Training In The South In The Summer

As a former competitive runner, and now a coach, who has lived his whole life in the southern United States, I have learned a good amount about effectively training for distance running in the hot and humid southern summers. On this blog entry I wanted to share some of what I have learned in the hope that maybe it can be helpful to you in your own running or that of your athletes.


Heat and Humidity

Running in warmer weather raises our body's temperature and one of the body’s main ways to cool itself during exercise is through sweat. We sweat and as the sweat evaporates from our skin it cools it down. The body then pumps more blood than normal to the skin in order to cool the blood and thus the tissue the blood then travels to. How quickly the sweat evaporates depends on the humidity (moisture level) of the air, at lower humidity it evaporates quicker and at higher humidity it does evaporate more slowly (if at all).

So we have a two different factors to think about - the temperature and the humidity level. The temperature will determine how much the body needs to cool itself down and the humidity will determine to some extent how hard it will have to work to do that. The combination of the two will determine how much harder our body has to work on the run than it does in more ideal weather conditions.

There is where Dew Point can become a good measure for a runner to look at to help take both heat and humidity into account.

Dew Point – Dew Point is essentially a saturation temperature of the air, so it combines humidity and temperature to some extent. To a large extent, the higher the Dew Point, the harder it will be for the body to cool itself during exercise. The higher the dew point the more miserable running in it becomes.

Adjust Your Runs For Summer Weather

As we just talked about, the body has to work harder when running in warmer weather, because it has to expend extra energy to try and cool itself. This means that a 5 mile tempo run done at 6:00 pace on a beautiful 50 degree fall day will not take as much energy or effort as it will to run those same 5 miles at 6:00 pace on an 85 degree summer day.

This means we have to adjust our pace or distance expectations during the warmer weather. If we do not we will end up working too hard and that can quickly lead to over-training, injury and burn-out.

So then, how much do we adjust our pace? I think the answer to that question depends on the temperature, humidity and dew point. The higher each is, the more have to adjust our pace.

As a general rule of thumb, we should adjust our pace roughly 0.75% for each 5 degrees above 60 degrees Fahrenheit. So a day when the weather is 80 degrees we would adjust our pace 3%. But this is just a temperature adjustment; additional adjustment may need to be made for humidity as well. I have a rough formula that I think helps me get in the right ball park when taking humidity into account. If humidity is between 40% and 60%, I add 3 degrees to the air temperature, if the humidity if between 61% and 80% I add 6 degrees and if the humidity is 81% or higher, I add 10 degrees. Like I said, it’s a little rough but gets me in the right ball park.

So let’s say we go out for our 5 mile tempo run one summer morning and our normal training pace for that tempo run in good weather is 6:00 per mile. But this morning the weather is 75 degrees and 85% humidity. Ok, so that is a little tougher conditions that normal. So we breakout our adjustment calculator and figure out what would be an equivalent pace given the heat. So we take the temperature of 75 degrees and adjust it by 10 degrees for the humidity to give us an adjusted temperature of 85 degrees. 85 degrees is 25 degrees above 60 degrees, so we adjust our pace by 3.75% (25/5 = 5 x .75% = 3.75%). Then we take 3.75% times 6:00 per mile (our normal tempo pace) and we get 13.5 seconds. This is the amount of time we would adjust our pace per mile. So on this day if we averaged 6:13-6:14 per mile it would be roughly equivalent to doing your tempo at 6:00 per mile on an ideal weather day.

Now this is just a rough calculation to help us get in the right ball park, but it seems to have held up pretty good over the years.

It is important to note that this formula helps you adjust for the extra effort you will use in a normal workout in the summer heat, but it does not adjust for any excessive dehydration or electrolyte loss you incur along the way. If you lose more than 2-3% of your body weight, in sweat loss, than your performance will diminish even more than the calculator shows. Dehydration and electrolyte loss is a serious concern during exercise during the summer heat. This comes into play even more so in our long runs and longer stress workouts. During these workouts, when the conditions get more extreme, simply adjusting your pace may not be enough, you may have to also adjust the distance as well. The guide I think we need to use here is based on feel. We want to finish our long run or hard stress workout in the summer with the same level of fatigue and needing the same recovery time, as we would in better weather and so need to adjust the pace and/or distance to accomplish this. If we do this then training during the southern summers become sustainable.

A great example of this came from last weekend. I had one of my athletes shorten her long run to 15 miles from the planned 17 miles because of the 74 degree dew point conditions. By doing this, she finished feeling like she had done the entire intended workout and was able to recover in the same time and is ready to go for her next stress workout. If she had been stubborn and pushed too hard in the heat in order to get in all planned 17 miles, she would have likely not been able to recover in time for her next planned workout. She got in the work we wanted, it just required 2 less miles to get there.

Signs of Dehydration

According to About.com’s Medical Review Board here are the common symptoms of dehydration (more than 2% body weight loss) in runners:

Early signs of dehydration include increased thirst; nausea; dry mouth; headache; reduced urine output, with dark yellow urine. Symptoms of moderate dehydration include extreme thirst; dry appearance inside the mouth; decreased urination, or lightheadedness. Serious dehydration can lead to cramps, chills and disorientation.

Adjusting Your Fluids and Nutrition

As we talked about earlier, summer running can greatly increase the amount we sweat, as the body attempts to cool itself. We need to recognize that the body is using a lot more water during this time that it does in cooler weather. We need to make sure we are replacing this water, and the electrolytes that are used in sweating, between our runs and during our longer runs and workouts.

During runs – we need to plan ahead and make sure we have access to water or sports drinks on a regular basis. This may necessitate stashing water bottles, running multiple loop courses or taking some fluids with us on our runs. Also don’t be afraid to help your body cool itself by pouring water on your head and body. That is water than can evaporate and cool that skin that your body doesn’t have to sweat out.

Before and after runs: make sure we are getting in some water before we start and then when we finish make sure we are replacing what we lost. But remember our body can only absorb so much at a time, so we may need to be drinking moderate amounts through-out the next several hours in order to completely replenish ourselves. And don’t forget the electrolytes and other vitamins and minerals we lose when we sweat, those need to be replaced as well.

Indoors

Sometimes the best option may be to run indoors. If it’s just too hot and humid outside to run safely (depends on your age, fitness level, and other factors), or we are still significantly depleted from a run out in the heat, the best course of action maybe to run indoors on a treadmill. Having this option available to you, and knowing when to use it, can help you maintain your summer training program and avoid over doing it.

Benefits

If managed properly, the adversity of warm weather training can help make us a stronger and fitter runner. It adds a different level of stress to the body which can act as a training stimulus. But this is only the case if we make the necessary adjustments to our training so that it is sustainable during the warm weather.

There are many who believe that warmer weather places unique recurring demands on the circulatory system, which can, if managed well, stimulate growth in the capillary system and blood supply in ways that does not happen in as readily in colder weather. Some even go so far as to say it may be as big of a factor as altitude training is in the success of the East Africans in distance running.

Attitude

As with any training stress, the attitude we bring into it plays a significant role in how well we deal with it. Warm weather is a just a fact of life in the summer in the south. If we dwell on it and become obsessed by it, it can ruin our summer and our training. But if we accept it, adjust accordingly, and even appreciate its benefits, we can have a successful summer of training and be even stronger runners come the fall.

Now bless your hearts ya’ll; get out there and enjoy some of this nice summer weather. :-)