Cycling in Heat and Humidity

As we roll into the dog days of summer, we’re subjected to the hottest and most humid days of the year. So let’s be a little extra cautious when exercising.

How does the body cool?

There are four mechanisms that our bodies use to cool off: Radiation, Evaporation, Conduction, and Convection.

  • Radiation is the heat leaving the body into the surrounding atmosphere.
  • Convection is air (or water if you’re swimming) flowing by the body, taking away heat.
  • Evaporation is your sweat evaporating, causing a cooling effect.
  • Conduction is your skin coming into contact with something cooler, transferring heat.

Radiation, Convection, and Evaporation are all our friends and work together perfectly to keep us cool. Conduction, not so much in cycling. Unless you hold that frozen water bottle to your neck for a quick relief.

However, if the temperature outside is hotter than our bodies, radiation cannot work. The heat goes in the other direction into our bodies.

And if the air is very humid, evaporation cannot work.

Luckily, convection is always at play when we’re moving at 20mph, and it still feels good.
But when you stop, boy can you feel it.

The downside of the efficient cooling effect that we get from cycling is that we can feel more comfortable than we should. And dehydration is a big risk.


Many cyclists say, “Drink before you’re thirsty”, which is great advice especially in hot weather. This is not the time to pack light with only one water bottle. And make it a point to take a sip every 15 minutes, or 5 miles, to replenish what you’re losing.


When it’s super hot and humid, plan to take it easy on yourself. Maybe do a recovery pace. Or map out a route that doesn’t have your normal hills. (thought he downhills are always good for cooling off).

Or if you’re on a longer ride, be sure to loop in a place to refill the water bottles.

What to drink?

When it’s hot and humid, the most important thing is water. You can go with your electrolytes and sugary drinks, but I always like to mix it up with both a sports drink and some plain water to wash it down.

What to wear?

Nothing would be best. But if that doesn’t seem appropriate (there are lots of naked bike rides you can join), wear something that the wind can get through, and this is a great time to choose the shirt with the full zipper front.

Most importantly, take it easy, and listen extra carefully to what your body is telling you.

Stay safe.

Lumos Bicycle Helmet with Integrated Lights

I don’t ride at night often, but when I do, my lights are always dead. Or I don’t have them with me.
But if integrated with my helmet, I think I’d remember to keep it charged, and I’d certainly not be without that.

What a great concept, automatic brake lights, always on blinking rear and front lights, turn signals… yeah how about keeping your hands on the bars while signaling a turn in traffic? nice.

Sometimes the simplest ideas are the best. Unfortunately, it’s a year away. I have no doubt this one will get funded.

Check it out on Kickstarter. The early bird offers of $85 for your own helmet are still available.

UPDATE after a day, this kickstarter is funded, and then some. The early bird offer is gone, but there are others. Hurry!

The ultimate bicycle helmet with brake lights and turn signals to help cyclists stay safe and visible on the road.

We Have Met The Enemy and He is Us

Road rage is a serious problem for cyclists. If you’ve ridden any amount of time, you’ve certainly experienced the extra loud horn, the close pass, the over-revved engine, shouts, and the hand gestures.

And at the same time you’ve probably thought, “What the F***?!? I wasn’t doing anything. Jerk.”

Where does the road rage come from?

Well, I saw them today. From the perspective of a driver. The reason for all the road rage.

I was driving through my small town today, which is itself a small slice of cycling heaven. Lots of cyclists start here or ride through here. I often get groups of 30 riders coming past my house on big club rides, and there are endless solo or pairs coming through all the time.

The roads are narrow, there are few painted lines even, blind corners and hills, and there are no sidewalks. Just road and soft shoulders. It’s a place where drivers and cyclists truly need to co-exist.

There’s one particular fun hill to climb and descend. It’s about a half mile up and another half down. The downs end at stop signs.

I was driving my kids to camp this morning heading up this hill as I approached a line of three cars stuck behind a group of four cyclists, and I quickly caught up. The car in front couldn’t pass because the group was pretty well oblivious to the fact that there were cars lining up behind them. They were attacking the hill, standing, riding hard, bikes jerking back and forth as happens in a sprint, passing each other erratically as in a race. It was pretty well impossible to pass safely, or at least comfortably, in a car even though they were going well under the speed limit up this hill.

They reached the top of the hill, still without allowing anyone to pass, and bombed down the descent, pulling ahead of the cars. (No problem with that part.)

Until they reached the bottom, where they took a left turn at a 4-way stop at full speed. In full view of at least 4 motorists who are already watching closely and shaking their heads at these guys.

Inconsiderate and reckless. And damaging to the entire cycling community.

Now these guys are serious cyclists. They know what they’re doing. They all wore the kit from a local racing club.

They are too serious, apparently, to care.

I’m no stickler for traffic rules on the bike. I’ll run stop signs, but certainly not without slowing down, and only if I can see that there’s no cars around, or at least if there are, if I have eye contact of a driver who is letting me go through. And I’ll wave thanks.

And if I’m at all in view of motorists, I’m much more careful about how I behave. Because I know that they’re watching and judging.

Does this make me any better than these guys? I don’t know.

How we behave affects all of us.


So in the comments, I got called names by another cycling blogger about this post.

Here’s the intersection. The guys came through here at at least 20mph and took that blind left at speed.

It’s a 4-way stop sign. So it’s pretty safe to assume that all cars will stop. But that’s not really the point. There’s also the law that cyclists should stop just like cars. That’s also not really the point. I roll through stop signs all the time.

This was just a reckless display. that gives us all a bad rap.