Science Weekly: heat stroke, sports washing, and the psychology of VAR: the science of the World Cup – podcast

0:00Dr Oliver Gibson:This is The Guardian.

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2:09Dr Oliver Gibson:It's just a week until the first whistle blows at the 2026 World Cup in North America and Mexico. Temperatures are set to be sweltering and a group of scientists is raising the alarm about the impact on players and the quality of the game. Heat is also on FIFA as campaigners call out their fossil fuel sponsorship. Is it another own goal for their climate strategy? And spare a thought for the refs. On top of the climate, they're having to deal with a stepped-up VAR system this year. How will it impact their decisions?

2:53Dr Oliver Gibson:Our Football Weekly colleagues asked us to look into the science of the World Cup. And, well, how could we refuse? From The Guardian, I'm Madeleine Finlay, and this is Science Weekly.

3:11Dr Oliver Gibson:Ian, thank you for joining me at this very special Football Weekly, Science Weekly collab. lab. Now, we're starting with something that might not be too familiar to the English and Scottish teams, at least, playing in the heat. And this is actually something that's also got scientists worried. What are their concerns?

3:31Madeleine Finlay:Well, the predictions are that this could be the hottest World Cup ever, or if not one of the hottest World Cups ever. And that has prompted a group of doctors and scientists to write an open letter to FIFA because they're really concerned about the potential for harm to players and even match officials, the referees. I spoke to Dr Oliver Gibson. He's one of the signatories of this letter, and he's a member of academic staff at Brunel University of London. He studies the impact of heat stress on human performance. And I said to him, what is in this letter? We focused our letter and the research on a metric called wet bulb globe temperature, which encapsulates all of the environmental conditions that the players will experience.

4:15Madeleine Finlay:so it takes into account the air temperature of the environment that the players are playing in but it also acknowledges that heat stress goes beyond just temperature so there's a need to acknowledge the impact of humidity on the players the impact of solar radiation so effectively feeling the sun on your skin and the heat stress that that imparts as well as the potentially helpful cooling effect that comes from airflow and the wind speed that affects players they've worked out in about half a dozen of the cities where these matches are going to be played and we're talking about places like Dallas, Houston, Miami, this wet bulb globe temperature could hit 30 Celsius.

4:52Madeleine Finlay:And that is brutal if you're playing football at the intensity that these elites are going to be playing at. But there's also a concern about what this might mean for the spectacle of the World Cup, for the performance of the players.

5:06Dr Oliver Gibson:Right. So what exactly will these temperatures be doing to the players physically?

5:11Madeleine Finlay:Well, if you think about how the body cools down, obviously it cools down in a bunch of ways, but the main way is through sweating. The body has to dilate all the blood vessels near your skin, and it pumps more blood through those areas. You have the blood near the skin and sweat on your skin. As that evaporates, it takes heat away from the blood, so that cooler blood then gets pumped back to the heart and circulated around the body. If you think about it at the same time, for these footballers, their muscles will be demanding an awful lot of blood as well. so those are in competition and you can get to the point where this cooling just stops working it doesn't do enough and that is when it hits performance and obviously carries these health risks as well and you know the worst case scenario is that you get heat stroke and that can be fatal in that scenario the body temperatures increase quite substantially one maybe two or even three degrees celsius above its resting levels the body also has a what we call a reflex response to increase body temperature.

6:12Madeleine Finlay:So we'll see redistribution of cardiac output or the blood flow away from what the body deems to be non-essential organs in that moment. So for example, the gut, the gastrointestinal tract, the kidneys and the liver, that's not without complications in its own right. So one of the pathways towards heat stroke emanates from the gut. We see the gut become lower in blood flow and people develop this leaky gut syndrome. and with a leaky gut in players what we see is bacteria that should be residing in the gut move into the bloodstream and the body initiates then an inflammatory response to try and resolve those it doesn't have sufficient blood flow to send those bacteria to the liver for clearing in that organ and this inflammation contributes towards what ultimately can be fatal in heat stroke which is multi-organ failure so this is serious stuff and beyond the health risks oliver talked about how heat can impact the game itself.

7:06Madeleine Finlay:We know that football matches played in higher heat stress conditions can seem a little bit more passive. They might be less engaging to the spectator. Players produce less high-speed running. They have the capacity still to sprint as fast, but they choose to sprint less frequently. So we might see in hotter fixtures around 10 % less high-distance running. If you take an average player, it might cover 10 kilometres. that might drop off by around about 10%. The approach to the game might change substantially as well. Although there's some cognitive and decision-making declines that come with heat stress, we know that actually an interesting proxy to that pass accuracy tends to go up when the conditions are hot.

7:44Madeleine Finlay:And that reflects players making more conservative passing decisions to retain possession and avoid the need to do lots of high-speed running to recover the ball. There is a chance, I think the spectator might observe, that the games feel a little bit less thrilling, for want of a better word.

8:00Dr Oliver Gibson:So bearing in mind all of that, what does Oliver want to see happening to mitigate some of these risks?

8:06Madeleine Finlay:So first of all, FIFA have said, look, our top priority is to ensure the health of the players, of the referees, of everybody involved in the World Cup. And they have introduced for this World Cup, each match, regardless of the temperature, is going to have a cooling break in each half. But what the researchers are worried about is that they say that the threshold for bringing in really serious mitigations, and that would be delaying or postponing a match, they say that threshold is too high. And at the moment for the World Cup, that would come in at this wet bulb globe temperature of 32 degrees.

8:40Madeleine Finlay:And these researchers say the recommendation should be 26 degrees. So they are looking for a substantial reduction in that threshold where officials can just say, it's too hot. We have to delay this game. But they also want to have some other changes made too. To spend longer periods than FIFA have currently mandated, they have a three-minute cooling break, which potentially is insufficient, and a six-minute break would allow for more meaningful rehydration and cooling. Potentially, there is a scenario that we haven't really seen in football in the same way we might have seen it in endurance sports like marathon running, for example, where we receive pictures of a player collapsing in the game and there's a suspension of play.

9:19Madeleine Finlay:Perhaps the temperature and the heat stress conditions mean that games are postponed and or delayed in-game for substantial periods of time. All of those are really concerning. Just finally, Maddy, we're now seeing players who've written their own letter in support of this to try and get FIFA to listen. And so hopefully that'll add some weight to it.

9:38Dr Oliver Gibson:And so if there are any coaches or players listening, what should they have been doing to prepare for this heat?

9:46Madeleine Finlay:Well, luckily, Oliver did his PhD on how to acclimatize to heat. So he's a good guy to go to. He says that in a couple of weeks of specific training in hot conditions, the body can learn to cope a lot better with this. And we're talking about training in hot environments, training in sort of heated facilities if you need those, and even bringing in things like saunas and baths into your training program.

10:19Madeleine Finlay:Maddy, behind these soaring temperatures is, of course, the climate crisis. And, you know, there's some irony in the fact that one of FIFA's main sponsorship partners is Aramco, this huge Saudi oil and gas company. Tell me a bit about this.

10:36Dr Oliver Gibson:Yeah. So FIFA signed this global partnership with Aramco, this huge fossil fuel company. This does cover the World Cup as well. And Aramco are actually the sponsors of Houston, host city. So fans are going to be seeing Aramco's name everywhere. Now, you might argue that this is a pretty clear example of sports washing. So that's when companies sponsor athletes or events to kind of improve their reputation. Bearing in mind, Ian, all that you've been telling me about in terms of the heat, I think there are lots of fans who are going to be not very impressed with this. The environmental impact of these sorts of events, very often you see it from flights.

11:24Dr Oliver Gibson:You might see like in Qatar when there were stadiums being built. But the impact of advertising is much more subtle. But there is an impact. I mean, they wouldn't do it if there wasn't. Now, I chatted to Peter Crisp. He's a campaigner at Fossil Free Football. It's a grassroots organisation of fans. And he said that seeing all the advertising of polluting companies made him feel like football was on the wrong side of things. And that actually the beautiful game or the people in charge of it really needed to start taking this seriously.

12:00Madeleine Finlay:So what are FIFA's commitments to tackling emissions in football?

12:05Dr Oliver Gibson:FIFA have committed to the global goals of the 2015 Paris Climate Agreement. So they've pledged to achieve a 50 % reduction in their carbon emissions by 2030. And they've also pledged that they're going to reach net zero by 2040. They have a climate strategy. And one of the things that this climate strategy is supposed to do is to protect FIFA's tournament games. And that's from things like heat, from flooding, from extreme events. So it could even be things like smoke from wildfires. But Ian, their choice of sponsors aside, there are a few things that are going to make it hard for FIFA to argue that this World Cup is in line with that strategy.

12:48Dr Oliver Gibson:And that's because they've massively increased the number of teams in this World Cup. So it's gone from 32 in Qatar to 48. So that's many more games being played in the stadiums across three countries, the US, Canada and Mexico.

13:04Madeleine Finlay:So what kind of impact will this World Cup have on the environment?

13:09Dr Oliver Gibson:It's going to be pretty significant. So the organisation Scientists for Global Responsibility, they've calculated that this World Cup is likely to generate more than 9 million tonnes of carbon dioxide equivalent, making it the most polluting World Cup ever. And they've also calculated that this is about the same as 6.5 average British cars driving for an entire year. So that really puts it into some context. And most of those emissions, the majority really are going to come from the flights. So that's fans flying in from around the world and then flying between matches as well, you know, flying between the three different countries.

13:52Dr Oliver Gibson:And look, if you want a big global event like this, some of that is obviously totally inescapable. But if fans in the Northern Hemisphere want to keep these summer tournaments, organisations like FIFA are going to have to start bringing down these carbon emissions because the summer is becoming less and less viable to host these tournaments. I mean, us in the Northern Hemisphere, we love going to beer gardens to watch the games, you know, around the games, going to parks, having a barbecue. and if the heat is really kind of repressive, that becomes less and less enjoyable. But also for the players, like you've said, for the staff, for the fans in the countries where this is being hosted, when there is this extreme heat, it's not safe.

14:38Dr Oliver Gibson:And sure, you can move the games to further in the evening and you can introduce these hydration breaks, but at some point it just isn't going to be enough.

14:48Madeleine Finlay:Bearing in mind, this is likely to be an extremely hot World Cup. Do you think this is going to kickstart that conversation in football again?

14:57Dr Oliver Gibson:This is obviously what campaigners like Peter Crisp are hoping for. I'm sure he wishes that they didn't have to have these conversations because he pointed out to me that, you know, there are billions of football fans around the world. And so there are billions of them who really care about the climate crisis and want to see strong policies put in place to protect the game that they love. And I do wonder if the fans are going to struggle this year in the heat themselves, or if there are other extreme weather events that begin to really disrupt games. This is going to be on the agenda. And Ian, the next World Cup is in 2030.

15:40Dr Oliver Gibson:So we can imagine what the temperatures might be like then. And the hosts are Morocco, Spain and Portugal. So this problem is certainly not going anywhere.

15:54Dr Oliver Gibson:Coming up, the psychological impact of VAR for referees and fans.

16:17Ian Sample:When you're booking a hotel, do you use Hotels.com? Actually, you're probably just going to say, I don't know. Producer Joel does it. I don't know. Producer Joel does it. Well, I think you should give it a try for yourself. Obviously, it's a massive summer of soccer and loads of our listeners will be traveling to watch the tournament and needing to book somewhere great to stay. So it's good to know that when you're a Hotels.com member, you can save up to 20 % on hundreds of thousands of hotels. Plus, you earn rewards on every stay. So each trip you take helps pay for your future trips. Just use those rewards like cash.

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17:13Dr Oliver Gibson:ian did you know that studies have shown that heat makes people more aggressive and angry i for one can attest to that but there's something else that is potentially going to get fans blood boiling at this world cup and that is of course var and recently there was a study on var that you've been looking into. What's this about?

17:38Madeleine Finlay:This all came about when a guy called Dr. Daniel Walker, he's a researcher in psychology of sport at the University of Bradford. He was watching a football match with his dad when the referee was called over to do an on-field review where they go and look at the screen in full view of everyone. His dad goes, this decision is going to be overturned. Daniel was like, yeah, I bet it is. It was. It got Daniel thinking about, is there anything that happens in the fact that the game stopped and the referee is told to go and look at this evidence again because BAR has decided that he may have missed something, are you kind of psychologically primed to think, yeah, I got that call wrong?

18:18Madeleine Finlay:So Daniel looked at more than 1 ,500 matches in the English Premier League from the last few seasons, so from 2021 onwards, and they found about 250 occasions where the ref had been called over to do one of these on-field reviews. And when they looked at how often those overturned the referee's original decision, it was 95 % of the time. So clearly, if you're sitting there watching a match and VAR says, ref, come and have a look, the chances are that that decision will be overturned.