My wife and I were walking the other day and we were enveloped in the humidity that defines Washington, DC summers. As a native of North Carolina, she refers to the humidity as a comforting blanket. Because I grew up in Connecticut, I tend to have a different view and have a really hard time running in the heat in humidity. But because it’s not only my job to make sure that I am in shape so that I can keep up with the kids I coach come fall, but I also love running, I had to find some ways to adjust in the heat of the summer.
While I’ll get into the science behind how heat affects exercise below, I want to start with a personal story. In 2012, I was training for the National Marathon (now Rock ‘n Roll DC). My buddy and I trained through a winter that saw snowstorms and frigid temperatures. Having run in college in upstate New York, I have to say I reveled in it. While this could be a bit of a revisionist history of the weather, we dutifully completed our long runs regardless of the temperature or weather conditions. As race day approached, there were some perfectly cool days leading up to the race that would have been awesome for marathon running.
Of course race day arrived and it was in the high 60s at the start and when I crossed the finish line, it was 77 degrees. Needless to say, the heat had a significant effect on how I ran that day. Even though I came away with a PR, I was always left wondering what could have been if the race had been run in cooler temperatures.
The important take away from the race and the subsequent disappointment with the weather is we have to do the best we can with what we are given. That day was warm and I tried to drink fluids constantly. And while I wish it had been cooler, I did my best to control the variables I could.
While I’ll get into the science behind how heat affects exercise below, I want to start with a personal story. In 2012, I was training for the National Marathon (now Rock ‘n Roll DC). My buddy and I trained through a winter that saw snowstorms and frigid temperatures. Having run in college in upstate New York, I have to say I reveled in it. While this could be a bit of a revisionist history of the weather, we dutifully completed our long runs regardless of the temperature or weather conditions. As race day approached, there were some perfectly cool days leading up to the race that would have been awesome for marathon running.
Of course race day arrived and it was in the high 60s at the start and when I crossed the finish line, it was 77 degrees. Needless to say, the heat had a significant effect on how I ran that day. Even though I came away with a PR, I was always left wondering what could have been if the race had been run in cooler temperatures.
The important take away from the race and the subsequent disappointment with the weather is we have to do the best we can with what we are given. That day was warm and I tried to drink fluids constantly. And while I wish it had been cooler, I did my best to control the variables I could.
The 2012 Boston Marathon was an example of how heat can decimate a field of highly trained runners. Finishing rates and times were significantly off historical trends and more than 2,100 runners were treated for heat-related illnesses. With temperatures in the 90s, it’s not surprising.
Multiple exercise science studies have tried to measure the affect heat has on runners. One such study entitled "Impact of Weather on Marathon Performance" published in the journal Medicine and Science in Sports and Exercise, author Matthew Ely and his co-authors examined marathons as they related to race day temperature. Results and weather was collected for several major marathons including Boston, New York, Twin Cities, Richmond, Grandma's, Hartford and Vancouver over periods of 6-36 years. The authors compared the top three finisher’s performances with course records for the appropriate time frame, and also compared performances of "slower" marathoners (the 25th, 50th, 100th and 300th place finishers) with those course records. Both males and females were studied.
As you might imagine, their findings were consistent with my story above; heat has a significant effect on how fast you run in the marathon.
Here is a graph of their findings:
Multiple exercise science studies have tried to measure the affect heat has on runners. One such study entitled "Impact of Weather on Marathon Performance" published in the journal Medicine and Science in Sports and Exercise, author Matthew Ely and his co-authors examined marathons as they related to race day temperature. Results and weather was collected for several major marathons including Boston, New York, Twin Cities, Richmond, Grandma's, Hartford and Vancouver over periods of 6-36 years. The authors compared the top three finisher’s performances with course records for the appropriate time frame, and also compared performances of "slower" marathoners (the 25th, 50th, 100th and 300th place finishers) with those course records. Both males and females were studied.
As you might imagine, their findings were consistent with my story above; heat has a significant effect on how fast you run in the marathon.
Here is a graph of their findings:
There are a few running calculators that you can use to see how much you may slow down based on heat and humidity. One is Jack Daniel’s famous calculator. Joe Vigil also has a great chart in his book Road to the Top. What’s important to recognize is that there are a lot of factors (weight, fitness level, where you grew up, etc.) that will dictate how much your performances might suffer in the heat and a calculator won’t be able to work with all of those variables. So make sure to experiment and track how you feel after your run.
Now that you know a little bit of the science behind why runners slow down in the heat, let’s see how we can combat this weather so that when the fall race season comes around, you’re ready to roll.
But Why?
There are many physiological effects that take place when your body is first exposed to exercise in high heat, including your ability to maintain blood flow to active muscles and the ability of your blood to transport oxygen to those muscles.. It takes approximately two weeks for your body to adjust to higher temperatures and during that time, you may experience the sensation that you’re out of shape!
1. Be OK with a slower training pace in the summer months: Just because you’re not running intervals at the same speed that you can when it’s 50 degrees, doesn’t mean you’re in any worse shape. In fact, studies on cyclists have shown that training at appropriate paces for the current heat and humidity will not only allow you to adapt faster to the weather, but will also allow for bigger gains once the temperature cools off. Those cyclists who trained in the hot weather were a few percentage points stronger than the cyclists who trained in the “optimal” weather during the same period. Recognize that it’s OK to slow down in the summer and that it doesn’t mean you’re losing fitness!
2. Make sure you stay hydrated: Loss of 2% of body weight through sweating will have a significant impact on your performance. There has been a lot of debate about how much water is the right amount of water when you’re exercising in the heat. Tim Noakes, author of Lore of Running, has done a lot of research on this in his recent book Waterlogged. At the end of the day, a good rule of thumb is to drink when you’re thirsty. That being said, people’s sweat rates vary considerably. A good test is to weigh yourself before you run in hot weather and then again after you finish. This will give you a good idea of how much fluid you lose over a set time and from there you can calculate how much you need to replace after running. As I said before, I really struggle in the heat and part of that is due to the fact that I sweat a lot when I’m running! When I ran my marathon PR, I took in double the amount of fluids that my training partner did. After working out, sports drinks like Gatorade and Powerade are great ways to rehydrate because your body is craving those electrolytes.
When I am not running in the city where I have access to water fountains, I bring a water bottle to stay hydrated. Starbucks is also a great place to stop and get water along the way. Don’t worry about the brief rest you take when you’re drinking fluids, it will be worth it in the long run.
3. Wear the right clothing: I wear a hat when I am running because I have lost a lot of my hair and so I need to keep my head covered. When it’s hot out, the hat does trap some heat. That being said, I love the Nike Featherlight hat because it breathes well and still protects my noggin from the sun. I also stay away from cotton. Fabrics that breathe have revolutionized running gear in the past decade. It’s a far cry from the cotton race t-shirts I used to wear!
4. Run in the morning or the evening: I have had to adjust my schedule to get good runs in. Even though I’m not a morning person, if I want to get a solid effort in, the 6 o’clock hour is when I can do my best running. The heat and humidity stick around too late into the evening in DC for me to run at that time. Running after the sun has gone down serves the same purpose.
5. Cross-train: When all else fails and it’s just too hot, get on a bike or in the pool. Even though it may be a bummer to not go running, recognize that male triathletes can split under 30 minutes for the 10k after biking and swimming. As a result, give yourself permission to do an alternate workout. Your heart rate will still be elevated and you’ll still get aerobic benefits. It’s also a great time to get a little extra strength work in!
6. Acclimate to the heat: As coaches, we always err on the side of caution and when temperatures are at dangerous levels, we try to avoid exercise. That being said, if you truly want to run well, but the race day forecast calls for higher temperatures, then you must acclimate your body to the heat. As stated above, athletes who are in great shape may struggle if they haven’t acclimated properly to temperatures -- this goes for heat AND cold weather. What is important to note, heat acclimatization cannot take place unless you safely build up to running in higher temperatures. It is not sufficient to just “be outside” on a warm day; you must train to prepare. Acclimatization effects begin to take place during the first week of training in the heat, as the body begins to make adjustments to lower heart rate, skin temperature and core temperature. Increased sweat capacity (the body’s way of reducing skin temperature), and a reduction in blood flow to the skin (resulting in higher volume of blood available to return to the heart) also take place during this acclimatization period. These adaptations lead to an athlete’s ability to be better prepared to succeed when competing in heat.
7. Ease into it!: Working out if you don’t feel like you are in good physical condition. An athlete who isn’t in good shape to begin with is at increased risk for heat-related injuries when training in heat.
Do you have any tips or tricks for the heat? Let us know!
Now that you know a little bit of the science behind why runners slow down in the heat, let’s see how we can combat this weather so that when the fall race season comes around, you’re ready to roll.
But Why?
There are many physiological effects that take place when your body is first exposed to exercise in high heat, including your ability to maintain blood flow to active muscles and the ability of your blood to transport oxygen to those muscles.. It takes approximately two weeks for your body to adjust to higher temperatures and during that time, you may experience the sensation that you’re out of shape!
1. Be OK with a slower training pace in the summer months: Just because you’re not running intervals at the same speed that you can when it’s 50 degrees, doesn’t mean you’re in any worse shape. In fact, studies on cyclists have shown that training at appropriate paces for the current heat and humidity will not only allow you to adapt faster to the weather, but will also allow for bigger gains once the temperature cools off. Those cyclists who trained in the hot weather were a few percentage points stronger than the cyclists who trained in the “optimal” weather during the same period. Recognize that it’s OK to slow down in the summer and that it doesn’t mean you’re losing fitness!
2. Make sure you stay hydrated: Loss of 2% of body weight through sweating will have a significant impact on your performance. There has been a lot of debate about how much water is the right amount of water when you’re exercising in the heat. Tim Noakes, author of Lore of Running, has done a lot of research on this in his recent book Waterlogged. At the end of the day, a good rule of thumb is to drink when you’re thirsty. That being said, people’s sweat rates vary considerably. A good test is to weigh yourself before you run in hot weather and then again after you finish. This will give you a good idea of how much fluid you lose over a set time and from there you can calculate how much you need to replace after running. As I said before, I really struggle in the heat and part of that is due to the fact that I sweat a lot when I’m running! When I ran my marathon PR, I took in double the amount of fluids that my training partner did. After working out, sports drinks like Gatorade and Powerade are great ways to rehydrate because your body is craving those electrolytes.
When I am not running in the city where I have access to water fountains, I bring a water bottle to stay hydrated. Starbucks is also a great place to stop and get water along the way. Don’t worry about the brief rest you take when you’re drinking fluids, it will be worth it in the long run.
3. Wear the right clothing: I wear a hat when I am running because I have lost a lot of my hair and so I need to keep my head covered. When it’s hot out, the hat does trap some heat. That being said, I love the Nike Featherlight hat because it breathes well and still protects my noggin from the sun. I also stay away from cotton. Fabrics that breathe have revolutionized running gear in the past decade. It’s a far cry from the cotton race t-shirts I used to wear!
4. Run in the morning or the evening: I have had to adjust my schedule to get good runs in. Even though I’m not a morning person, if I want to get a solid effort in, the 6 o’clock hour is when I can do my best running. The heat and humidity stick around too late into the evening in DC for me to run at that time. Running after the sun has gone down serves the same purpose.
5. Cross-train: When all else fails and it’s just too hot, get on a bike or in the pool. Even though it may be a bummer to not go running, recognize that male triathletes can split under 30 minutes for the 10k after biking and swimming. As a result, give yourself permission to do an alternate workout. Your heart rate will still be elevated and you’ll still get aerobic benefits. It’s also a great time to get a little extra strength work in!
6. Acclimate to the heat: As coaches, we always err on the side of caution and when temperatures are at dangerous levels, we try to avoid exercise. That being said, if you truly want to run well, but the race day forecast calls for higher temperatures, then you must acclimate your body to the heat. As stated above, athletes who are in great shape may struggle if they haven’t acclimated properly to temperatures -- this goes for heat AND cold weather. What is important to note, heat acclimatization cannot take place unless you safely build up to running in higher temperatures. It is not sufficient to just “be outside” on a warm day; you must train to prepare. Acclimatization effects begin to take place during the first week of training in the heat, as the body begins to make adjustments to lower heart rate, skin temperature and core temperature. Increased sweat capacity (the body’s way of reducing skin temperature), and a reduction in blood flow to the skin (resulting in higher volume of blood available to return to the heart) also take place during this acclimatization period. These adaptations lead to an athlete’s ability to be better prepared to succeed when competing in heat.
7. Ease into it!: Working out if you don’t feel like you are in good physical condition. An athlete who isn’t in good shape to begin with is at increased risk for heat-related injuries when training in heat.
Do you have any tips or tricks for the heat? Let us know!
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