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.
The Department of Defense (DoD) Safety Review Panel published their findings on DMAA in a recent report now available through HPRC. The Assistant Secretary of Defense for Health Affairs asked the Safety Review Panel to evaluate the safety of DMAA-containing dietary supplement products. The Panel has recommended that the sale of DMAA-containing products be prohibited in all military exchanges.
HPRC maintains a list of dietary supplement products containing DMAA and periodically updates this list. The most recent version can be found on HPRC’s website. Note that, as of the FDA announcement in April 2013, DMAA is illegal in the U.S. as an ingredient in dietary supplements. For more information, visit the OPSS FAQ about DMAA. Operation Supplement Safety (OPSS) can provide service members and their families with information to make informed decisions about dietary supplement use. For the full DoD Safety Review Panel report, see the link on HPRC's Dietary Supplements web page.
Figuring out knee pain can take some detective work, although injuries are a common cause. For example, sports-related injuries such as anterior cruciate ligament (ACL) tears and chondromalacia (also called “runner’s knee”) can cause pain and affect performance. You can help prevent such injuries by strengthening your lower leg muscles. Strengthening your hamstrings and quadriceps, which cross the knee joint, can give extra stability and support to your knees. Leg exercises such as squats, lunges, curls, and extensions will improve muscular strength and endurance in your hamstrings and quadriceps.
Weight management is also important in preventing some knee injuries. Excess body weight only adds stress to the knees during weight bearing activities, like walking, running or jumping.
Another key to prevention is listening to your body. If you feel that minor symptoms are getting worse, it might be a good time to temporarily modify your training until symptoms subside. For example, if running is part of your cardiovascular routine, consider trying a few weeks of alternate activities that are less stressful on the joints such as swimming or biking.
Grapefruit is a tropical fruit known for its lip-puckering flavor. It contains vitamin C and many other nutrients and is a regular feature at the breakfast table. Grapefruit and its extracts also show up as flavoring agents in beverages and are sometimes added to dietary supplements.
Despite its many health benefits, grapefruit can pose a risk for people taking certain drugs. That’s because grapefruit can affect the way drugs are broken down or transported in the body—potentially increasing or decreasing the drugs’ effectiveness.
If you enjoy eating grapefruit or grapefruit-containing products, be aware of potential interactions when taking medication. If you take prescription or over-the-counter drugs, ask your doctor or pharmacist if you should avoid grapefruit. This consumer update from the Food and Drug Administration has more information.
Identity theft is a serious crime that can completely disrupt your life through credit card charges and ruined credit history if the theft is not caught quickly. So, what is identity theft? It’s what happens when someone assumes your identity by using your personal information or property—typically your Social Security number or credit cards—without your permission. According to the Bureau of Justice Statistics, there are three general types of incidents:
- Unauthorized use or attempted use of existing credit cards
- Unauthorized use or attempted use of checking accounts
- Unauthorized use or attempted use of personal information to get credit cards, accounts, or loans or to commit other crimes
Homes unoccupied for extended periods may be goldmines for thieves to dig through trashcans, dumpsters, or storage areas at homes or apartment buildings for documents with useful pieces of information. Or it may be as easy as stealing a credit card from your mailbox or directly from your wallet.
When getting ready for deployments, you can place an active duty alert on your credit reports that lasts for one calendar year. For more information and tips, review the Federal Trade Commission (FTC) handout for Warfighters and their families.
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.
Regular physical activity can make you sleep better—but how close to bedtime should you exercise? While the general opinion has been that vigorous exercise within three hours of bedtime might negatively affect your sleep, new research is reexamining this belief. Some preliminary studies have found that exercise before bed (both moderate and vigorous) didn’t negatively impact sleep quality. However, more research is needed to better understand truly how exercise closer to bedtime can impact sleep. Remember—there are many factors that contribute to a good night’s sleep. Just be aware that if you exercise in the evening, it might affect how well you sleep at night. Check out HPRC’s Sleep Optimization section for additional information.
The Food and Drug Administration (FDA) has issued warning letters to 15 companies regarding illegally marketed diabetes products that are in violation of federal law. These products are either dietary supplement products or unapproved prescription drugs with claims that they “prevent and treat diabetes” and “can replace medicine in the treatment of diabetes.”
FDA is warning consumers to stop using these products since they may harmful, and their use may interfere with receiving the necessary medical treatment for diabetes. More information is provided in FDA’s “Illegally Sold Diabetes Treatments,” which includes the news release, warning letters issued, and a consumer update.
Sodium—a component of table salt—is an essential element. It helps your muscles and nerves function correctly and maintains the proper balance of your body’s fluids. However, too much sodium in your diet may increase your risk of high blood pressure, heart attack, stroke, and certain types of cancer.
The average American consumes about 3,400 milligrams (mg) of sodium every day, mostly in the form of salt. But the current Dietary Guidelines for Americans recommends that adults limit their sodium intake to just 2,300 milligrams per day—roughly the amount in one teaspoon of table salt.
The guidelines also recommend that certain “at-risk” groups limit their sodium intake to about 1,500 mg per day: adults over the age of 51, African Americans, and people who have high blood pressure, diabetes, or kidney disease.
Recently, the Institute of Medicine (IOM) looked at the evidence supporting the current recommendations regarding sodium intake. IOM concluded:
- Research supports current recommendations to reduce sodium intake to about 2,300 mg daily.
- More research is needed to support the recommendation that those “at risk” should cut back to 1,500 mg or less a day.
Bottom line? If you’re in an at-risk group, speak to your doctor or registered dietitian about whether you should reduce your salt intake. For just about everyone else: Cut back on the salt.
How? Most of the sodium Americans consume comes from processed foods—tomato sauce, soups, canned foods, bread, and prepared mixes—but it can also come from foods naturally high in sodium—cheese and some types of seafood. Also, many restaurant foods are high in sodium, but sometimes you can request low sodium items. The best way to ensure a low sodium diet is to eat whole foods such as fresh or frozen fruits and vegetables; lean, unprocessed poultry and fish; unsalted nuts; whole grains; and low-fat dairy products such as skim milk or yogurt. For more information, check out this CDC web page.
For additional information and other conclusions from the study, see the news release (which includes a link to the full study) from the National Academies.
The physical demands of military life are challenging, and if you’re not prepared, they can lead to injuries. The injury prevention series we’ll be running over the next several weeks will provide you with information and strategies for preventing some of the most common injuries: those to the knee, ankle, rotator cuff, back, iliotibial band and wrist/hand. Prevention is key: Taking time for the small stuff may have big payoff down the road. Much of what the exercises done for recovery after an injury can actually be done to prevent the injury in the first place. Stay injury-free for optimal performance! Check back soon for the first in this series.
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.