Filed under: Op-Ed
Sweat is a critical function when you’re performing in hot environments. As your body absorbs heat from the environment, your nervous system activates sweat glands to release sweat. The moisture on your skin then evaporates, taking heat away from your body and cooling you off.
Protective clothing impedes the evaporation of sweat and the heat exchange between you and the environment, a condition known as “evaporative resistance.” This means that the exposed parts of your body will cool off more quickly than the parts that are covered, but they are also more prone to insect bites. Reports from Marines and National Park employees feeling “excessive heat” and a loss of sweating sensations after applying moderate to high amounts of DEET to their skin brought the safety of this insect repellent into question.
In a recent study, researchers found that when 33% DEET lotion is applied according to military protocol, it does not interfere with sweat production or other physiological responses. Nor does it interfere with the evaporation process necessary for cooling to take place. Researchers concluded that 33% DEET can be worn safely during military and occupational activities performed in hot, insect-infested environments. Similar studies have found oil- or alcohol-based repellents may increase core temperature by reducing sweat evaporation rate but do not affect sweat production. The military-approved form of DEET is polymer-based.
You can watch a YouTube video about the science behind the study.
DEET is considered by the EPA to be a toxic pesticide. It should be used with caution and as directed. More information about DEET, its uses, and warnings can be found on the EPA fact sheet. As of 2004, DEET was considered safe for use on children older than two months of age. Specific information on its use and effect on children can be found in the EPA TEACH chemical summary.
Motion sickness can affect even the strongest Warfighters. Nausea, vomiting, dizziness, and sweating are some of the telltale signs of kinetosis, or motion sickness. The potential impact on individual and force readiness make it a concern in military medicine.
Motion sickness may affect individuals differently, but generally it follows a pattern. The earliest symptom typically is abdominal discomfort. If the motion continues, discomfort is usually followed by overly warm sensations, nausea, and wanting cool air.
Motion sickness can be alleviated to a degree by following these simple tips:
- Pick a seat where motion is less likely to be felt, such as an aisle seat on a plane, a central cabin on a ship, or a car toward the front of a train.
- Avoid sudden movements of the head, which can aggravate motion sickness.
- Avoid tasks that involve prolonged close-up eye movement or focus (such as reading a book). Focus instead on the road in front of you or on a distant object so that your senses can confirm that you’re on the move.
- Avoid alcoholic beverages before and during a trip, as alcohol can worsen motion sickness.
- If possible, expose yourself to the motion in gradually and in stages until you adapt to the movement.
Jerome Greer Chandler, a former combat medic, describes the severity of motion sickness among U.S. service members in an article to The American Legion Magazine [PDF]. For a detailed reading on motion sickness and its effect among military personnel, see the Textbooks of Military Medicine (volume 2).
Yoga’s popularity is growing in the United States, but many Americans are still not familiar with the details of this ancient practice. Yoga roots are holistic in nature—body and mind are of equal importance, and the asanas, or poses, which define yoga for many of us, are only one aspect of practice. Together with meditation and breath control, yoga promotes strength, flexibility, and awareness of body and mind. Yoga can help achieve wellness through meditation, deep relaxation, stretching, and breathing. Several organizations are now beginning to provide yoga classes tailored to veterans and active-duty service members who suffer from combat stress. VA facilities, Warrior Transition Units, and civilian studios are using it to complement traditional treatment of patients with post-traumatic stress disorder and traumatic brain injury.
Individuals who struggle with PTSD describe it as a feeling of disconnectedness from themselves and others. Yoga, which means “bringing together parts as a whole,” helps people feel connected again. One traditional type of yoga that has been shown to decrease anxiety in the military population is sensory-enhanced hatha yoga, which involves breathing, meditation, and certain poses. A specific benefit reported by participants in sensory-enhanced yoga was a decrease in insomnia. Combat-stressed adults also experienced reduced hyperarousal symptoms such as anxiety, depression, and rage. Integrative Restoration (iRest) is a yoga-based meditative practice that teaches a person to focus on breathing when a negative memory arises. Soldiers and marines have expressed satisfaction in these breathing techniques because of the method’s simplicity and ease. It allows a person to regain control over his/her thoughts whenever symptoms of PTSD present themselves. A study found that iRest decreases rage, anxiety, and emotional reactivity all of which encourage negative thoughts and memories. Those practicing iRest also reported increased feelings of relaxation, peace, self-awareness, and self-efficacy. Walter Reed Army Medical Center (WRAMC) was one of the first military facilities to research the outcomes of yoga for veterans and active-duty warriors suffering from PTSD. WRAMC immediately added iRest to its weekly treatment programs for soldiers suffering from PTSD and TBI after observing its effects: increased calm and peaceful feelings, less severe reactions to situations, and increased outlook on life.
There are many more yoga practices than the ones mentioned here, and each yoga method is different, so you can find the right one for you!
Preparation for the PFT/PRT takes time and discipline. Training for the test should not be something you start the week prior, and the habits you begin leading up to the test should be ones you continue after the test. Weekend warriors and procrastinators are at greater risk for injury, and it’s likely that performance will be less than optimal when it comes time for PFT/PRT. If you’re just getting back into shape, be sure to do it gradually. Once you’ve resumed a regular exercise routine you may notice aches and pains associated with getting back in shape. Listen to your body. Be vigilant for symptoms of overuse injuries and knee pain, which are common athletic injuries. It’s important to address these issues early to minimize any damage and get you back in action as soon as possible. Maintaining your exercise routine after the PFT/PRT and challenging yourself along the way will keep you in soldier-athlete shape year round, and prevent deconditioning. Check back to past articles on cardiovascular, muscular and mobility fitness for guidelines and tips.
Your body is a segmented, or jointed, system designed for potentially powerful and efficient movement. Coordinated and efficient movements require a give and take between mobility and stability of the involved joints, as well as the surrounding muscles, tendons, and ligaments. These components, together with muscular fitness, are necessary to achieve functional movement, which is integral in performance and sport related skills.
According to the American Council on Exercise (ACE), joint mobility—also known as range of motion (ROM)—is the degree to which a joint is able to move before it is restricted by surrounding ligaments, muscles, and tendons. Joint stability is the ability to control or restrict joint movement through the coupled actions of surrounding tissues. Preventing injuries requires, among other things, both mobility and stability of your musculoskeletal system. Deficiencies in one or the other, due to improper or imbalanced training, may lead to injuries during movement patterns, such as walking, running, and repetitive lifting.
One example of an elite training program is the Army Ranger RAW functional fitness program. It is unique in that it focuses on whole-body mobility and stability. Exercises are typically performed using your own body weight against fixed surfaces (i.e. the floor or wall), instead of using free weights or machine weights.
For joint stability and balance, the National Academy of Sports Medicine (NASM) recommends performing one to three sets of 12-20 repetitions at a slow, controlled pace. According to American College of Sports Medicine (ACSM), there is not enough research to make definitive recommendations on the frequency and duration for this type of training. However some research has shown improvements using training frequencies of 2-3 days per week, with sessions lasting ≥20-30 minutes, for a total of ≥60 minutes per week.
The amount of joint mobility is partially determined by the flexibility of the surrounding muscles, tendons, and ligaments. For example, decreased shoulder flexibility might impact your ability to complete a full pushup. Refer to these FITT guidelines for flexibility training.
Frequency: According to ACSM, short-term improvements in flexibility may be seen after each bout of stretching. More long-term changes, however, are seen after three to four weeks of regular stretching. Flexibility exercises should be performed at least two to three days per week, but daily exercise will improve range of motion.
Intensity: ACSM also recommends that flexibility exercises should involve major muscle groups (neck shoulders, upper and lower body), stretching to the point of slight discomfort within the range of motion, but no further. You should feel slight tension in the muscle, but it should not be painful.
Type: There are several different types of stretches:
• Static stretching slowly elongates a muscle by holding the position for a period of time.
• Dynamic stretching is usually sport specific. It requires a joint to be stretched through its full range of motion, to lengthen and increase the muscles temperature.
• Ballistic stretching is a type of dynamic stretch where the muscle is forcefully elongated through a bouncing motion. There’s no evidence that ballistic stretching results in injury, but there is still question and ongoing research as to whether this technique affects muscular performance.
• Proprioceptive Neuromuscular Facilitation or PNF stretching may produce greater gains in ROM, however, it may be less practical since an experienced partner is needed to perform this type of exercise.
Time: Your stretching routine should take about ten minutes or so to complete. Static stretches should be held for 15-20 seconds, while PNF stretches should involve a six-second contraction followed by a 10- to 30-second assisted stretch.
Use caution when working on mobility and stability exercises. Done properly, these exercises should not cause pain in the joint or muscle. Never push through your threshold, have patience, and treat your joints with care.
Armed Forces Day was created in 1949 to honor Americans serving in the military. In 1962 President Kennedy established it as an official holiday on the third Saturday in May. Why should Armed Forces Day get attention on a DoD human performance optimization website? As director of HPRC, I think this holiday has the potential not just to honor the Armed Forces but for the Armed Forces to do what it has done many times in the past: respond to a crisis for the United States. The Armed Forces go to war to support a political strategy, and no national strategy at the present time is more critical than the war on obesity and tobacco. DoD has chosen these as part of the National Prevention Strategy. So how do we fight this war? We the military can start by setting the example for the rest of the country by bringing into our homes the practices of physical fitness and good nutrition as well as a smoke-free environment. We can make fitness and nutrition a priority for our spouses and children. We can make fitness and nutrition family activities that can promote good health, form stronger families, and make family members happier, closer together, and more productive. The military family can be the model for the civilian community to copy—a family working together toward a common goal of health and fitness. The payoff is tremendous in the present and the future. The military can be the beginning of a movement across the country to fight and win the war on obesity and tobacco use. The HPRC website has lots of helpful information in this war on obesity and tobacco. Check out the site (www.hprconline.org) and look under Physical Fitness, Nutrition, tobacco (under Mind Tactics Performance Degraders), and Family & Relationships. There is much that can be done. Join the war on obesity and tobacco. Set an example in your community for healthy living. Oorah! Hooah!
In training, in the field, and even when you’re not thinking about it—such as moving ammunition boxes into a transport—your muscular strength and endurance are essential components of your overall fitness. But training to improve muscular strength is not the same as training for muscular endurance. Muscular strength is the amount of force that a muscle can produce with a single maximum effort. Muscular endurance is the ability to sustain a muscle contraction over a period of time, or to repeatedly contract a muscle over a period of time.
When applying the FITT principle to your muscular fitness routine, here are some guidelines to follow:
Frequency. According to the most recent guidelines set forth by The American College of Sports Medicine and in agreement with other military fitness programs, resistance training for muscular fitness—both strength and endurance—by the “whole-body” training approach should be performed two to three days per week with at least 48-72 hours of rest between training sessions. The “split-body” approach involves focusing on one set of muscle groups one day and a different set on another day. This allows for consecutive days of resistance training in a cyclical routine. For example, you might exercise upper body muscles one day, followed by lower body muscles the next, and core/back muscles the third day of the rotation. Cycles in the split body approach will vary depending on how many muscle groups are exercised per day.
Intensity. With consistent training of two to four sets of reps per muscle group, most people see an increase in the size and strength of their muscles. However, even one set can result in improvements, especially in novice exercisers. When training for muscular strength, the weight you use should be about 60-80% of your one-repetition maximum (1RM). If you’re new to weightlifting or have not lifted weights for a while, start at 60%. (See our Healthy Tip on how to determine your 1RM.) For muscular strength, aim for eight to 12 reps per set, with a two- to three-minute rest between sets. If your objective is to improve your muscular endurance, the recommendation is 15-25 repetitions at no more than 50% of your 1RM, with a two- to three-minute rest between no more than two sets. A well-rounded muscular fitness program should include both strength and endurance training, but consider your specific goals when deciding on your approach.
Type. There’s a lot of different equipment you can use for resistance training, including machines with stacked weights, free weights, and resistance bands. Some exercises don’t require equipment, just your own body weight. For example, pushups and sit-ups, as assessed in the PRT, will help improve your muscular endurance. Individual exercises should focus on the major muscle groups such as the chest, shoulders, upper and lower back, abdomen, hips, thighs, and calves. Read more about the advantages and disadvantages of different types of training equipment, and about workouts that utilize your own body weight or minimal equipment.
Time. The duration of a resistance-training workout can vary considerably and is less important than maintaining proper form and technique. As for the tempo of each exercise, The American Council on Exercise (ACE) recommends lifting the weight for a count of two seconds, and lowering for a count of three to four.
Progression. According to ACE, once you are able to perform the maximum number of repetitions correctly and with relative ease, increase the amount of resistance by five to 10%. This applies to repetitions performed for both strength and endurance.
Minimize the risk of injuries by using proper form, exercising with a partner, and paying attention to signs of excessive fatigue and pain. And if you’re new to resistance training, consult a certified personal trainer on proper lifting techniques.
The next Op-Ed in this series will discuss mobility training for the PRT.
Memorial Day began as “Decoration Day” after the Civil War. In 1882, Decoration Day became widely known as Memorial Day, and after WWII it became a day to remember all our fallen heroes, not just those from the Civil War. In 1967, Congress passed the law making it an official holiday to be celebrated on May 30, subsequently changed to the last Monday of May. We at HPRC extend our greatest appreciation to those who have perished for our nation and offer our sincere sympathy for the families left behind. There are many ways people choose to remember those who gave their life as a supreme sacrifice to our country and its ideals, but most involve outdoor activities with families. HPRC (www.hprconline.org) is dedicated to providing our Warfighters and their families the information they need to build their resilience to prevent injury and illness and carry out their missions as safely and effectively as possible. Our desire is to reduce the level of sacrifice our warriors have to make as they fulfill their future missions for us and for our Nation.
The American Academy of Orthopaedic Surgeons defines a stress fracture as a tiny crack in a bone that occurs when fatigued muscles lose their ability to absorb shock and then transfer stresses to the bone. Most stress fractures occur in the lower extremities, and more than half occur in the lower leg and foot.
A stress fracture is an overuse—sometimes referred to as chronic—injury, which means that it develops over a long period of time—from weeks to months. According to a 2011 systematic review published in Military Medicine, stress fracture incidence is high among U.S. military recruits, ranging anywhere from 3% for men to 9.2% for women.
Since it can take several weeks or months for a stress fracture to heal, the best approach is to avoid getting one. Here are some tips for prevention:
- Apply the progression principle of training—gradually increase your training intensity. Slowly incorporate higher-stress activities such as jumping and interval training into your workout. Setting incremental goals can be helpful in carrying out your training routine in a gradual way. And check out HPRC’s Physical Fitness Resources for more information on training and ways to avoid injury.
- Check your footwear and make sure it matches your training. Replace footwear that is old or worn.
- Pay attention to the surface where you train, since some are easier on the bones and joints of the lower extremities. For example, it is better to jog on softer surfaces such as rubber track or grass rather than on concrete. Also, it’s better to begin training on a flat surface and then progress to hills.
- Monitor your diet, specifically calcium and vitamin D intake, and read the National Institute of Health’s Dietary Supplement Fact Sheet on calcium. To learn more about nutrition take a look at HPRC’s Nutrition Resources.
HPRC has received a number of questions about whether dietary supplements—especially those used for bodybuilding and weight loss—could result in a positive result on military drug tests.
Military drug testing begins with urine, which is first screened and then followed by additional tests depending on the outcome of the screen. You can get extensive information about the DoD drug policy and drug testing from the TRICARE website section on the Drug Demand Reduction Program (DDRP), including military testing. And for answers about the potential effects of specific dietary supplements on drug screening tests, you can contact your service’s military drug testing laboratory by phone or email at:
- U.S. Army, Fort Meade, MD – (301)-677-7085 FTDTL_MSupport@amedd.army.mil
- U.S. Army, Tripler AMC, HI – (808)-433-5176 FTDTLWeb.Portal@amedd.army.mil
- U.S. Navy, Great Lakes, IL – 847-688-2045, press 2 or ext 113 NDSLGLemail@example.com
- U.S. Navy, San Diego, CA – 619-532-5180 NDSLSDfirstname.lastname@example.org
- U.S. Navy, Jacksonville, FL – 904-542-7755, press 2 or ext 104 DLJAX@dlj0ndsl.med.navy.mil
- U.S. Air Force, Lackland AFB, TX – (210) 292-3089 email@example.com
Positive urinalysis results due to dietary supplement use can occur because products on the market may contain undeclared drug ingredients—that is, controlled substances that are not stated/listed on the product label. More information can be found in the FDA News Release from 2010 in which this was brought to the public’s attention. There is no way to know if a particular supplement contains an undeclared drug without laboratory testing, but the FDA does keep track of such products once identified through its MedWatch program. One of the best ways to check for such products—and other potential health issues related to dietary supplements—is through the FDA website’s Dietary Supplements Alerts section.
The Department of Defense (DoD) currently has no formal policy on the use of dietary supplements and no list of either banned or safe supplements. For more on this topic, read HPRC’s article “Is there a list of dietary supplements/substances banned by the military?”