OldsCOOL

We are having rather high humidity for our area and with the combined 90+deg heat it makes for a hot day. So when the evening approached and humidity was still in the 50+% range I hit the hills for a short, very intense routine ride on my favorite local route.

It was the last hour of sun and temps were slowly dropping....88deg at ride time. Now here is the kicker. The first hill is a local favorite on Strava. My ride tonight jumped me 2 places and I shaved 25sec off my PR. I was rockin' the entire hill, seemed like it went real fast and it did.

Never once did I feel oxygen debt or gasping for air like in times past. Tonight was something entirely different.

Does the extra humidity give a boost of oxygen, enough to make this kind of difference in respiration levels? I know in engine performance you can gain extra oxygen molecules and better performance in humid weather if every thing else is ok.

Any physiologists onboard with any helpful info?

Captain Blight

Good question. In aviation circles, humidity is a pain as it reduces air density. Maybe your increased performance was due to less drag?

SJX426 

Was this ride just a part of an everyday habit or was there a break of a day or two before?

OldsCOOL

I'm not completely ruling out a good recovery on the ride, it's been 10days since running this hill and route. Last day of intense riding was Monday (a flat 16mi "interval"....no kicking back) and the previous Saturday I rode a fast 30....both of these rides were PR runs as have all of the rides I've taken in the last 3wks. What makes me wonder on this hill is just how much of a jump in time reduction there was. 25sec on this 1.4 is no easy feat.

Here is the link to the ride last night.....

https://app.strava.com/rides/12599791

I'm #7 after moving up from #9. The last run I made at this hill was a 7:59.

OldsCOOL

This could very well be a function of "heat acclimation" of the body on performance dynamics:

https://www.ncbi.nlm.nih.gov/pubmed/20724560

fas2c

In my experience high heat and humidity levels decrease ones performance. I cannot consume enough water to keep myself hydrated when it is hot (+95F and +80% humidity, 80 is considered low here btw) to begin with. Also, the air is so heavy it feels like breathing through a wet washcloth. It makes it tough to keep up a high endurance activity for any amount of time.

ColonelJLloyd 

+1 Add to that air filled with allergens. Eff the Ohio Valley.

Lewis_Moon

What's humidity?
Around here I'm up at 4AM and on the bike by 5 just to outrun the sun. Humidity takes second place to being fried.
When I was racing, I'd use my commute as a training ride. On summer afternoons I'd head home with the outside temps sometimes over 110. With the low humidity I could dedicate a bottle to keeping my head and quads doused and feel "comfortable". During monsoon season, (yes, we have a monsoon) I can really tell if the humidity goes way up. Did I mention "way up" means over 20%? It's like a kick in the solar plexis.
When I ran cross country in school, the coach always moved me up in the line up if it was raining. I set all my PRs in the rain. I have no idea why that worked.

Lenton58 

I have always just assumed that higher humidity challenged oxygen intake. In Sendai, the humidity rarely gets below 60% at any time of the year. The heat of the summer is attended with humidity in the high 90's. On some days the sun can be shining, and moisture will condense right out of the air. This is the only Asian country I have ever been in, so I can't compare, but on days like this even moving around is difficult, let alone climbing in stand-ups on the inner ring — GASP! I know that there are worse paces — even in Japan. But I don't wanna know about them. I think humidity makes breathing harder. But, I am no physiologist.

rootboy 

I think higher humidity makes breathing harder too. I miss the dry Great Basin.

OldsCOOL

This I have found true on the rides above 30mi at my stage of riding. I've done 81mi in 90deg humidity and just gave in from the heat. You cant cool down with the higher relative humidity.

Keep in mind that the ride I'm referring to in the OP is a hillclimb course with few flats. I finished the 14mi in 46min last night. I'm still not sure where that huge improvement came from but I sure aint looking that gift-horse in the mouth.

AZORCH

Instead of riding, I'm sitting here on the couch looking out the window at the thermometer, which currently registers 107 degrees. Humidity is so thick you could cut it with a knife. That is definitely decreasing my performance at the moment.

RobbieTunes

Just a good day!

old's'cool

I'd have to look it up on the psychrometric tables to give a quantitative assessment, but qualitatively speaking, increasing temperature has a "double whammy" effect on oxygen density, since the oxygen density is decreased not only by the loss of air density due to temperature, but also by increased displacement of air with water vapour, at constant relative humidity. To say nothing about the other physiological effects of high temperature and/or high humidity.

Roadfrog

88 degrees and 50% humidity is considered a very good day to ride where I live. I suspect your state of rest and acclimatization had a lot to do with it. Us southern riders might be able to take the heat but not the cold where you live near the Arctic Circle.

KvltBryce

I'm with you on that one. Not sure if it's hotter in Gold Canyon than in Tucson, but I've shifted the majority of my riding to night rides to avoid a heat stroke ahah.
Summer nights here are hard to beat though.

ColonelJLloyd 

I did a short club ride at 5p today. The temp was 104 when we set out, but the humidity was only 50% or so. Still, it wasn't possible to drink enough water. When we stopped to refill bottles I got chills. But, a bottle dumped on my back did the trick.