02Giant 

I’ve rode in 95 degree temps with the max humidity possible at that temp. Those are few and far between, my summer riding starts as early as 5am.

Rides4Beer

I see a lot of runners and cyclists here in SC complaining about the heat, but then I also see the same people avoiding the heat. You can't get acclimated if I you sit in the a/c all day and only run/ride when it's cool. The only way to acclimate is to suck it up and get out there in the heat. Usually only takes me a week or two when it first warms up and I'm good. But I make myself go out in the sun and heat, sometimes I'll go in the middle of the day on purpose. I work in an air conditioned office, but I'll usually drive with the windows down and the a/c off. Then I spend the rest of the summer enjoying the outdoors while watching people suffer and look miserable.


Dew point is probably the best indicator of conditions, because that will let you know when your sweat isn't going to evaporate and keep you cool. Anything above 70 is just gonna suck, so I drink a lot and know that I'm gonna be soaked. You also have to adjust your effort when the dew point is high. A lot of people get discouraged because they're not hitting the workouts the way they expect in the heat, but your body only knows effort, so the same effort, even if it results in a slower pace/speed, will still yield results.


Just water for me for most rides up to 2-3 hours. If it's a long ride/event, then I'll eat, and maybe drink a lil gatorade at an aid station or store stop, but still mostly just plain water.

Litespud

It’ll get to 96F tomorrow. Our regular group ride (~50 mi) heads out at 8, which is too late for me. I’ll probably head out at 6 for a solo ~70, aiming to get back around 10. It’ll still be hot by then, but not stupid hot

wphamilton

Yep. I'd say he was 90% correct not 100%, because I see a strong drop-off in the number of cyclists out when the temperatures rise.

pdlamb

I can't remember who said, "Hot is 10 degrees warmer than you're used to." He was spot on, IME.

I can survive anything I've run into for an hour, up to 114F (with a dewpoint down in the 60s). Make a quick dash, run inside, cool off. If you're talking about all day rides, that's when I'm limited by how much heat I can shed and how much fluid I can absorb. In the 90s and low 100s, with typical 50-70% RH, I can sweat out twice as much as my stomach and gut can absorb (2 qts./hr vs. 1 qt./hr). Once I've lost 6 pounds or so, the riding gets progressively tougher.

bobwysiwyg

I'm sure I have a high temp limit, but humidity will do me in sooner. We rarely have more than six 90F days each year. Even those can be dealt with by riding earlier, but the humidity.. ugh!

MoAlpha

Yep. Dew point temp is the critical parameter for hyperthermia, especially in athletes exposed to moving air.

rydabent

Pretty much anything over 100 degrees.

JasonD67

Just got back in from a ride after work...98 here and the dew point 72. Nasty. I realized how useful my HRM is in these conditions. On a "normal" day I often go into zone 4 when riding along. Today when I looked down just cruising, feeling good, and I was in in zone 4 I told myself "Whoa there!" and backed it down 'till I was back in zone 3 and even 2. Staying in high zone 3 and low 4 for an extended time in these conditions will lead to bonking at the least, or heat exhaustion at the worst.

sallen73

Commuting? No such thing as too hot; I just go slow(er), try and pick the shadiest routes through the city and make an effort to drain two water bottles between work and home (approx. 8 3/4 miles each way). As miserable as I could ever possibly get ti will still be a lot less miserable than being on the El. Which will invariable pull out of a station then stand for 15 minutes waiting for a train that broke down (or is the train that broke down).

Exercise? Don't care; I will make every effort to get out on a dawn patrol so I am limited only by myself and not traffic, crowds, other trail users, (you know, the world!). Alternately I will go out at or after sunset, but those rides tend to be shorter and slower.

Errands and Just Because rides? I usually start to think twice when the temps are in the upper 80's, especially if the sun is shining; once the temps hit the mid to upper 90's I leave the bikes parked.

Kapusta

It depends.

Humidity makes a big difference.

It also makes a difference whether I am riding the road or mountain biking. If it is really sunny and hot I prefer the woods to blacktop.

It also makes a difference how long the heat will last. If it is just a few days (like the current situation) I'll just wait it out. But after a few days I will get desperate to ride and just suck it up.

Slightspeed

Usually 100° or so, though I once did a "double century", 102 miles in 104°. 2010 Lighthouse Century.

TimothyH

Everyone should read this...

Monitoring heart rate is a really good point.

Excellent post.


-Tim-

big chainring 

I rode near the lakefront in north Chicago burbs at noontime. 90 degrees, 70% humidity. Got to this point in Highland Park where there is almost always a cool breeze. Tried to convince myself I felt it.

alloo

I rode today in 101F. I use my cooling vest from motorcycling over my jersey. I think in the future, I would use my cooling vest over my tshirt as it seems to keep me cooler that way and I don't have to refresh the vest with water. It makes sense. https://www.summitracing.com/parts/t...oaAqkmEALw_wcB The vest keeps my body temperature low.

Gresp15C

It was about 95 F and maybe 75% humidity today on my ride home from work. It didn't really seem all that bad. I'm fairly acclimated to it. I didn't ride super fast, and it was only 4 miles plus a brief detour to Target on the way home.

I can expend less effort riding than walking, so that's possibly a factor. There were noticeable differences in conditions depending on whether I was going through greenspace or concrete jungle.

MikeyMK

I'm guessing over 50oC. I've ridden in 36oC and that was fine. In fact, it only became intrusive when I stopped. But then, I was cruising, occasionally riding with an ice cream, not trying to give myself a heart attack.

2manybikes

It was a few degrees cooler down at the water today. The plan was to come home and feed the dog halfway through my ride. I was too hot when I got to the house. Changed my clothes and went to the ice cream place about a block away. Too hot to walk the dog even....

canklecat

Hottest ride was last July, 111 F. And we had several days over 100. Rode anyway.

June is usually my month to acclimate. That's when the temperature can often go from cool and pleasant to hot without much transition. Sure enough, I was pretty exhausted after most rides of any length or duration in June. But by now I'm adapted.

But I don't push myself beyond my comfort zone. If I'm in a group ride and begin to feel like the heat is getting to me, I let 'em go. Either I catch up at a regroup point, or take a different route and head home. And I'll tend to start rides around 5 pm or later. It's still hot but cools off quickly as the sun goes down. I'm not a morning person, and even early morning long rides are getting hot by the end of the ride. When I start late, the weather gets cooler as I'm getting tired. Easier overall. Just demands a little more weight to carry lights.

Hydration seems like such a cliche, but I see so many folks doing it inefficiently. Main problem I've seen this year has been folks drinking plain water, or going overboard and taking salt tablets in addition to electrolytes. Occasionally they're taking less effective electrolytes.

To be effective it should be a balance of electrolytes and sugar. The sugar helps us absorb the fluids more readily. Plain water often causes bloating. Salt tablets make it worse -- it draws fluid out of the body and into the stomach.

Best stuff I've found is DripDrop. Comes in single serve Mylar packets, weatherproof and sweat proof. It's formulated to aid rapid absorption of water, as an alternative to IV fluids. I've given away a few packets this summer to cyclists who were on the verge of heat exhaustion, including one who passed out and vomited.

I've tried others -- Propel, NUUN, Hammer, several others -- but DripDrop is the best I've found so far. Nothing magical in it, but an optimal balance of ingredients.

Rollfast

When the neighbors along the way keep their dogs in the house.

DHPflaumer

I generally stop doing fun rides when the weather breaks 100F. I will, however, still do my commute.

terrymorse 

Thanks for recommending DripDrop. I had a nasty experience with hyponatremia (inadequate sodium) in a hot race before, so I’m going to try carrying some DripDrop in my saddle bag. Maybe it will keep me out of the ER.

Spinay70

Ride when its comfortable to you. Unless you are a pro - then someone will tell you when to ride

Spinay70

Arthur Peabody

I live in Albuquerque, have ridden in 100°, weather I couldn't have comfortably walked or run in, but I have to keep moving. Twice I have had bad falls, had to walk, which was torture. I stopped at a fast-food joint with unlimited soda pop and AC, sat down for a few hours, gotten my 99¢ worth. As soon as I get home, I over-heat terribly, take a cold shower as long as I can stand. Time spent fixing a flat is also terrible. I had to take breaks to walk to cool off.

moto367

I've been fortunate to have never too much of an issue with the heat. Acclimation has always been the key for me along with proper hydration. I asked the opening question mainly out of curiosity. The local news channels are making this heat wave out to the one of the ages. It kind of makes me chuckle. I think you really have to know your body and how it reacts to situations and being smart to know when to ease up and ride for another day. Good responses from all.