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Noise pollution and hearing loss

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Helicopter propellers, jet engines, explosions, moving vehicles, gunfire, and more—all sources of noise pollution that troops may experience in the line of duty—can affect your hearing.

Noise-related hearing loss is a tactical risk for individual warriors and unit effectiveness. Being able to hear well is crucial for effective communication and—perhaps more important—for survival. While the military has done extensive research and established standards regarding noise and noise exposure, there are a few things you can do to help minimize your risk of this occupational hazard.

  • Wear hearing protectors when firing weapons or traveling in noisy vehicles or aircraft.
  • Make sure that earplugs such combat arms earplugs (CAE) fit properly to protect your hearing but still communicate effectively.
  • Replace lost or damaged hearing protectors as soon as possible.
  • Limit exposure to “annoying noise” during normal daily activities. Trying to ignore noise can increase your heart rate and blood pressure and cause sleep problems and other negative health effects.
  • Report any signs of hearing loss as soon as possible.

Hearing loss, including tinnitus, has become an "invisible" injury and an accepted outcome of military service. Blast injuries from improvised explosive devices (IEDs), RPGs, and mortar rounds are the largest cause of hearing loss for forces in Iraq. Compensation payments for hearing loss as the primary disability increased 319% between 2001 and 2006. While there is currently no cure for tinnitus, there are treatments available.

The DoD Hearing Center of Excellence is committed to preventing, treating, and rehabilitating hearing loss and auditory injury for service members and veterans. HCE offers evidence-based clinical care in collaboration with other organizations and Centers of Excellence to improve quality of life for hearing-impaired service members and raise awareness about noise pollution and occupational safety.

Noise pollution may be an inevitable part of serving in the military, but it doesn’t have to leave you with a permanent reminder. Do what you can to help hold on to your hearing.

Don’t get “computer eyes”

Take regular breaks and adjust your computer environment to prevent eye strain and enhance performance.

Sitting in front of a computer for hours can make your eyes tired, and your visual performance can suffer. To help with potential negative effects, create an environment that has equal brightness everywhere around your computer screen. Try these tips to help:

  • Reduce intense fluorescent lights.
  • Turn on some lights if you usually look at computer screens in the dark.
  • Dim excess light coming through windows with blinds, tinting, or window covers.
  • Avoid glare on your computer screen.
  • Take microbreaks to look at distant objects.

If you’re in an office environment, if possible, turn off overhead lights and have a table lamp for softer light. If you can’t control the lighting in your environment, there are screens you can place on top of your computer screen to reduce glare. In a previous article, we highlighted how 30-second microbreaks every 20 minutes can ease physical discomfort and improve mental performance when working in front of a computer. Similar breaks also help reduce eye strain. Experts suggest looking at a distant object at least twice every hour to help prevent visual fatigue. So if you take a break every 20 minutes for brief stretching, make sure it also includes looking at a distant object to help both your eyes and body. 

“Winter is coming...”

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Filed under: Cold, Environment, Winter
Well, winter may actually already be here, depending where you are, so make sure you’re prepared in case of a winter weather emergency.

Winter’s not over yet. The next month or more can bring anything from ice and sleet to “Snowmageddons” and polar vortexes. Winter weather can be dangerous for you, your family, and even your pets if you’re not prepared. In the event of an emergency you should know what to do to protect yourself and your loved ones. The National Center for Disaster Medicine and Public Health has compiled a list of resources that offer information, tips, and checklists for winter-weather emergencies and general cold-weather health. Stay warm, safe, and resilient!

Prepare to “fall back” gently

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Daylight Savings Time changes to Standard Time the first weekend in November! Be ready with a plan to stay fit despite darker mornings and evenings.

Getting an extra hour of sleep is a dream come true for many of us. For others, the end of Daylight Savings Time means an extra hour on the town or time to catch up on a to-do list. No matter how you choose to spend your extra hour, the amount of sunlight typically decreases over the following weeks, depending on where you are in the world. The change in daylight may influence your outdoors activities, so take this time to make a plan for how to remain active in the upcoming “dark days” of Standard Time.

Plan ahead for outdoor activities in the dark:

  • If you jog or hike outdoors in the morning or evening hours, wear reflective or light-colored clothing to be easily visible.
  • Plan your route ahead of time and let someone know when and where you will be exercising.
  • Have a cell phone handy in case of emergencies.
  • Be vigilant. A head-mounted flashlight can help you see holes and debris in your path to avoid sprains and injuries. Also beware of animals that might spook as you pass them in the dark.
  • If you must wear earphones, only use one ear bud.
  • Bring a buddy or pet!

Plan fun activities indoors:

  • Move your exercise routine indoors. Whether in the gym or at home, there are plenty of ways to stay active. Try High Intensity Tactical Training (HITT) for a vigorous workout. Or take this time to give yoga a try or deepen your practice.
  • Plan activities that get the entire family involved. Even if you don’t have a gaming console, you can try dancing, hula hoop, or a jump-rope contest. HPRC has more family fitness ideas you can try.
  • Finally, think about how much sleep you usually get. Do you get the recommended seven to eight hours every night? This extra hour might be the jumpstart you need to begin prioritizing sleep. For more information on sleep tips, check out HPRC’s Sleep Optimization section.

Why did the Chikungunya cross the road?

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Cases of a mosquito-borne virus, new to the western hemisphere, have been reported in the Caribbean and recently in the U.S. Read more about this virus, where it came from and how to avoid being exposed.

West Nile. Dengue. Malaria. Chikungunya. No, that’s not a typo. Chikungunya (pronounced “chik-en-gun-ye”), a mosquito-borne virus that primarily occurs in Africa, Asia, and the Indian subcontinent, and Warfighters deployed to these regions have been exposed to this risk for some time, now, however, it is reportedly spreading to Europe and the Americas. Most of the cases in the U.S. involve individuals who have recently traveled abroad, but the Centers for Disease Control and Prevention (CDC) just reported the first locally acquired case, in Florida.

The viral illness is characterized by fever and severe joint pain, but other symptoms include headache, muscle pain, joint swelling, and rash. There is currently no antiviral drug for Chikungunya, and treatment is aimed at relieving symptoms. Most patients will recover fully on their own, although sometimes symptoms persist for several months.

It’s important to know your environment. If you’re being deployed to these regions or even going there on vacation, there are things you can do to protect yourself from mosquito bites and mosquito-borne infections. Wearing long pants, shirts with long sleeves, and insect repellent while outdoors reduces the chance of an insect bite. Other precautions include removing standing water from containers such as flowerpots and buckets and placing screens over open windows and doors.

If you think you could have been infected, you should see your doctor, especially if you have recently traveled to high-risk regions. Visit the Center for Disease Control (CDC) for more information about Chikungunya.

How does air pollution affect physical performance?

It is known that exposure to air pollutants during exercise may affect your health and performance, but what can you do about it?

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.

Colds versus allergies

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Can you tell the difference between a contagious cold and the irritating allergies that affect some people in the spring?

Have you been experiencing symptoms such as sneezing; a runny nose; watery and/or itchy eyes, and fatigue? Colds and allergies both can make you feel miserable and affect your performance, but it can be hard sometimes to tell which is which. The causes of each are distinctly different: Colds are contagious, and they are caused by viruses. But allergies are due to sensitivity to allergens such as seasonal pollen, and they’re not contagious. To prevent colds, hand washing is key, along with hygiene etiquette such as covering your mouth or nose when you cough or sneeze. To avert allergies, on the other hand, try to avoid the allergens that cause your symptoms. Common allergens, especially in the spring, include grass and tree pollen. Year-round allergens include mold, animal dander, and dust mites. It can be a challenge to exercise and enjoy the outdoors if you have allergies, but it’s not impossible. Here are some tips to help you manage your allergies:

  • Know and avoid your allergy triggers. If you’re not sure what you might be allergic to, getting tests done by a specialist could help you narrow it down. A doctor might also suggest an antihistamine or inhaler to help prevent flare-ups.
  • Check the air quality in your area every day. If the pollen count is high, avoid spending too much time outside, mowing the grass, or exercising outdoors.
  • Shower after being outside. This can help reduce symptoms by washing pollen off your, skin, hair, and eyelashes.
  • If you must be outside during high pollen/pollutant times, wear a cover (such as a mask or bandana) over your mouth and nose to keep particles out of your airways.
  • Rinse out your nose with a saline spray to help wash away allergens after being outside.

Sub terra firma

Combat training is moving underground. New tactics—and, potentially, new doctrine—are being developed to help troops perform in underground environments where enemies could hide.

The U.S. Army’s Asymmetric Warfare Group has been training joint forces in some unusual places—underground venues such as tunnels, caves, and sewers. As battlefields become more urban and enemies move underground, subterranean environments pose unique operational challenges. Although the Army does not currently have an official field manual for underground combat, this new tactical training has developed units’ ability to perform in these environments. Combat training centers are starting to integrate these kinds of complex environments into their facilities, and the Army is urging home-station training to “get creative” and use simple techniques to simulate their own underground environments. Something as simple as training in a dark room with obstacles can simulate underground areas. Israeli Defense Forces have also had success with this type of training. Being able to adapt and perform in challenging environments is a vital part of warrior resilience.

Is wicking apparel as “cool” as you think?

Clothing made from synthetic material is still popular in the sports apparel industry, with many manufacturers claiming that it improves heat regulation. That’s not what the science says, though.

Walk into any fitness center on base or take note of a group of soldiers training, and you’ll probably notice at least a few people in form-fitting synthetic t-shirts. The sports apparel industry has exploded in popularity over the past decade, with numerous manufacturers now competing to develop, market, and sell the newest pieces of clothing (shirts, shorts, underwear, socks), all geared to keep athletes cool while competing or training in hot environments. Is there any science behind these claims? Does tight-fitting clothing made of “high-tech” materials actually help with heat regulation and enhance athletic performance?

You heat up when you exercise, and sweating is the primary method your body uses to stay cool. Sweat evaporating off your skin is the most important method your body has to cool itself during exercise. High-tech materials are supposed to enhance “wicking”—the delivery of sweat away from the skin surface toward the clothing, which allows for evaporation—and limit the absorption of sweat by the clothing itself. Cotton, by contrast, absorbs moisture, so it’s not considered a good choice for exercise.

To date, there’s no evidence that this high-tech clothing improves thermoregulation when worn during exercise in hot environments. Specifically, researchers found no differences in heart rate or body and skin temperatures when subjects performed repeated 20–30 minute bouts of running outfitted in shorts, sneakers, and either a form-fitting compression or traditional cotton t-shirt. Research has also found that wicking sportswear had no effect on cooling when worn under a bulletproof vest or on a cycling sprint when worn under full ice hockey protective equipment. As of now, the best advice for staying cool during exercise in the heat is to wear lightweight clothing, stay properly hydrated, and listen to your body for signs of potential heat illness. For more information on performing in hot environments, please visit the “Heat” section of HPRC’s Environment domain.

Risks of activity at altitude

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Altitude affects what your body needs and how it responds, especially when it comes to exercise.

Performing physical activity—whether exercise or mission demands—at moderate (4,000–7,900 ft or 1,200–2,400 m) and high (7,900–13,000 ft or 2,400–4,000 m) altitudes can be challenging. At high altitude, oxygen pressure is lower, which results in less oxygen in the blood and muscle tissues. And as altitude increases, there’s a decrease in air temperature (about 2°F for every 500 ft or 150 m), less moisture (resulting in drier air), and increased solar radiation. Use sunscreen, drink plenty of water, and watch out for the signs of acute mountain sickness: headache, nausea, shortness of breath, and impaired cognition and balance.

To learn more about altitude sickness, read the article “The Invisible Enemy of the Afghanistan Mountains” on the United States Army Research Institute of Environmental Medicine (USARIEM) website. And learn more about performance at altitude in the Altitude section of HPRC's Environment domain.

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