Running vs. cycling in the heat

Sadlebred

I'm genuinely curious....Why would runners not do a marathon if it's 80 degrees?

As a cyclist, I race in all sorts of weather. 110 degree temperature index (99 degree air temp+humidity)--check. 25 degrees and snow--check. 50 and 30 mph wind gusts that took out most of the course tape--check. Pouring rain and 40 degrees--check. Cyclists will ride and race in any and all weather as long as it's not dangerous such as lightening, tornados, etc. There are plenty of cycling races--road and mountain biking--held in the middle of the summer when temps are well into the 90s. The same goes for triathlons, and they run. Tens of thousands of riders and charity cyclists do century rides in the summer every year.

I'm not knocking anyone or anything. I just wonder why it wouldn't be the same for runners. Why would you not run/race a marathon when it's warm or hot?

al320

Becuase running is harder, duh. J/k I have no idea. But i am a mess when i run in the heat, i dehydrate super fast, and uust feel sluggish and overall crappy. A hot day will add a good minute or so to mympace (more if its over 80 or so). Humidity makes it worse too, even if its not that hot. Im sure there is a reason, but i only cycle indoors. I whine when my spin instructor doesnt turn on the fan, so id probably be the same in the heat on a bike as i am on foot in the heat.

steph81

I don't think it's just the running in the heat is the challenge. The bigger obstacle to me would be training for something under certain conditions and then being hit with a major weather change. I didn't read the actual article about Boston but its definitely been a drastic change in weather in the northeast. I personally would still try to finish the race under any condition. 

Joenali

I think it's easier to fuel on a bike and you don't get AS hot. Running is higher impact, you sweat more and your body depleats it's electrolytes faster. That's why in a triathlon you fuel as much as you can on the bike, especially if it's hot.

kat.in.the.hat

I think for Boston specifically it's because most runners coming aren't used to running in such temps; it's very warm for that race.

But they hold races in super hot conditions all the time, lots of ultras in Arizona, New Mexico, etc and there's even some "hot as hell" marathons here in Texas during the summer.

And the IM in Kona is known for the crazy hot temps, so people who race that have forewarning and can train appropriately.

Honestly though, from what little I know of pro cycling and from what I read on twitter (which makes me an expert, obvs) I think pro cyclists train under the most extreme conditions from race to race.

BelieveInStephens

DH bikes and runs and is forever complaining ofthe heat when he runs. He tends to think that going faster on the bike makes it less brutal, like the wind evaporates the sweat, cools him down better...

Susie Derkins

You get a LOT hotter running in the heat than you do cycling in the exact same weather.  Even if you're exerting yourself at the same level (e.g. same heart rate), it's a totally different ball game re: cooling yourself.

When you're cycling at, e.g., 20 mph, you're generating your own "wind" and have air moving over you at that kind of velocity.  Less if you're riding with the wind, more if against, but you get the idea.  You don't get that benefit when you're running, since you're moving much slower.  Sweat doesn't evaporate as well without that air moving over you, so you overheat quicker.

Sadlebred

Susie Derkins:

When you're cycling at, e.g., 20 mph, you're generating your own "wind" and have air moving over you at that kind of velocity.  Less if you're riding with the wind, more if against, but you get the idea.  You don't get that benefit when you're running, since you're moving much slower.  Sweat doesn't evaporate as well without that air moving over you, so you overheat quicker.

This makes total sense! 

gumiberg

boston also starts later in the day, some people start at noon.  the sun is high. i have noticed that its not heat that is hard, its direct sunlight.  i think 90 degree cloudy weather is pretty nice running weather. but mid-day sunny 90 degree weather?  it's not comfortable.

also, since boston attracts people from all over, a lot of people are not acclimated to warmer weather like that. if you have not trained in heat, you are not going to do well in heat.  and you wont be used to the effects (ie higher heartrate, dehydration, etc).  people work so hard to get to Boston, you cant expect them to take it easy. my friends are okay with the hot temps, obviously but i can understand why someone from a colder climate would not feel okay about it.  i'd be so bummed though to train and defer.  

moshi's paw

Susie Derkins:

You get a LOT hotter running in the heat than you do cycling in the exact same weather.  Even if you're exerting yourself at the same level (e.g. same heart rate), it's a totally different ball game re: cooling yourself.

When you're cycling at, e.g., 20 mph, you're generating your own "wind" and have air moving over you at that kind of velocity.  Less if you're riding with the wind, more if against, but you get the idea.  You don't get that benefit when you're running, since you're moving much slower.  Sweat doesn't evaporate as well without that air moving over you, so you overheat quicker.

I was going to say this as well. Cycling creates your own "wind chill" and your body temperature doesn't rise as fast.  If you're running in the same weather conditions (ie, hot), your body temps can rise to like 103*F because it can't cool off as much as when you're on a bike.