How Much Thinner is The Air at 7000ft Then at Sea Level

A good rule of thumb is that there is one percent less Oxygen available per 100 metres of ascent. You were around about 6500ft, 2000m higher, so that's about 20% thinner.

Uhhhhh....actually, the percentage of oxygen in the atmosphere doesn't change with altitude.

The pressure actually changes.

At 7000ft, the oxygen in the atmosphere is still ~21%.

read his post again. available oxygen. he did not say percentage of oxygen.

Check out this link. Some pretty interesting stuff about altitude and how it affects running.

http://www.letsrun.com/forum/flat_read.php?board=1&id=1373219&thread=1373219

7000 times thinner.

I'm not sure about air thickness, but I've heard the 10% adjustment thrown around for 6,000 feet. Where a run at 6,000 ft is equal to 10% longer at sea level. I don't think there's any science behind it, just a rule of thunmb.

So your 45 miles will equal roughly 50 miles at sea level.

"Than"

Late Breaking News From NASA!!!!

One mile is equal to....ONE MILE!!!!!

Some interesting comments here. Two additional points of interest might be (1) hard to compare cycling and running in this matter because the speed of cycling is so great that the benefits of lower air resistance outweighs the drop in VO2max and the (relative) slower running speeds only benefit about half as much as is the loss in VO2max. For swimmers, the drop in air resistance is sort of a non factor, however the less dense altitude air can move more easily in and out of the lungs and the cost of ventilation may drop a little at altitude (hard to prove). (2) Compared to sea level, it costs a little less at altitude to run at any given speed, so you might say the cost of a mile at altitude is actually more equal to running less than a mile at SL, which would mean you can actually run more miles at altitude for the same energy expenditure. If you feel more fatigued from fewer miles at altitude, it therefore must be that you are stressing yourself at a higher (relativre) intensity during your altitude runs, not because the altitude miles are more costly.

The above calculators are good: I have always heard / read that at 15,000 feet its 25% less 02 but at the summit of Everest (29,000 feet) you are down to 75 % less than at sea level ... There are tables you can find to show this.

Really it depends on the distance and time you are running: Altitude has been shown to have a cumulative effect. A single mile run at 10,000 feet may only be a couple percent slower than a mile at zero feet ... While a marathon at 10,000 feet will be a lot slower (like 10%).

juicy miler wrote:

So i just got back from utah where i was doing all my runs between 7000 and 8000 feet. I live at and normanly train at around 400-600 feet above sea level. I def noticed a difference, but exactly how much thinner is the air at 7000ft and how does it affect my running.

For instance if the thinness of the air at 7000ft is 50% of the air at 400 feet, then would a 10 mile run at 400 be equal to a 5 mile run at 7000.

anyone got any facts or charts on the air thinness at different altitudes? Im curious because i usually am around 55 miles per week at 400 feet but was only able to run about 45 miles per week at 7000 ft due to fatigue.

One place to get an idea about it is to look in the NCAA T&F handbook, it has tables for equivalent qualifying times at altitude.

Where were you running in Utah at 7000ft? IWere you in the mountains because most cities near the wasatch front are around 4500ft? Park City maybe?

i'm from sea level, and i have spent several years now training at altitude for extended periods - i.e. 4 months at altitude, 1 month at sea level. altitude slows your longer workouts, and it is generally a bad idea to race high unless you've lived high for a while. a lot of people i know qualify to nationals with altitude adjustments even though they've lived high their entire life. these people RARELY run their altitude equivalents at sea level. but, sea level people racing high often run faster than their altitude equivalents when returning to sea level. just something i've noticed.

if you raced at 7000+ feet on a track, you're looking at about:

9-10 seconds difference for a mile

50 seconds difference for a 5k

2 minutes difference for a 10k

as it has been said before, the effect is cumulative - the longer you race the more it slows you.

i have no idea how much hills would slow you. everyone i knew used the 10% rule as stated before.

after years of training at high elevation i've come to believe that altitude training is over-hyped. to be honest, training at altitude will make a very small difference. but, moving to altitude may be the commitment you need to make your lifestyle more running orientated (better diet, more mileage, etc.). i know that this thread isn't necessarily about this, but i would like to state that you shouldn't just move to altitude and expect to get fast. rather, you'll be better off just training harder and smarter where you are. if you need a little extra advantage, like a second in the 1500, then altitude training is worth a go. i think it is over-rated though.

I've noticed extreme advantages when training at altitude for several months.

The couple of times I've done that my 5k times have dropped 20 seconds at least releative to the exact same training I had been doing at sea level prior.

Here's the chart I use for hiking, biking, and running:

(Note: all these percentages are atmospheric pressure compared to sea-level.)

0 100%

1,000 96%

2,000 92%

3,000 88%

4,000 85%

5,000 81%

6,000 78%

7,000 75%

8,000 72%

9,000 69%

10,000 66%

11,000 64%

12,000 61%

13,000 59%

14,000 56%

15,000 54%

16,000 52%

17,000 50%

18,000 48%

19,000 46%

20,000 44%

I find the biggest difference is running uphill at altitude. I've never calculated to what degree I slow down going uphill at altitude (compared to sea-level), but I have little doubt that in terms of percentage, altitude affects me far more going uphill than running on level ground or downhill.

Also, I personally think when you temporarily run at altitude, the best equivalent to make is to run based on time, not distance. If a 20-miler takes you 2:30 at sea-level, then just run 2:30 at altitude, even though that might only end up being 16 miles instead... unless you're trying to train for a race at altitude (like Leadville or Pikes Peak).

why do people say that the air is "thinner" at high altitudes? the word doesn't make sense when you think about it. definitely less dense, but not thinner.

"Than"

get ugly wrote:

why do people say that the air is "thinner" at high altitudes? the word doesn't make sense when you think about it. definitely less dense, but not thinner.

Words have more than one meaning. See #3b.

"thin"

ADJECTIVE:

thin·ner, thin·nest

1a. Relatively small in extent from one surface to the opposite, usually in the smallest solid dimension: a thin book.

1b. Not great in diameter or cross section; fine: thin wire.

2. Lean or slender in form, build, or stature.

3a. Not dense or concentrated; sparse: the thin vegetation of the plateau.

3b. More rarefied than normal: thin air.

4. Flowing with relative ease; not viscous: a thin oil.

Watery: thin soup.

5. Sparsely supplied or provided; scanty: a thin menu; thin trading.

6. Lacking force or substance; flimsy: a thin attempt.

7. Lacking resonance or fullness; tinny: The piano had a thin sound.

8. Lacking radiance or intensity: thin light.

9. Not having enough photographic density or contrast to make satisfactory prints. Used of a negative.