Hu­man­i­ty is be­ing sub­ject­ed to ma­jor re­stric­tions in move­ment world­wide in the bat­tle against the spread of pain, suf­fer­ing and death from COVID-19 but, si­mul­ta­ne­ous­ly, the earth’s at­mos­phere is be­ing re­vi­talised. Glob­al ‘lock­downs’ have led to an un­prece­dent­ed re­duc­tion in at­mos­pher­ic Ni­tro­gen Diox­ide due to re­duced emis­sions from fos­sil fu­els. Satel­lite im­agery shows quite clear­ly the pos­i­tive changes oc­cur­ring in earth’s at­mos­phere. But how does this re­late to health, sport and ex­er­cise?

Sci­en­tists have in­di­cat­ed that air pol­lu­tion is more dan­ger­ous than most virus­es. In 2016, it was es­ti­mat­ed that 600,000 chil­dren died world­wide from acute res­pi­ra­to­ry prob­lems caused by breath­ing pol­lut­ed air. In 2018, the World Health Or­gan­i­sa­tion (WHO) re­port­ed that ap­prox­i­mate­ly 1.8 bil­lion chil­dren un­der the age of 15 were breath­ing tox­ic, pol­lut­ed air which could re­duce life. Ac­cord­ing to math­e­mat­i­cal mod­els, in just two months the re­duc­tion in pol­lu­tion that has oc­curred over Chi­na may have saved the lives of 4,000 chil­dren un­der the age of five and 73,000 adults over the age of 70.

Some of the most com­mon air pol­lu­tants in­clude car­bon diox­ide, car­bon monox­ide, hy­dro­car­bons, ni­tro­gen ox­ides, sul­fur ox­ides, par­tic­u­late mat­ters with a di­am­e­ter of less than 10m and ozone. In­di­vid­u­als’ re­spons­es to pol­lu­tion will vary ac­cord­ing to du­ra­tion of ex­po­sure, at­mos­pher­ic con­cen­tra­tion of the chem­i­cals and oth­er health con­di­tions. Per­sons with asth­ma, heart and lung dis­ease for ex­am­ple will ex­pe­ri­ence greater suf­fer­ing in pol­lut­ed en­vi­ron­ments and these per­sons are ad­vised to not ex­er­cise in ar­eas of high pol­lu­tion. For ath­letes, in­hal­ing pol­lut­ed air can ad­verse­ly af­fect health and per­for­mance. The WHO has pub­lished guide­lines re­gard­ing safe lev­els for dif­fer­ent en­vi­ron­men­tal pol­lu­tants and mon­i­tor­ing of these lev­els is be­com­ing more and more im­por­tant in cities where large sport­ing events are held.

At rest, we breathe through our nose. The air is fil­tered thus re­duc­ing the amount of pol­lu­tants en­ter­ing our bod­ies. Dur­ing ex­er­cise, we shift to mouth breath­ing as our body’s de­mand for oxy­gen in­creas­es. Minute ven­ti­la­tion (num­ber of breaths per minute) in­creas­es and the vol­ume of pol­lut­ed air en­ter­ing our lungs al­so in­creas­es. The in­creased air­flow ve­loc­i­ty with ex­er­cise helps to push pol­lu­tants deep­er in­to the res­pi­ra­to­ry tract. A high-per­for­mance ath­lete may breathe up to 20 times more than a reg­u­lar per­son dur­ing train­ing and com­pe­ti­tion. This rep­re­sents a sig­nif­i­cant­ly greater in­take of harm­ful pol­lu­tants. A marathon­er in one race may in­hale and ex­hale about the same vol­ume of air as a seden­tary per­son would over the course of two days.

One study in Iran ex­plor­ing the ef­fects of pol­lu­tion on ex­er­cise per­for­mance at same al­ti­tude but dif­fer­ent lev­els of pol­lu­tion re­port­ed a sig­nif­i­cant de­crease in aer­o­bic ca­pac­i­ty when run­ning in the more pol­lut­ed area. The study al­so showed a greater in­crease in lac­tate lev­els and white blood cell count which may be re­lat­ed to greater tis­sue dam­age oc­cur­ring in the more pol­lut­ed space. Da­ta from the 2014 Bei­jing Olympics point­ed to a neg­a­tive im­pact of race day pol­lu­tion lev­els on per­for­mance of marathon run­ners. Analy­sis of the da­ta sug­gest­ed that the top ten marathon­ers in the world would take five min­utes longer to com­plete their race at the mea­sured pol­lu­tion lev­els.

At the 2018 Asian Games in Jakar­ta, pol­lu­tion lev­els were eight times high­er than the WHO rec­om­mend­ed lim­its. For the men’s 50-kilo­me­tre event, on­ly five ath­letes were able to com­plete the race. The Bahrai­ni ath­lete Rose Chile­mo, who won her event, was 10 min­utes slow­er than her per­son­al best. This per­for­mance is aligned with the da­ta from Bei­jing on the in­verse re­la­tion be­tween pol­lu­tion and sport per­for­mance. Jakar­ta hopes to host the 2032 Olympic Games. One must won­der what ‘Olympic’ plans are be­ing mo­bilised to dra­mat­i­cal­ly re­duce air pol­lu­tion and pro­vide a safe en­vi­ron­ment for ath­letes and spec­ta­tors.

Much con­cern was raised in 2017 dur­ing the FI­FA Un­der-17 World Cup when pol­lu­tion lev­els at com­pe­ti­tion sites in In­dia were six times greater than rec­om­mend­ed WHO lim­its. In 2015, Ger­many had al­ready shown that pol­lu­tion af­fect­ed play­ers’ pro­duc­tiv­i­ty and per­for­mance, es­pe­cial­ly old­er play­ers and those play­ing in po­si­tions with high­er phys­i­cal de­mands. The im­pact ob­served in Ger­many was not very large; how­ev­er, the pol­lu­tion lev­els were al­so with­in the WHO safe lim­its and not at the record­ed lev­els in In­dia in 2017. Re­search ex­plor­ing cy­cling in pol­lut­ed cities has shown that cy­cling for more than 30 to 45 min­utes in the most pol­lut­ed cities in the world may be more detri­men­tal than ben­e­fi­cial to health.

The re­stric­tions im­posed by COVID-19 has shown that be­hav­iour change can rapid­ly have a pos­i­tive im­pact on our en­vi­ron­ment. I urge every­one to use some of the time at home to re­flect on how we could per­ma­nent­ly adopt some of the changes in the post-COVID-19 era and con­tin­ue to pos­i­tive­ly im­pact our en­vi­ron­ment.