You have undoubtedly done some running in the heat during the last week. Perhaps you have even spent some time strategizing about when to run. Should you depart early in the day before the sun comes up? Or, should you wait until evening when the sun has set. Maybe you decided to move inside to do some treadmill work in the air conditioning. What if I told you that you should stop avoiding summer heat and humidity and that there was a legitimate reason to do so for the sake of your training and fitness? I want you to embrace the heat. Do some training runs in the middle of the day. Slather on the sunscreen and get out there!
It turns out that running in the heat and humidity actually helps to replicate training at altitude. So, if you can’t join the running elites at Addis Ababa, Ethiopia (7,000 feet); Iten, Kenya (7,900 feet), Flagstaff, Arizona (6,834 feet); Mammoth Lakes, California (7,880 feet); or the US Olympic Training Center at Colorado Springs, Colorado (6,322 feet); take heart, you don’t have to adhere to USA Track and Field’s recommendation that athletes live between 7,000-8,000 feet of elevation; you don’t have to “sleep high and train low;” and you don’t have to convince your significant other to sleep in an altitude tent (It will not end well…). Instead, try going out in the middle of the day during the summer to achieve the benefits of altitude training.
What are runners trying to achieve through altitude training? It’s all about the oxygen. At altitudes above 5,000 feet, a lack of oxygen forces your body to create more blood cells and this, in turn, increases the amount of oxygen that can be carried to your muscles during exercise. A lack of oxygen at higher elevations actually stimulates the production of the hormone erythropoietin (EPO) that is made in the kidneys (The synthetic version of erythropoietin is commonly used in kidney dialysis, as well as in treating anemia. It is also the same EPO that was outlawed as an athletic performance enhancer in the early 1990s.). EPO triggers the production of additional red blood cells to transport sufficient oxygen to make up for the deficiencies at altitude. When returning to lower elevations, more oxygen delivery to an athlete’s muscles should increase aerobic capacity and endurance performance.
Sometimes, however, altitude training doesn’t work and no one is quite sure why. It might be that for some athletes, the stress of training at high altitude breaks down muscle fibers before the benefits of enhanced oxygen delivery can take effect. Genetics might play a role. This is also why the mantra “live high, train low,” has caught on in recent decades. The idea, here, is that one lives and sleeps at a high altitude to take advantage of hypoxia living, while training at a low altitude to prevent muscle breakdown. Living high and training low would appear to be the way to get the most benefit out of altitude (Verne Kopytoff, “Live High Train Low and Move Faster,” The New York Times, October 27, 1998). Is there another way to reap the benefits of altitude without risking muscle breakdown, altitude sickness, and the possibility that it just might not work? There is and it’s all about embracing the heat.
Training in the heat is not a novel idea. In the early 1980s, Olympian and 2:09 marathoner Benji Durden famously donned three pairs of sweats and rain gear during Atlanta summers to add heat as a training stressor. One of the key elements in both Deena Kastor and Meb Keflezighi’s lead ups to the 2004 Athens Olympics, where they both medaled in the marathon, was wearing full warmup suits, hats, and gloves during their summer training at Mammoth Lakes. The success of Florida Track Club members in the 1970s and 1980s also makes it clear that in addition to establishing a supportive place for post-collegiate runners to train, the club also provided an environment –– heat and humidity –– that made club members internationally competitive.
Olympians Frank Shorter, Jack Bacheler, Jeff Galloway, and local Capital Region legend Barry Brown, were members of FTC, and the popularity of the club increased after Bacheler’s success running in the high altitude of the 1968 Mexico Olympics. Shorter’s marathon victory at the 1972 Munich Olympics further popularized the FTC and confirmed the importance of heat and humidity as training elements. Finally, Grete Waitz –– virtually unbeatable during the late 1970s and early 1980s –– trained part-time in Gainesville, Florida, and participated in FTC events. The evidence looks clear: heat and humidity work.
Training in the heat does work slightly differently than altitude training, although the main outcome: increased oxygen delivery to the muscles remains the same. Training at higher elevations creates additional red blood cells, while training in the heat increases your blood plasma volume, which enhances circulation, oxygen delivery, and results in a higher VO2 max at a given effort level. Training in the heat will also increase your sweat rate, decrease your heart rate, and improve your running economy. The increases in strength and endurance resulting from your heat training should last for months if your training remains consistent. This is one big reason why people who have trained consistently in the summer heat often feel great when they start running fall races.
The other great thing about using heat training to simulate altitude adaptation is that the heat stimulus works more quickly. It usually takes 3-4 weeks to reap the advantages of altitude training. Unless you’re a professional runner, few people have the time to devote to a month of altitude training. Don’t despair, however, it appears that one can see performance improvements with as little as 5-7 days of running in the heat. As we’re finding out this summer, it is easy to do at home. Temperatures in the 80s have, unfortunately, been rather common.
While you should think about embracing the heat for some of your training runs this time of year, it is important to be careful. Be sure to adequately hydrate before going out to run in the heat. This means drinking water consistently the day before you plan a hard effort. Be sure to listen to your body. Obviously, this type of training is going to be uncomfortable (Hey, if it’s uncomfortable it’s probably a training stimulus.); if you discover, for instance, that you’re sweating profusely, but your skin is cold and clammy, you need to scale back your effort. Are you getting dizzy? Feeling nauseous? These are all symptoms of heat exhaustion and you need to stop and cool down. I recommend having a cool place with cool beverages ready when you complete your workout. Plan ahead! This kind of workout can be stressful. Be careful. If you do decide to embrace the heat rather than avoiding it, you will find that you will feel great when it starts to get cooler in the fall. You have increased your blood plasma volume and this has improved the oxygen delivery to your muscles, as well as greater overall efficiency. Running will feel easier and you will become faster. So, rather than bemoaning the hot summer, try viewing the high temperatures as just another training stimulus and another opportunity to improve your running. Remember to hydrate properly and watch for signs of heat exhaustion and you might find that you are looking forward to some runs during the heat of the summer.
The author partakes in some very necessary cool beverages after a tough run in the summer heat.