Dreadmill or Run Outside in the Heat?

In theory I'll always prefer to be outside, but usually when it's over 90, I simply can't go very far.  Call me weak, but the heat just sucks the ever loving life out of me.  I still try it though, cause I can't go too far on a treadmill either.

So I guess my real answer is neither...if it's over 85 and sunny or humid, I have no expectations of having a decent long-ish run.  Luckily, I'm usually able to go in the early AM.

That's a pretty good test. 

I would normally do a long run today.  But I know that that the heat, combined with the humidity, will make it slower and still likely result in a tougher recovery than normal.  Since I don't have a race coming up, I will probably just do a short run instead--unless it feels much better out than I expect.  (Running indoors isn't an easy option for me this evening.)  If I had a race and might expect similar conditions, then I'd probably adjust my pacing as best I could and go do it.

In Central Texas we have been dealing with 100+ degrees for almost 40 days. I tried to run on Monday and thought I was going to die. Since then I have been to the gym for the dreadmill and bike. 

I normally run/bike early around 5AM but lately I've been lazy...so at least the gym is a nice option. 

Hopefully I can get out of this funk I'm in and start getting my butt out of bed again :-/

I am training for IM Louisville so it's in my best interest to get out there in the heat.
Like many areas of the country, mine is experiencing this "heat dome" sitting on top of us. It is oppressive, to say the least.

My best advice, if you are going to be out there, is bring a handheld water bottle and plan a route so you can re-fill often. Rest when you need to and monitor your RPE or heartrate. Slow down as necessary.

To the OP - can you run in the evening after the sun goes down? I did this Sunday night - had to remember my headlamp and to plan my route so it hit fast food restaurants/gas stations that would still be open past 11 p.m. for my water re-fills.

If I can get a run in in the morning (7-8 am), I'll do it. I did 4 miles outside this morning at 7 and it was around 80 with 90% humidity, but it actually went pretty well. For me, the sun beating down on me is what kills me. I tried running 10 miles last week around 10 am and I couldn't do it. I made it 7, but they were 7 craptastic, slow, awful, torturous miles. Couldn't do a morning run the other day, and at 7 pm the heat index was still in the triple digits, so I hit the dreadmill at the gym. I was able to run way faster than I have been, due to some nice a/c and being able to actually breathe, so it was much more productive than wilting in the heat.

Heat and/or humidity has never forced me to run on the dreadmill.  I just slow down and lower my expectations and listen to my body.

OTOH, -10 or colder in the winter usually finds me inside.  :-)

depends on where you are.  at 100 degrees and 75% humidity (or higher) treadmill, because race or no race, why would you want to subject yourself to that kind of torture.

100 degrees and 15% humidity, then outside.

100 is hot but it's not unbearable.  It's the humidity that kills you.

What's a treadmill? 

Seriously, though, if you can't embrace running in the heat here in SoCal, you'll have some tough days on the race course.  Even with early starts, it can get hot by the finish and that's true into October around here.

It was 84 at 05:00 yesterday and today.  I didn't even bother to look at the index.

Run early AM or later in the PM, slow down a bit and carry fluids or place bottles along the route. 

But then I can't stand a TM workout. 

^^^^^^^^^^^^^^^^^^

Pretty much agree with this

Sometimes if it's too hot the run won't be a quality workout.

X2 or is it X3?   either way I agree with this.