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: Total Force Fitness
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 latest update of HPRC’s list of DMAA-containing dietary supplement products is now available online. Six more products have apparently been removed from the market; one has been added to the list because the fact that it contains DMAA is stated only on the product label, not on the manufacturer’s website.
Following in the wake of the Food and Drug Administration’s warning letters to manufacturers and distributors of dietary supplements containing DMAA, the Army announced that its own study on the effects of DMAA on soldiers will continue. Read about the announcement and more in the recent Stars and Stripes article. For more information about the FDA’s action, you can read HPRC’s post, which also includes a link to the FDA news release.
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.
When you begin a resistance training program, how do you know how much weight you should be lifting? Most muscular fitness programs are designed around lifting a percentage of your maximum strength.
The first step in this process is to determine what your maximum strength is. A popular technique for assessing muscular strength is the one-repetition maximum test (1RM), or the maximum amount of weight you can press once but not twice. Alternatively, multiple repetition tests can be performed as a reliable estimate of maximum strength. One study found that a five- repetition test was the most accurate, but no more than 10 reps should be used to estimate strength. This instructional video will demonstrate the ACSM protocol for a 1RM test. This protocol can also be applied to a multiple-repetition test. For example, determine the maximum amount of weight you are able to lift five times, but not six times, for a five-rep max test. If you have doubts about whether this is the right test for you, be sure to consult your doctor.
The second step is to determine what percentage of your 1RM, in weight, you should use to improve your muscular strength and endurance. Typically, improvements in muscular strength are seen when using 60-80% of your 1RM. Increased muscular endurance is achieved using about 50% of your 1RM. Read more on muscular fitness and more details on how to train for each here. Once you have assessed your maximum strength, use this conversion chart from the National Academy of Sports Medicine (NASM) to determine percentages of your 1RM.
The Food and Drug Administration (FDA) sent warning letters to manufacturers and distributors of dietary supplements containing 1,3-dimethylamylamine (DMAA) due to lack of safety evidence provided before marketing. The FDA states that information about the safety of DMAA as a dietary supplement ingredient has not been identified. For more information, see the FDA News Release and HPRC’s latest on Dietary Supplement Products Containing DMAA.
Federal food safety information from the U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) is now provided on HPRC’s Nutrition domain page via a new “widget” (app) from the U.S. Department of Health and Human Services. Recent food safety alerts and recalls are automatically displayed and updated as new recalls, etc., are added. Please see this new feature by visiting HPRC’s nutrition section.
A recent article in the New York Times looks at the combination of neuroscience and exercise. A new theory suggests that your brain, not your hormones, increases or decreases your appetite after a workout. Researchers at California Polytechnic State University studied different areas of the brain that control whether we want and like food and how these areas are affected by exercise or sitting still.
Scientists found that “responsiveness to food cues was significantly reduced after exercise.” Compared to sitting for an hour, exercisers were much less interested in food, even ice cream sundaes. The subjects in the study were in their 20s and fit enough to sustain strenuous exercise for an hour. This is in contrast to a study that found the same areas in the brain were excited in an overweight and sedentary population after exercise, causing them to want and eat more food.
While the effect is still unclear and more variables need to be tested, researchers conclude that exercise has a definite impact on how your brain responds to food.
PsychCentral’s March 2012 "Ask the Therapist" article addresses how mindfulness relates to military performance—especially important now that the military has been incorporating mindfulness tactics for enhancing Warfighter mental and physical resilience. Of particular note is a study from the Journal of Clinical Psychology that demonstrated significant improvements in PTSD symptoms, depression, etc. in veterans after completing a Mindfulness-Based Stress Reduction (MBSR) program. The article also noted other studies that showed long-term stress-reduction, well-being, and positive experiences. Simply put, acknowledging emotional pain helps you overcome it. You are then able to focus and communicate with loved ones more effectively.
If you’d like to learn more about meditation and mindfulness, check out the Mind Tactics section of the HPRC website, which contains many resources related to meditation and mindfulness, as well as resources related to mental fitness, mental toughness, and resilience.
Good cholesterol, or high-density lipoprotein (HDL), helps prevent fat and cholesterol from clogging your arteries. A higher HDL number (> 60 mg/dl of blood) is better. Low-density lipoprotein (LDL) is considered bad cholesterol. It carries cholesterol to your arteries and can cause them to become blocked. A lower LDL number (< 100 mg/dl) is better. High-LDL or low-HDL cholesterol levels are major risk factors for heart disease and stroke. Visit this American Hearth Association web page for more information.