Why do we get sick more often in winter, even though we sit almost all the time in a warm room?

Let’s dis­cuss one of the impor­tant advan­tages of air humid­i­fi­ca­tion — reduc­ing the num­ber of colds. Accord­ing to var­i­ous sources, prop­er air humid­i­fi­ca­tion in win­ter can reduce the inci­dence of dis­eases by 1.5–2 times. In addi­tion, the sever­i­ty of symp­toms and the num­ber of days spent in a state of ill­ness are sig­nif­i­cant­ly reduced.

Let’s fig­ure it out.

As you know, air is char­ac­ter­ized by absolute and rel­a­tive humid­i­ty. Absolute is sim­ply how much evap­o­rat­ed water is in the air (for exam­ple, grams of this water in a cubic meter of air), and rel­a­tive is how much less such water is com­pared to how much air could hold in itself. The pos­si­bil­i­ties of air to hold water in itself are not unlim­it­ed and have a very spe­cif­ic lim­it, and this lim­it depends on tem­per­a­ture. The low­er the tem­per­a­ture, the low­er (and much low­er!) The abil­i­ty of air to retain evap­o­rat­ed water.

It turns out that if the air is heat­ed, then the absolute humid­i­ty will not change, since how much water was in the air, so much will remain. But the abil­i­ty to absorb water will great­ly increase and, con­se­quent­ly, the rel­a­tive humid­i­ty will decrease, which, as we already know, is the pro­por­tion of water in the air com­pared to the max­i­mum pos­si­ble. This is where the insid­i­ous­ness is hid­den, water does not seem to dis­ap­pear from the air when heat­ed, and the rel­a­tive humid­i­ty drops sharply.

But why is rel­a­tive humid­i­ty impor­tant at all? Yes, because we feel it. It is the rel­a­tive humid­i­ty that deter­mines the rate of evap­o­ra­tion of mois­ture from the skin, from the mucous mem­branes, from the hair. And a sharp (many times!) increase in the rate of evap­o­ra­tion plays a key role in all man­i­fes­ta­tions of “low humid­i­ty”.

Now let’s see what hap­pens when we breathe in air? In the air­ways, it must be moist­ened, oth­er­wise the lungs will not be able to work prop­er­ly. In cold weath­er out­side, the air has a low absolute humid­i­ty, since in a cold state it can­not hold enough water. When inhaled, such air heats up, this is nat­ur­al, and its rel­a­tive humid­i­ty drops sharply, as we already know.

For­tu­nate­ly, the body is per­fect­ly trained to deal with such a sit­u­a­tion. To increase the amount of water in the inhaled cold air, the sur­faces of the res­pi­ra­to­ry tract active­ly begin to secrete spu­tum. The nose “flows” in the cold, this is an absolute­ly nor­mal reac­tion of a healthy body, the lungs are pro­tect­ed.

But in a warm room in win­ter, the sit­u­a­tion is dif­fer­ent. The air, heat­ing up in the room, nev­er­the­less retains a low “street” mois­ture con­tent, there is nowhere for it to absorb water. As a result, the room has low rel­a­tive humid­i­ty, usu­al­ly 10–20% (with a norm of 35–60%), and the evap­o­ra­tion rate has increased sev­er­al times com­pared to the norm. It would seem that there are no prob­lems, because in the cold our body copes with addi­tion­al mois­ture when inhaled. But no! Reflex “wet­ting” of the mucous mem­branes works at low tem­per­a­tures, and we inhale already heat­ed air!

From the point of view of evo­lu­tion, man very recent­ly began to live in arti­fi­cial­ly heat­ed air, so the body is not adapt­ed to such a sit­u­a­tion. From his point of view, if the air is warm, then it is warm out­side, and if it is warm out­side, then the rel­a­tive humid­i­ty is not low.

There­fore, when inhal­ing arti­fi­cial­ly heat­ed air, with­out adding mois­ture (while dur­ing the nat­ur­al warm­ing of the weath­er out­side, the air picks up mois­ture), the sur­faces of the res­pi­ra­to­ry tract begin to dry out, the full-fledged self-humid­i­fi­ca­tion mech­a­nism does not turn on. But the mucosa is also mucilagi­nous, it feels nor­mal only when it is wet. And in a dried one, it ceas­es to resist pathogens well and can­not effec­tive­ly get rid of them, since this would require spu­tum, which is no longer in suf­fi­cient quan­ti­ty on the sur­face. All! Hel­lo virus­es, hel­lo bac­te­ria.

It turns out that the human body is sim­ply not ready for a sit­u­a­tion where the inhaled air is warm, but has such a low humid­i­ty. There is no such thing in nature, even in the desert. And the main rea­son for the increase in the num­ber of colds in win­ter is not the frosty air out­side, to which a healthy body adapts per­fect­ly to peri­od­ic stay, but a long stay in con­di­tions of low humid­i­ty and warm rooms.

Expo­sure to dry indoor air has a cumu­la­tive effect, per­ma­nent expo­sure to such con­di­tions caus­es harm. Try­ing to “heal” the room with ven­ti­la­tion only wors­ens the sit­u­a­tion, as the humid­i­ty is fur­ther reduced due to the abun­dant sup­ply of low-mois­ture out­door air.

There­fore, it is impor­tant that as much of the day as pos­si­ble, both adults and chil­dren would be in evo­lu­tion­ary habit­u­al con­di­tions for the body. That is, either in the fresh air, where the tem­per­a­ture and absolute humid­i­ty are con­sis­tent with each oth­er, or in a warm room, but with humid­i­fi­ca­tion work­ing, so that there is no dis­crep­an­cy between humid­i­ty and tem­per­a­ture.

Unfor­tu­nate­ly, in Rus­sia the sit­u­a­tion with air humid­i­ty is espe­cial­ly unfor­tu­nate, but the point here is already in cul­tur­al dif­fer­ences. We are accus­tomed to stok­ing heat and walk­ing at home in win­ter in light clothes. Dur­ing the cold sea­son, a 5‑degree rise in room tem­per­a­ture means a decrease in rel­a­tive humid­i­ty by about 10%. The air in our homes is usu­al­ly dri­er than in coun­tries accus­tomed to sav­ing on heat­ing.

The con­clu­sion is sim­ple. Nei­ther good ven­ti­la­tion nor air­ing will fix the sit­u­a­tion. To main­tain a healthy indoor cli­mate in win­ter, it is absolute­ly essen­tial to humid­i­fy the air, and you need to make sure that the humid­i­fi­ca­tion sys­tem is real­ly up to the task. Well, walk more!

Buh­ler-AHS Rus­sia

Source: Buh­ler-AHS Rus­sia