What is Dew Point?

Every Spring I look forward to so many things. The smell of the blooming trees and flowers coming back to life, the warm evenings, the excitement of my children in their last quarter of school, the return of the ever popular shorts and flip flop attire that is 9 months long in Florida. The animals are all out, the snakes are back moving,beach days are without sweltering heat, and the sweet sound of my phone blowing up with text messages of fear and anguish about how my runners can no longer run. What did I say? Yes, you just read that. Every year my clients, around March and April, think they can no longer run. It truly is as consistent as changing the clocks every year. All winter long personal record after personal record is accomplished. Clients are brimming from ear to ear at the joy that comes when they reap the benefits of their smart and consistent training. As a coach, especially from New England, it was difficult for even me to figure out what the problem was. As runners we are already headcases, trying to figure out good information from bad information, tired legs vs overtrained legs, good fatigue vs bad fatigue, too little miles vs too many. Since over analyzing things is our specialty, it is no wonder my phone never stops with questions. Normally I pride myself in being able to talk a runner back off a cliff after a bad run but it was becoming increasingly difficult each spring, and the more clients I got the worse it got. Common denominator? Yes! It became apparent to me that something was truly a problem for runners in Florida and I needed to figure it out so I could help myself, and my runners, learn to cope with the reality that is training in Florida.

I have run in the heat many times, in fact I lived in Memphis, Tennessee for four years between many years in Maine and Massachusetts. Memphis is hot in the summer with highs very likely to be between 98 and 102, with very high humidity. So I had many experiences with races in this weather. The difference in Memphis is that when it is hot, it’s hot. Some people race better than others in hot. I am not one of them, so on a hot day I knew, it was probably not going to be a personal record, but it was OK with me. No freaking out or panic attacks, just stay as hydrated as possible and then move on to the next race. Florida has been different, but why? I will tell you why. It is because of something that most people don’t pay attention to. First, it is because they don’t understand it. Second, because they have lived here their whole lives and are just used to it and third, because they don’t run. Dew Point.

What is dew point?

“It is the atmospheric temperature (varying according to pressure and humidity) below which water droplets begin to condense and dew can form.”

This is the literal textbook definition. Now let me explain. The air we breathe is roughly 20 percent oxygen, 75 to 80 percent nitrogen and the rest is various small amounts of other gases like carbon dioxide, argon and methane.

I know you are thinking where in the world is this crazy coach going with this? In the spring the temperature is still pretty low with temperatures in the morning ranging from 60 to 70. Comfortable temperature to run in right? Depends. It depends on the air and it’s oxygen saturation. Oxygen is very important. Normally your body obtains oxygen from the air you breathe. From there it enters your blood stream and carries it to your muscles where some of it is used and some of it is stored.Whether exercising or not, it is used to breakdown glucose in your body to be used for fuel. When exercising, the demands for oxygen are greater as your need for energy is increasing because your muscles are working harder. This is why the harder

you are working, the heavier your breath is. So what does this have to do with dew point? Essentially the higher the dew point the more the air is saturated with water and the less room there is for much needed oxygen for your working muscles. So how does this affect how we train?

1. The closer the temperature is to the dew point the more trouble you are in as the air is very saturated. So for instance if the temperature is 70 and the dew point is 70 that is 100 percent trouble. No matter how hard you try your body is struggling to get the oxygen it needs even though 70 feels pretty cool to the skin.

2. When you are running your body temperature rises. To cool your body it produces sweat. If the air is full of water already, it is difficult for it to evaporate from your body as it should to cool you, therefore your body temperature can increase which is dangerous.

3. After the evaporation fails at cooling the body, it then produces more sweat which then makes it fairly difficult to stay hydrated. Once one becomes dehydrated performance can drop up to 30 percent.

4. If the temperature increases, your heart rate does as well. After 75 degrees it can increase by as much as 10 beats per minute so your body is working harder to maintain the same paces.

It truly is a vicious cycle. So what do we do? How do we adjust? And are there any up sides to knowing this information? I use a formula for my runners so they can adjust their race paces accordingly. Take the temperature and the dew point and add them together. If the number is

100 or less no adjustment.

110 to 120 1% adjustment

120 to 130 2% adjustment

130 to 140 3 % adjustment

140 to 150 5 % adjustment

150 -160 8 % adjustment

170-180 10 % adjustment

180 plus running not recommended.

(Example 70+70 =140 if your race pace is 8:00 minute pace 5% adjustment of 8:00 minute pace is 8:24)

Tips for training:

* Train by overall time vs. mileage,as it is important to slow your training paces if the dew point is high. Change your mind set! Just run easier! Find a nice comfortable pace and stay there.

* Try to run more on perceived exertion instead of trying to hit certain numbers. If you have been training at tempo pace in the winter then you know how tempo feels, so go by feel.

* Instead of stressing about hitting your track workouts perfectly, do fartlek workouts where you surge from light pole to light pole or mailbox to mailbox or better yet water fountain to water fountain.

* Stay hydrated drink water and take electrolytes and use your thirst as your guide. Your body is smart-listen to it.

* Keep training in it! The more you train it the Florida weather the better adapted you become.In the spring be kind to yourself and allow yourself to adjust back to the higher temps and dewpoints. It is very hard to train in Florida be proud of how tough you are, just be smart!

* Put ice in various spots in your bra, shirt, shorts, hat, whatever you can it will cool you

* Wear sunscreen and a visor.

Is there a positive side to all of this? Absolutely. 2012 Boston Marathon. I lived there and trained all winter for the marathon. Most of my long run were in 15 degrees or under in the middle of February in the miserable wind, snow and ice. I felt like a pretty tough runner. Nothing was going to stop me race day. Until race day. Usually in Hopkinton on Marathon Monday, we are huddled together in layers of clothing trying to stay warm. 2012 was different. It smelled like the beach on a hot summer day. The temperature was a balmy 85 with dew points in the 60s. The day before the race, it was 60 and the day after 65. I wondered for a moment what I was thinking standing there and wasn’t about to let a little heat get to me. I was ready. Or so I thought. I will never forget that moment at mile 8 when I knew it was not going to be anywhere near a PR, and I was struggling so much already that this woman blew by me like I was standing still. As she passed me, I said “way to go girl! Killing it on a hot day!” To which she replied, “I’m from Texas, this is nothing!”. Remember on all your hard runs in the heat you Floridians that you are truly ready for anything. It is a definite advantage because if any of those northerners trained for a marathon up there, and then came and raced one of our races, they would be truly happy to finish. Embrace the pain and know you can take on any weather out there!