air density and breathing

[02GF74]

In winter when the air is cold, like outside now , the air becomes denser hence there is more oxygen in any given volume.

If you drive your car, you should notice a slight increase in power to say on a hot summer's day.

Anyways, I try to go running at lunchtime twice a week and pretty sure my breathing is a bit easier despite the rest of me being most unhappy about the cold temperatures. On the other side of the coin, on a hot summer's day, I think I have the opposite effect struggling a bit to get air.

Now there is another factor which is that I am generally much fitter in summer since the amout of exercise I do diminishes when it starts to get cold and wet out side. My running times are therefore much faster and it may be due to therei being less resistance due to less dense air. Also the cold temperatures aren't very conducive to running faster so I don;t try as hard as in summer.

So is the air density a real effect or am I just fooling myself?

What would be good to try is to run in summer but have a supply of cold air to check out this theory.

 

[cheadle hulme]

My Fabia VRS is noticeably quicker in cold weather.
I, on the other hand am noticeably slower as my muscles do not seem able to use the extra oxygen. Legs feel like they're filled with cement at the moment.

 

[jimboalee]

Oxygen density is calculated ( or easier read straight off a graph ) from Atm p, amb air t and RH ( relative humidity ).

In an engine test environment, Atm p is measured with a piezo quartz transducer, amb air t is measured with a platinum resistance thermometer and RH is measured with a wet/dry bulb electronic transducer ( Vaisala ).

The calc is complex, and I've forgotton it, as I last calibrated an engine test cell in 2002.

Air kg/m3 is approx 1.21 at sea level at 20 C, 1000 mb and 50% RH.
O2 density varies by 20.5 - 20.8 % extremes at sea level.

The effect in O2 density is less than the 'ram' effect of keeping your mouth open to force air into your lungs.

 

[yello]

And here was me thinking it was t'other way around. That is, harder work when the air is colder. I seem to recall reading somewhere (could have been on this very forum... so a load of old wallop of cod) that the body burnt energy warming the oxygen!

 

[jimboalee]

Yello, it is true. The body uses energy heating inhaled air. It is, however, included in Basal Metabolic Rate.

 

[Kestevan]

As an Asthma sufferer I always seem to find I get short of breath much quicker when its a bit parky outside.

Although this is somewhat offset by the lack of pollen and general "smog" you can sometimes experience in summer.

 

[RedBike]

I don't know about summer /winter but I always used to find that I was slightly quicker when time-trialling just after a good rain shower.

The rain always used to make things feel fresher / It felt like there was more oxygen in the air.

Then again it could be because my tyres rolled quicker on a damp road.

 

[gratts]

I think you're fooling yourself

 

[jimboalee]

Asthma sufferers will get short breathed sooner in the cold. Like everything else, the bronchial system contracts on contact with cold air.

As far as I can remember, higher humididy decreases O2 density. Not a lot and I think, like me, the resurgence of power after a rain shower is psycological.

Fooling ourselves !

 

[Twenty Inch]

This would only hold true if your body used ALL the oxygen in a given lungful of air. However, you only use about 17% of the oxygen you breathe in. This is why mouth-to-mouth resuscitation works.

You're kidding yourself.

 

[Twenty Inch]

I don't know about summer /winter but I always used to find that I was slightly quicker when time-trialling just after a good rain shower.
The rain always used to make things feel fresher / It felt like there was more oxygen in the air.

Then again it could be because my tyres rolled quicker on a damp road.

Joe Beer has put this down to elevated levels of ozone in the air.

 

[jimboalee]

+1
The amount of oxygen taken up per breath is pretty dreadful really. Its about a seventh ( 14% ) of the available oxygen in the air.
20.6 % is reduced to around 17.5%.

Remedy for hyperventilating during a panic attack is breathing the same air from a paper bag. The air can be inhaled about nine or ten times before the oxygen is consumed. Then the patient regains their normal blood O2 level.

To avoid any missunderstanding, if the human being could utilise the O2 which represents 17% of the Air per breath, theoretically they could be able to generate 6 times the power in the muscles. If this were true, you would be able to put 1 kW into the rear tyre easily, which would get you along at 35 mph without distress, and 50 mph on a sprint.

If only

 

[Quoth]

If your muscles feel like lead during this cold weather, it's because they are more viscous and it takes more "effort" to get them moving. A bit like what happens when you put jelly in the fridge...

 

[numbnuts]

Having emphysema I also find that I’m more breathless in colder weather

 

[DaveP]

As a part-time diver, I have often wondered what the effects of breathing Nitrox (oxygen enriched “air” i.e. 32% oxygen) would be on a typical ride.

I will never do it as the weight of the gear plus looking like a complete numpty is so off putting….