When FIFA announced that Qatar would host the 2022 World Cup there was surprise and concern from many quarters because of the country’s summer temperatures. And now it looks as though many organisations are backing a move from summer to winter for the tournament because of those concerns.
Qatar certainly has an extreme climate. Jutting out into the Persian Gulf it is an arid peduncle covered largely in sand and gravel. Average temperatures for July are over 35oC. That’s the average day and night-time temperature across the entire month. At 5am, the coolest time of night, temperatures can still be above 30oC and relative humidity can be 100%. The maximum daytime temperature in the shade for July is over 41oC. In the shade!
Now as students of the NEBOSH Diploma Unit B will know, the human body is well equipped to keep core temperature at 37oC. That’s the temperature at which our biochemistry works best and the body has complex thermoregulatory mechanisms to keep it that way. Foremost amongst these mechanisms is sweating as a way of loosing heat. Blood supply to the skin is increased by vaso-dilation, sweat glands extract water and salts from the blood and this liquid is excreted onto the surface of the skin. As the water changes state from a liquid to a vapour it takes energy (the “latent heat of evaporation / vaporisation” for all of you physics nerds out there) from the skin in the form of heat. This heat loss cools the skin, which in turn cools the blood and so cooler blood can be returned to the core to collect more heat that is then returned to the skin, etc, etc. In this way a cooling cycle is established where heat from the core is transported to the surface and then away by sweating.
Of course heat is lost from the surface of the body by radiation and conduction as well. But radiation and conduction only work when the temperature of the surrounding air is less than the temperature of the body. Once air temperature reach 35oC heat won’t radiate away and sweating becomes the only effective cooling mechanism.
To be effective as a cooling mechanism sweating only works if the sweat can evaporate. If sweat can’t evaporate then all that happens is that you loose water and salts from your bloodstream and your clothes get wet. Not pleasant. And also, of course rather dangerous, since you will be dehydrating; your blood gets thicker and more difficult to pump around the body. And you are loosing valuable electrolytes that are essential for normal body functioning. End result, heat stress leading to heat stroke. Heat stroke is where the core temperature has started to rise above 37oC. Organ damage can occur at core temperatures over 41.7oC. Once the thermoregulatory control centres of the brain have started to warm up, they stop working effectively, so core temperature spirals out of control very rapidly; leading to convulsions, coma, death. That sort of thing.
Relative humidity is a measure of the amount of water vapour in the air expressed as a percentage of the maximum possible water vapour content of air at that same temperature. So if relative humidity is 100% then it means that it is not possible to get any more water vapour into that air. It is saturated.
So if ambient temperatures are above 35oC and relative humidity is 100% then your only heat loss mechanism, sweating, won’t work effectively. You can sweat but all it does is make you wet, it does not cool you down. If the night-time temperature is 30oC and RH is 100% that’s one very uncomfortable nights sleep.
Give me aircon!
The Wet Bulb Globe Temperature (WBGT) Index is one way of assessing the thermal environment by measuring three of the parameters of that environment to give an indication of heat stress. For an outdoor environment the three parameters measured are the wet bulb temperature, dry bulb temperature and globe temperature. These are measured using three slightly different thermometers. WBGT is then calculated as 0.7 wet + 0.2 globe + 0.1 dry and is expressed in oC.
This temperature can then be used to give an indication of heat stress for people doing different levels of work (see ISO 7243). For example, a non-acclimatised person resting (i.e. doing no appreciable work) will experience heat stress if the WBGT goes above 32 oC. A fit and acclimatised person doing hard physical work will experience heat stress if the WBGT is 25 oC or over. By heat stress what we mean is an inability to keep core temperature down to 37 oC. So core temperature will rise above 37 oC and there will be nothing that the person can physiologically do to stop that from happening. They must stop work and/or move to a different thermal environment to cool down.
WBGT is also used by many authorities (e.g. ACGIH) as a way of predicting the work: rest routine that will avoid heat stress. For example if WBGT is 26oC and the worker is doing moderate work then a work: rest routine of 75% work: 25% rest per hour should not be exceeded. If WBGT temperature is 32 oC then even light work should be broken up with rest on a ration 25% work: 75% rest per hour to avoid heat stress. If WBGT goes over 38 oC then the hourly capacity for moderate work for an acclimatised worker drops to zero.
The mean WBGT in the shade for Qatar in July is 30oC. The maximum is over 32oC. These are as measured during day and night over the full month of July. In the shade. Just to put those numbers into context, the comparative mean and max for UK in July are 15 oC and 18 oC respectively.
For a no-acclimatised person doing no work, heat stress starts at a WBGT of 32oC. Do light work (such as walking) and heat stress starts at a WBGT of 29oC. Something a tad more strenuous (such as a little light jogging or jumping up and down) and the figure drops to 26oC.
The recommended work: rest regime for a WBGT of 30oC is 50% work: 50% rest if you are doing moderate work and 25% work: 75% rest if you are doing heavy work.
Whichever way you look at it being out of an air-conditioned environment in Qatar in the summer is going to be challenging. Doing any kind of physical activity; very challenging if not actually dangerous.
Now many of the organisations that have been lobbying FIFA for a change from summer to winter months are perhaps concerned about the players. But the players can live in air conditioned environments for much of their time in Qatar. They can train in temperature regulated facilities. The stadiums being built will have significant cooling technology built into them that may even allow fairly “comfortable” playing environments. Though exactly how comfortable, time will tell. The players are all fit as fleas, as the phrase has it. They will be under constant medical surveillance. And they will be fully acclimatised.
What about the fans? Who will not have had time to acclimatise but will plunge straight into 30oC minimum temperature and 100% relative humidity. Many of them will not be fit as fleas. Many of them will be drinking, some of them will have heart conditions, liver and kidney disease and other underlying health conditions that will jeopardise their ability to thermo regulate.
Well its personal choice isn’t it. Nobody is making them go. “Volenti” I hear all of you NEBOSH Diploma Unit A law students out there shout.
What about the workforce who have to build theses stadiums? Who have to work in the desert heat and build the air-conditioned accommodation and technologically wonderful stadiums. Qatar has found itself at the centre of slave-labour allegations in a recent Guardian report. The report makes pretty grim reading. Overseas workers are trapped in gruelling working conditions without basic welfare facilities and without the ability to leave. Fatalities are running at almost one a day (and the true figures will probably be impossible to discover) and those that do not die in workplace accidents are dying of cardiac arrest. Probably brought on by extreme heat stress.
To borrow a quote from Bill Shankly ‘Some people believe football is a matter of life and death, I can assure you it is much, much more important than that.’
What a beautiful game.
Jim Phelpstead BSc, PhD, CMIOSH
Working in health and safety for 18 years Jim is a long-standing RRC Associate Tutor, who loves the great outdoors.