

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