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HPRC Fitness Arena: Environment
With the summer weather here to stay for a few months, HPRC wants to remind you of the dangers of heat illness and the importance of staying hydrated. This information can relate to any outdoor activity such as exercising, hiking, bike riding, or playing in the park.
HPRC has tips on preventing heat-related illness and various guidelines for avoiding heat injuries. Hydration is an important factor for keeping you and your loved ones happy and healthy. Children need to be careful as well since they seem to have an infinite amount of energy while playing outside. In addition to water, sports drinks can also be beneficial. Keep this information in mind while you are out and about with your friends, family, and pets. Happy Summer!
Inhalation of major air pollutants has been found to decrease lung function and exacerbate symptoms of exercise-induced bronchospasms, including coughing, wheezing, and shortness of breath. In order to meet oxygen demands during light- to moderate-intensity exercise, you take in more air with each breath. And when you breathe through your mouth, you bypass the nose’s natural filtration of large particles and soluble vapors. As your exercise intensity increases, you breathe faster and deeper, which also increases the amount of pollution inhaled and the depth it travels into your respiratory system.
If you live in or near a busy city, you are exposed to even more combustion-related pollutants—such as nitrogen oxides (NOx), carbon monoxide (CO), particulate matter (PM), and ozone—that can inflame your airways and worsen asthmatic responses. Exposure to freshly generated emissions is most common near areas of high vehicular traffic.
While indoor exercise is often a good alternative to limit exposure to outdoor pollutants, some indoor conditions may be just as toxic. Nitrogen dioxide (NO2)—the more toxic NOx—is usually higher in gas-heated homes and indoor areas with poor ventilation. Carbon monoxide poisoning is also more likely to occur indoors. When carbon monoxide is in your system, the blood carries substantially less oxygen, reducing performance and eventually leading to carbon monoxide poisoning. Be sure to choose well-ventilated areas for indoor exercise.
Particulate matter and ozone are two significant pollutants you may be exposed to outdoors. Inhalation of high levels of particulates has been shown to reduce exercise performance as much as 24.4% during short-term, high-intensity cycling. Women may be more vulnerable than men to certain particulates, associated with greater decrements in performance. Ultrafine particle concentrations are highest in freshly generated automobile exhaust, and these small particles can be carried deep into the lungs. However, the further away you are from fresh exhaust, the less concentrated the particulates.
Bad ozone occurs lower in the atmosphere; it is not directly emitted into the air but is created from chemical reactions between NOx, volatile organic compounds (VOCs), heat, and sunlight. Ozone levels also are higher in summer than in winter; and especially in larger, hotter cities, concentrations tend to peak around midday when solar radiation is highest. Exposure to ozone during exercise has been found to increase resting blood pressure, reduce lung function, and decrease exercise capacity.
The risks associated with not exercising at all are far greater than the risks of exercising outdoors; it just takes a little more planning on days and in conditions when pollution is bad. When planning outdoor exercise activities, follow these tips to limit your exposure to pollutants:
- Avoid exercising in areas of heavy traffic, such as along highways and during rush hour.
- During summer, exercise earlier in the morning, when ozone levels and temperatures are not as high.
- Check the domestic or international air-quality ratings to determine if it’s safe to exercise outside. Limit your time outside on Code Red and Code Orange days. Environmental conditions on these days are not healthy, especially for children, the elderly, and people with existing respiratory conditions.
- Exercise indoors when the air quality indicates high ozone and particulate levels.
- Before any demanding physical activity, limit your carbon monoxide exposure by avoiding smoky areas and long car rides in congested traffic.
The goal of National Nutrition Month is to remind Americans to eat healthy and choose foods with good nutrition. The FDA’s theme for 2012 is “Remember to Use the Nutrition Facts Label.” One tool you can use to help make good food choices is the Nutrition Facts label that appears on all packaged foods and beverages. To learn how to read labels, visit the FDA’s web page “Nutrition Facts Label Programs and Materials.”
One Shot One Kill: Want to learn how the elite warrior accomplishes optimal performance time after time, under the most challenging conditions? The HPRC now has new program materials for the One Shot One Kill (OSOK) performance enhancement program online for you to use and download—by yourself or with your unit! One Shot One Kill (Integrative Platform version) is a “warrior-centric” performance enhancement program that warriors can set up and manage on their own. OSOK-IP is designed to enhance performance, hardiness, and resilience. By building on the skills that Warfighters already possess, OSOK aims to translate good Warfighter qualities to outstanding ones. OSOK-IP comes in two versions:
OSOK-IP Solo is a step-by-step integrative training plan, with supplemental materials, that enables the individual Warfighter to pursue this method of Total Fitness on his or her own and reach the optimal level of performance in almost all areas of life.
OSOK-IP Train the Trainer enables your unit to train as a group by selecting one member to learn and present OSOK-IP to the rest of the unit. This section of the website has the full curriculum available to download and even customize OSOK-IP content for your own military culture and unit.
We look forward to your feedback, too. Check out OSOK and let us know what you think!
If you exercise in the cold, consider these tips from the American Council of Exercise (ACE; Exercising in the Cold) to stay safe. Check how cold it is before you go out, and do not exercise if the conditions are too extreme. Be sure to dress warmly (keep your head, hands, and feet warm) and dress in layers that can trap insulating dry air near your skin. In addition, avoid blowing air into your gloves and mittens because it will add moisture, which will cause your hands to be colder. For more detailed information, you can read the original American College of Sports Medicine position stand: prevention of cold injuries during exercise.
The ArmyTimes reported that due to this summer’s excessive heat wave, which affected most of the United States, the Army’s physical training has been impacted by two heat-related deaths and several cases of soldiers who became ill in the heat and sought medical treatment for heat injuries. According to the article, Army officials are looking for better ways to handle the heat and keep soldiers from succumbing to it.
Heat injuries can be a cause of both illness and fatalities. The Environment: Heat section of HPRC’s website provides valuable information on policies, reports, and guidelines for surviving and performing in hot environments.
With hot, humid conditions expected to last through the week, the Los Angeles Times featured an article that explains how the body senses life-threatening danger and starts fighting to keep cool when the temperature rises in extreme heat conditions. Those at highest risk include people over age 60 and those who are overweight or have heart disease, diabetes, or respiratory problems. Being aware of the symptoms of heat illness and taking preventive measures to stay cool and hydrated are the keys to protecting against heat-related illness.
Warfighters are deployed to all kinds of environments, including hot and dry conditions where sun exposure is a concern. Choosing a "broad-spectrum" product that protects against sunburn, skin cancer, and premature skin aging is important, but product labeling can be confusing. Now, however, the Food and Drug Administration (FDA) is taking steps to regulate the labeling of sunscreen products in order to help consumers choose a product that will protect them from sun damage to the skin.
The new measures include a regulation, effective one year from now, that requires sunscreens to undergo a standard test if they want to be labeled as a “broad spectrum” product. Those that pass the test will be allowed to use “broad spectrum” on their packaging, which indicates a product that provides protection against both ultraviolet B radiation (UVB) and ultraviolet A radiation (UVA). UVB rays are primarily responsible for sunburn, but both UVA and UVB rays are harmful and can cause sunburn, skin cancer, and premature skin aging.
Other provisions in the FDA regulation include:
- A warning about the risk of skin cancer and early skin aging on the labels of sunscreen products that are not broad spectrum.
- The amount of time the consumer can expect protection from a product with water resistance claims must be stated on the front label. The FDA, based on standard testing, will allow either a 40-minute or 80-minute timeframe on labels.
- Products will no longer be allowed make a claim of “waterproof” or “sweatproof” or use the term “sunblock,” nor can they make the claim of immediate or instant protection or protection for more than two hours without reapplication.
Additional measures regarding the labeling of sunscreen products have been proposed. To learn more, view the FDA’s full article.
Heat-related injuries are a threat to Warfighters, even those in top physical condition, deployed to extreme environments. Heat acclimatization is necessary to ensure that the health and performance of Warfighters is not compromised to a dangerous degree when exposed to heat stress.
Take it slow. For unacclimatized Warfighters, physical exertion should be limited in intensity and time. Allow 9-14 days of progressive heat exposure and exertion—more for less-fit Warfighters, less for more-fit Warfighters.
Don’t overdo it; don’t underdo it! Heat acclimatization requires exposure at least two hours per day (can be two one-hour segments) while engaged in a cardiovascular exercise (which should increase in intensity each day of the acclimatization period).
It’s all relative. The level of heat acclimatization achieved is relative to the exertion normally expended by the Warfighter. If light exertion is the norm, the level of heat acclimatization after two weeks will match that. If more strenuous exertion is called for, additional acclimatization and possibly improved fitness is required.
Work smart. If Warfighters must perform physical work during the acclimatization period, take advantage of the cooler hours during the morning, evening, and night.
Stay hydrated. Adequate water is essential. Heat acclimatization increases sweating and, therefore, water requirements. Dehydration rapidly degrades safety and performance, even for those who are already heat acclimatized or in top physical condition.
For a more detailed look at heat stress and acclimatization, read HPRC’s reports on managing heat exposure.
Research at USARIEM (U.S. Army Research Institute of Environmental Medicine) was featured in a article by writer Christopher Solomon titled "G.I. Joe and the House of Pain" in a special issue of Outside Magazine about human performance. The author spent time in the research lab's heat chamber, altitude chamber, and cold-water pool—conditions that simulate the extreme environmental conditions found in theater. He interviewed research physiologists there about USARIEM's work over the past 50 years as well as its current studies, all of which address the crucial issues of Warfighter health and performance in extreme environments.