Written by Simon Austin – May 26, 2022
WHEN monitoring our website analytics over the last few months, one article has regularly featured among the best-read and we struggled to work out why.
It’s this one, from December 2017, and is about the prevalence of exercise-induced asthma among elite footballers. Which, at first glance, does not seem hugely topical.
However, further investigation has revealed the reason why it’s being read so often: because social media is currently full of conspiracy theories about the use of asthma inhalers by Liverpool’s players and people obviously wanted to find out more.
The genesis of the rumors is a September 2020 article that quotes a “source close to the club” (always a red flag) who “reveals” that 22 member’s of Liverpool’s 35-man first-team squad are asthmatic. The treatment for the condition is then described as being “substances to enhance and support performance.”
So we decided to provide some evidence-based analysis and spoke to the country leading expert on asthma in elite athletes, Professor John Dickinson, the Head of the Exercise Respiratory Clinic at the University of Kent, about the issue.
Dickinson has worked with Premier League clubs, the England national team and Olympic athletes in both diagnosing and treating asthma, as well as publishing numerous research papers on the topic. Our Q&A with him is below:
Q. Any basis to this figure of 22 of 35 Liverpool players being asthmatic?
Professor John Dickinson: The rumor I saw was 63%, as you say. There is no official data out there on this. A club is not going to pin the number of players that are using various medications on a board somewhere. I think that’s what this is – a rumor. Where it came from, who knows?
Back in 2010/11 I did screen the club’s first-team squad and we published a paper on it. That was back in the days when Dr Peter Brukner was Head of Sports Medicine and Science at Liverpool and Zafar Iqbal was first-team doctor.
About 25% of the players had exercise-induced asthma. A lot of clubs wouldn’t have let us publish that data, but they saw it as, ‘We’re doing best practice here and we want to tell everyone about it.’
Q. If the incidence of asthma was so high, would that raise concerns?
It’s a higher figure than we’ve published from elite football in the past. In our previous study that you wrote about (in 2017), we found that 27.8% of footballers within our sample had exercise-induced asthma, so almost one in three. The prevalence within the general population is somewhere between 9 and 12%, so roughly 1 in 10.
This figure of 63% wouldn’t necessarily be unreasonable though. If it was true – and I have no way of knowing whether it is or not – my response would be that the club are being proactive in identifying those athletes who do have asthma.
The reason for the higher prevalence of asthma in elite footballers is two-fold: firstly the high ventilation rates, because they’re training and playing at high intensity; and the fact that they are often exposing their airways to cold dry air. These two factors predispose them to increased risk of the condition.
In other elite sports the incidence is actually much higher. In swimming, for example, we’ve reported it to be about 70%. This is largely because the chlorine in the water produces a gas called trichloramine that can trigger an inflammatory response in athletes’ airways.
Q. What treatment is prescribed for asthmatic players?
There is no known cure for asthma, so you are never going to fully get rid of it. Most footballers have it on a mild to moderate basis which in the general population would only require the use of an inhaler two to three times a year.
However, elite footballers are exerting themselves to much higher ventilation rates, which can trigger an inflammatory process in the airway. This, in turn, triggers a muscle contrition around the airway, which is what we know as asthma.
The blue inhaler is salbutamol and it relieves the muscle constriction, but it does not really touch the inflammation. If an athlete solely relied on that, the inflammation would still be there and their bodies would get used to the salbutamol, so they would have to take more of it as time went on.
So the idea around therapy is that you prevent it occurring rather than dealing with it once you get the airway constriction. The medication athletes should be using most regularly is an inhaled corticosteroid, the brown inhaler, which might be used in combination with a Beta2-agonist, which is the purple inhaler.
They will need to take the brown or purple inhaler every morning and evening regardless of how they are feeling and this will dampen down the inflammatory process in their airways and reduce the chance of experiencing asthma.
If you’re playing a match and are going to exert yourself and might get symptomatic then you could still take your salbutamol inhaler about 20 minutes before going out and that should do you for four hours, so you should be fully protected for the game.
Saying that I’ve not seen any players taking a puff before running out on the pitch or running over to the side to have a puff either. If they were doing that I’d be a little bit worried because it would mean they weren’t controlling their asthma properly.
Q. The big question: Are asthma inhalers performance enhancing?
Within therapeutic doses, no. From an anti-doping point of view an athlete is not allowed to use more than six puffs of the blue salbutamol inhaler during a 12-hour period.
However, there have been some studies with endurance athletes in which they’ve taken 80 puffs of a blue inhaler in a day and have then done time trials to exhaustion. The findings were that there was no change in performance and no change in oxygen kinetics, which is how fast you can take oxygen in.
The only thing they really saw was an elevated heart rate, which is actually detrimental to performance, because for a given workload you’re having to work harder. There’s also a fair chance you would get the shakes and perhaps heart palpitations too.
You can also get salbutamol in a pill, which is totally banned for athletes. This is because a much larger content of salbutamol is going to hit your muscles if you take it orally rather than inhaling it. With the pill, it goes into your stomach, through your intestines and gets picked up by your blood and goes around the body.
If you inhale it, it gets into your lungs but the transfer to your blood is minimal. The pill does not get prescribed very often at all – basically only if you are in hospital and are having a very severe asthmatic episode.
With the brown inhaler, athletes can use that as much as they like within anti-doping rules, but it’s usually only prescribed for two to four doses per day. With the purple inhaler, two to four puffs per day is usually also prescribed, which is again within the anti-doping rules.
There is also an oral form of the brown inhaler, called prednisolone, and this is the area where there’s a bit of a gray area. Within two weeks of competition, athletes are not allowed to use it. But they are allowed to use it outside of that window.
For footballers, it is not likely to be used, because they play so often, but they might get a therapeutic use exemptions (TUEs) with a short-term window in which they can use it; or a retrospective one, if they have asthma and it flares up really badly and they need prednisolone to dampen down the inflammation.
If that was the case then the athlete would probably get pulled from completion because the asthma was so bad. But there are potentially a few cases in which the athlete’s asthma might flare up a day or two before competition and they ask for oral prednisolone to reduce the inflammation. Then they can potentially use it during competition and it’s an anti-inflammatory, which would dampen down inflammation across the whole body and aid recovery.
My argument would be that if they get a TUE for prednisolone they should not really be competing at the highest end of elite competition, because if they’re having that flare-up their lungs probably aren’t healthy enough to compete.
Q. How do you find out if a player is asthmatic?
We objectively look at the function of the airways. We take a measure of how well an athlete can breathe in and out in terms of the flow of air and we take a measure of inflammation inside their airways as well. We do that at rest, but that’s not enough, because for most footballers their lung function will look normal then.
So what we do – which the players do not particularly like – is try and trigger an asthma response. The most common test is a hyperventilation challenge. The player sits down and breathes a cold, dry gas at an intensity that replicates high-intensity training they do for six minutes.
We measure lung function after that. If it stays the same, it shows that they do not have a form of asthma, but if it drops off – so the amount of air they can breathe out in one second – by more than 10%, that indicates they have some form of asthma.
The greater the drop, the greater the severity of the asthma. Then We can then work out what form of therapy they need. We do a follow-up test six weeks after they’ve started the inhaler to judge the effectiveness. Lung function should not drop off as much by then.
If it’s not quite working, we can modify the inhalers and techniques used.
Q. Why is it important to diagnose exercise-induced asthma in players?
Not using an inhaler when you have asthma yet continuing to exercise at high intensity can lead to airway remodeling – a permanent thickening of the airway wall and a mildly chronically obstructed airway. It does not happen in everybody but it increases the susceptibility.
They are also more likely to pick up coughs and colds, because asthma is an inflammation issue, which makes them more susceptible. We have also found that asthmatic players who are not using inhalers see a drop in aerobic performance.
This means they can not train as well as everyone else and get the full adaptations from the training. You can make more out of those training sessions, with the repeated sprints and high intensity, if you have a healthy airway.
Q. Is football good at diagnosing and treating asthmatic players?
A club would generally call someone like me, a University service, to do the screening; or perhaps the English Institute of Sport. We haven’t been getting many calls! A lot of the time the clubs might be doing the in-house screening, but they won’t have the same specialized tests.
If you look at the expertise within most clubs it’s not respiratory and it’s not necessarily at the top of their priority list. What does a typical medical day look like? The majority of the time it’s functional testing, peak power and some body composition, because they’re the key things related to football performance.
Things like asthma they will only really be picked up on when the player is signing for the club. It’s not like the doctors won’t know how to manage asthma, but without the initial objective test they won’t know how severe it is and whether medication is being optimized.
I wouldn’t say screening of athletes in elite football has moved on too much from that article we did in 2017 to be honest. It relies on medics at the club making screening a priority.
The cost of screening a group is not that much – about £ 150 per player if groups of 10 or more are tested – but for a club it’s often more a question of time and practicalities. It takes about an hour for each player to do the test.
So if you’re trying to get through a squad of 30, you have to write the day off, or else do one or two a day. Saying that, I have been into clubs and done 15 players in four hours. You can overlap them a bit and we tend to bring a team of four people. We have embedded our team within pre-season medical days before.
The other thing I’ve found is that the players do not like to do the test, because they do not like the hyperventilation. We do the same test with Olympic athletes and they do put up with it better! If you do not do it in pre-season it’s not happening.
It’s not about making money for us, as a University, it’s about improving screening and education so that diagnosis and then treatment of asthma can get better.
- TGG contacted Liverpool for a response to this article but they did not wish to comment.