Welcome to the HPRC Blog. We've got lots of information here, from quick tips to in-depth posts about detailed human performance optimization topics.
HPRC Fitness Arena: Environment
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.
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.
With current and future military operations in mountainous regions, the issue of acute mountain sickness (AMS) is a significant medical concern. AMS can affect anyone, military or civilian, who is unacclimatized and/or ascends too rapidly to high altitudes. Symptoms of AMS can include headache, nausea, fatigue, dizziness, and sleep disturbances. Recently, researchers at USARIEM were able to predict the severity and prevalence of AMS after rapid ascent to various altitudes. What they found was that for every thousand-meter increase in elevation over 2,000 m, a person was over four times more likely to develop AMS. In addition, the severity of sickness doubled, and the odds that the AMS would worsen increased almost five-fold. AMS appeared to peak at 18 to 22 hours of exposure to altitude and then went away after 42 to 48 hours. The severity of sickness is greatest above 4,000 meters and may require evacuation to lower altitude or immediate medical attention. It also appears that men are more likely than women to get AMS and more likely for it to be severe. For both men and women, the more active they were at altitude, the longer it took to recover. These findings support current recommendation to limit activity as much as possible in the first 24 hours at altitude to decrease the risk for AMS.
This information should help military leaders manage and perhaps prevent AMS among troops by knowing the elevation, types of activities, and lengths of stay at altitudes.
In order to reduce the risk for AMS, acclimate to moderate elevations (2,000 – 3,000 m) if/when possible. In addition, stay hydrated and try to limit your physical activity at altitude for the first 24 hours. Read more about the effects of altitude on performance and how to minimize your risk for AMS.
Giant hogweed—no, it’s not an ingredient in one of Harry Potter’s potions; it’s a large poisonous plant that started to bloom in the northeast and northwest areas of the U.S. and parts of Canada earlier this month. If you’re out for a ruck march through the woods and you come across this plant, do not touch it. The sap can cause irritation and burns to your skin and perhaps blindness if it gets into your eyes. If you do happen to come in contact with it, be sure to wash your skin with soap and water and keep the area out of the sunlight for 48 hours. Giant hogweed can grow 14 feet or higher. It’s characterized by large leaves and white, umbrella-shaped flower clusters at the top of the plant. It may be difficult to distinguish from other non-poisonous plants such as cow parsnip, so err on the side of safety if you’re not sure. You can read more about identifying invasive species in your area from the U.S. Department of Agriculture.
Your sunscreen has an expiration date—have you checked it lately? It’s meant to last up to about three years; after that, the active ingredients start to deteriorate, making it less effective and leaving you vulnerable to sunburn and sun damage. Ideally, you should be using your sunscreen often enough that a bottle doesn’t last through the summer. If that’s not the case, check the bottle you’re currently using—if it’s old, throw it out. If you buy sunscreen that has the expiration printed only on the box or wrapper, write the date somewhere on the bottle itself with a permanent marker. Practice safe sun this summer to keep you and your family healthy and happy!
Lyme disease is a serious concern for those who spend a lot of time in heavily wooded areas and a especially for the DoD. It’s common in the United States and around the world and is caught from the bite of two different species of ticks—the deer tick and the western blacklegged tick.
After spending time in wooded or grassy areas, check yourself all over, including your back (enlist a friend or a mirror to help). The early removal of a tick that’s attached to you is key in preventing Lyme, since the tick must be attached for 24-48 hours in order to transmit the bacteria that cause this disease. Ohio State University conducted a study using different tick-removal tools and concluded that all three tools were effective—and confirmed that early removal is more important than the type of tool that is used. The Centers for Disease Control provides easy-to-follow tips on tick removal using just tweezers.
If you know you’ve been bitten by a tick, or begin to notice symptoms such as a bullseye rash (an early sign of Lyme infection) at a bite location, fatigue, chills, fever, muscle aches, or swollen lymph nodes, you should to see your doctor. Blood tests can be used to confirm whether the symptoms are from Lyme disease. If left untreated, more severe symptoms can occur, such as loss of muscle tone in the face (called Bell’s palsy), severe or shooting pain, and heart palpitations. A typical successful treatment includes a course of antibiotics, but there can still be lingering symptoms, called chronic or post-treatment Lyme disease syndrome. When it comes to Lyme disease, the best offense is a good defense. Some tips for prevention:
- Wear your military uniform properly. This can help to prevent tick bites since long pants, long sleeves, and pants that are tucked into boots minimize exposed skin.
- Use insect repellents such as DEET or Permethrin.
- If you are in a wooded area, avoid tall grasses and brush. If this isn’t possible then be sure to follow tips #4–7 below as you are able.
- Perform a thorough skin check—especially of the hair and base of the skull at the hairline.
- Shower within two hours of being outside. This can help wash off ticks that are still crawling on the skin.
- Examine gear and pets for hitchhiking ticks.
- If you have access to a dryer, put your clothes in it for an hour on high heat to kill any ticks.
If you are interested in more information on diseases and conditions that are spread by ticks, insects, or other pests, you can visit the Armed Forces Pest Management Board.
If you’re in the military, your smartphone may have just gotten smarter. Researchers have recently developed hardware and software that enables teams with Android smartphones to locate nearby snipers. Acoustic sensors have been developed and used by the military in the past, but this portable attachment hooks up to a smartphone and uses microphone sensors to triangulate a sniper’s location through muzzle blasts and shockwaves. Other sniper sensors have been developed, such as the helmet-mounted sensor back in 2007 that is the predecessor to this smartphone system. According to one source, the Army has plans to send soldiers to Afghanistan with smartphone technology that will allow them to communicate—even text—more effectively out in the field. As smartphones find their way into combat, this kind of technology shows great promise for the near future.
Operation Live Well is a new wellness campaign by the Department of Defense that aims to make healthy living the easy choice and the norm for service members, retirees, DoD civilians, and their families. They point out resources for how to eat better, stay physically active, quit or avoid tobacco, and stay mentally fit. The educational, outreach, and behavior-change initiatives provide tools and resources to help you learn about healthy lifestyles. You’ll also be able to develop your own personalized health plan via the Operation Live Well website soon.
A second part of Operation Live Well is their Healthy Base Initiative (HBI), which aims to help the defense community reach or maintain a healthy weight and avoid tobacco use. Scheduled for launch during the summer of 2013 at 13 military installations and DoD sites worldwide, HBI will offer a range of installation-tailored, health-related programs that will be measured for their effectiveness. The programs that are most successful will eventually be expanded to other installations.
For more information on Operation Live Well, visit militaryonesource.mil/olw.
Test dummies are commonly used in the military for training and first aid exercises. Recently, the Pentagon has been working on finding a “human surrogate” for use in testing an array of non-lethal weapons. Modern technology equips these dummies with human-like internal and external organs as well as sensors capable of gathering information about how a person might react to such weapons. Current weapons that use stimuli such as heat, pain, and noise would be tested on these dummies rather than on live human subjects, with the goal of eliminating permanent damage while optimizing effectiveness. Other information collected would help scientists continue to build better models. Non-lethal weapons are often used for crowd-control purposes, so this technology would also benefit law enforcement, which commonly uses such systems.
The purpose of the 2011 Department of Defense Health Related Behaviors Survey of Active Duty Military Personnel (HRB) is to assess the health practices of active-duty service members. Substance abuse, mental and physical health, and lifestyle choices are important matters, especially when you need to be at your best for the demands of military life. Certain areas of this study directly affect human performance, and results (as reported in the Executive Summary) show that health behaviors vary between services.
Physical Activity/Body composition
Here are some figures from the Physical Activity/Body Composition portion:
- Overall, service members have lower rates of obesity (as defined by BMI) compared to the general public.
- More than one-third of active-duty service members age 20 and older were considered to be at a healthy weight, which exceeds the Healthy People goal as well as civilian population estimates.
- 75% of active-duty members practiced moderate to vigorous physical activity in the 30 days prior to the survey, with Army and Navy personnel having the highest rates.
- Almost half of service members do strength training three or more days a week.
Physical health and fitness are key components to optimal fitness. While these numbers are encouraging, there is no doubt that a larger portion of the military should be at a healthy weight and fit enough to fight. Make fitness and weight management your priority for performance.
- Only 40% of all active-duty personnel surveyed get the recommended seven to eight hours of sleep per night.
Sleep is an important factor in recovery. Poor sleep habits can take a physical and mental toll on your health, your relationships, and your performance.
Tobacco and alcohol
One area where the military could improve is in the use of tobacco products and alcohol:
- Almost one-quarter of service members reported smoking a cigarette in the 30 days prior to taking the survey, which is higher than the civilian population and the Healthy People objective.
- Smokeless tobacco use is also prevalent in the military with 12.8% of all service members using smokeless tobacco in the month leading up to the survey.
- Rates of binge drinking were higher in the military than in the civilian population and more prevalent in the Marine Corps than in any other branch.
Tobacco in any form is detrimental to your health. If you’re thinking about quitting smoking or would like to talk to someone about your alcohol use, there are lots of resources and professionals that can help you achieve your goal.
Stress and mental health
After more than a decade of ongoing war, troops have—and will continue to experience—significant mental stress as a result of their service. In general, 5-20% of service members reported high rates of anxiety, depression, PTSD, and/or other mental health concerns.
- The most common military-related sources of stress were being away from family and friends and changes in workload but included financial problems and family members’ health problems.
- Women reported experiencing personal sources of stress more often than men did.
- Those who drank heavily were more likely to report problems with money and relationships.
Drinking, smoking, overeating, and even attempted suicide are all negative coping factors when dealing with stress. The survey found that the most effective methods of coping were planning to solve problems and talking with friends or family members. Find out how to use productive and effective methods for coping with stress and mental health.
Nutrition and dietary supplements
Being fueled to fight is an important component for anyone in the military. Proper nutrition requires consuming healthy—and avoiding bad and potentially harmful—foods and beverages.
- According to the survey, active-duty personnel eat too many unhealthy foods such as snacks, sweets, and sugary drinks and not enough of the recommended servings of fruits and vegetables.
- More than one-third of personnel reported daily dietary supplement use.
What you decide to put in your body now may affect your performance and your career later. For more information on nutrition for combat effectiveness, read Chapter 15 of the Warfighter Nutrition Guide. And make sure you know what you’re putting into your body. Dietary supplements are not subject to pre-market approval by the FDA, and there are many ingredients that may do more harm than help. You can learn more about dietary supplements at Operation Supplement Safety. And for more information about the Health Related Behavior Survey, visit TRICARE’s webpage.