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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.

Stimulants found in weight-loss product

The weight-loss dietary supplement product Dexaprine has been found to contain undeclared active substances and has been removed from the Dutch market. Consumers should be aware of the reports of adverse events.

Last summer the Netherlands removed the weight-loss dietary supplement product Dexaprine from the market due to reports of serious adverse events, but the results of research into the cause has just been released. A recent article in Drug Testing and Analysis described at least 26 cases of Dexaprine toxicity reported to the Dutch Poisons Information Center. Testing revealed the existence of “a cocktail of synthetic stimulants” including synephrine, oxilofrine, deternol, yohimbine, caffeine, and theophylline, and possibly ß-methyl-ß-phenylethylamines. (Problematic forms of phenylethylamines, including ß-methylphenylethylamine. were discussed in an April 2014 article in the New England Journal of Medicine.) For more information about tainted weight-loss dietary supplements, see the Food and Drug Administration’s information. Note that this product is still available in the U.S. and online.

Revisiting DMAA

Products with DMAA are disappearing quickly since the April 2013 announcement by FDA that DMAA is illegal, but some are still available. Check our updated list to make sure you don't inadvertently buy them.

HPRC presents its shortest list to date of still-available Dietary Supplements/Products Containing DMAA! Since our last update in December 2013, 20 more products have been discontinued or reformulated to remove DMAA, and even more have disappeared from Internet retail sources altogether. Currently, we have found only 41 products (out of more than 200 once on the list) that still appear to be in manufacture, in many cases from non-U.S. sources.

Since its April 2013 announcement that DMAA is illegal as a dietary supplement ingredient, FDA has cracked down on manufacturers and suppliers in the U.S. As an example, an FDA News Release last November highlighted the seizure of more than $2 million in products from a single company. For more about DMAA from FDA, read their “DMAA in Dietary Supplements” web page.

Antibacterial soaps – beneficial or not?

HPRC Fitness Arena: Environment, Total Force Fitness
Filed under: Hygiene, Risks
The U.S. Food and Drug Administration (FDA) plans to revise their guidelines for the use and production of antibacterial soaps

The word “antibacterial” is all too familiar to 21st-century consumers. Soaps and cleaning products that tout “antibacterial” or “kills germs” in large print seem to be everywhere. So it may surprise you to learn that recent studies suggest the use of antibacterial soaps may not be as beneficial as once thought. Research now shows that overuse of these soaps contributes to antibiotic resistance, which makes bacteria stronger and less responsive to antibiotic treatment—a potentially major problem in combat zones and hospitals. In addition, recent animal studies have shown that triclosan, the most common active ingredient in antibacterial soaps, may alter the way hormones work in the body. While these soaps are sometimes necessary in hospital settings, scientists caution against using them in our everyday lives.

FDA will now require that over-the-counter antibacterial soaps must prove that their benefit to a consumer’s health is greater than the current risk for harm to the user and the environment. Manufacturers of over-the-counter antibacterial soaps will be given until December 16, 2014, to provide this evidence or FDA will ban their products.

The ban will not affect hand sanitizers and soaps used in hospital settings. To learn more about the proposed ban of antibacterial soaps, read the FDA consumer update.

What’s the story with OxyELITE Pro?

Why has OxyELITE Pro been recalled? Read the OPSS FAQ to find out.

Two versions of OxyELITE Pro have been removed from the market in the past year. Read the Operation Supplement Safety (OPSS) FAQ to find out why, and to get more information from the Food and Drug Administration (FDA). Also, be sure to check back often, as we add answers to other questions about ingredients in performance-enhancing and weight-loss supplements and how to choose supplements safely.

If you have more questions about a particular dietary supplement ingredient or product, please use our “Ask the Expert” button located on the OPSS home page.

Social media “red flags”

You shouldn’t believe everything you read on social media, especially when it comes to dietary supplements and sports products.

Sports products and dietary supplements are often discussed on social media, but think twice before taking other’s word for it. A recent article in the British Medical Journal notes that claims and endorsements made on social media such as Facebook & Twitter are not regulated and may promote statements that have not been supported by science. Some red flags noted include:

  • Paid endorsers. Do you know that some comments and images about a product can come from people (celebrities and non-celebrities) paid by companies to post great reviews about their products? Be careful that such claims may be coming from a paid sponsor and may exaggerate their results from a product.
  • Endorsed hashtags. The hashtag such as “#ad” is a disclosure recommended by the Federal Trade Commission (FTC) to indicate that a social media post is coming from someone being paid (or otherwise reimbursed) by the company of the product they are endorsing. If such a hashtag appears in a social media post, then you know that it is sponsored and may be biased. (For more about FTC’s new endorsement guidelines, visit their FAQs web page.)
  • Biased research. Assessing the science behind claims is the best way to evaluate a product. However, a common practice is that companies cite their own labs and research. When it comes to dietary supplements, it’s best to get information about products from unbiased, evidence-based organizations such as Natural Medicines Comprehensive Database, United States Pharmacopeias (USP), or NSF International.
  • Unbalanced comments. When you scroll through a product’s social media page, do you find that all the reviews are positive? On platforms such as Facebook, companies have the ability to delete comments. A transparent company usually addresses negative comments and provides support to establish its position.

Look for these and other red flags when it comes to dietary supplements and their advertising. If you have a question about a particular sports product or dietary supplement and can’t find the answer on HPRC’s website, please use our “Ask The Expert” button located on the Operation Supplement Safety (OPSS) home page.

Injury prevention Part 6 – Hands and wrists

Even if you haven’t experienced carpal tunnel syndrome, you’ve probably heard of it. For more about this condition and ways to keep your hands and wrists pain-free, read on.

If you’ve been experiencing pain, burning, numbness, or tingling in one or both of your hands, you might be experiencing symptoms of carpal tunnel syndrome. This “tunnel” in the wrist carries the important tendons and nerves that supply your hands with motor and sensory functions, allowing your hands to move and feel. Swelling inside the carpal tunnel can squeeze the median nerve that passes through it, causing discomfort. According to the Defense Medical Epidemiology Database, in the military, women are more likely than men to develop this condition. It’s also more likely to develop with age and rank. There are surgical and non-surgical treatments for carpal tunnel syndrome, but as the saying goes, “An ounce of prevention is worth a pound of cure.” The University of Maryland Medical Center has advice, which includes:

  1. Do exercises to keep your muscles and tendon flexible. (See the UMMC link above for detailed instructions.)
  2. When performing repetitive activities your the wrists and hands, take frequent breaks, even if it’s just for a minute or two at a time—called “microbreaks.”
  3. Use correct posture and technique, especially wrist position when using a keyboard or hand tools.
  4. Make sure that your work area is ergonomically sound. Military-specific information is available from both the Army Public Health Command and the Naval Safety Center.

HPRC’s Physical Fitness domain also has a section on Injury Prevention.

Injury Prevention Part 2 – Don’t neglect your ankles!

Injuries to the ligaments of the ankle are very common in the military, but there are some important tips you can use to help prevent them.

Stretching and strengthening the muscles of the foot and ankle can help you prevent (and recover) from ankle sprains. The Foot and Ankle Conditioning Program from the American Academy of Orthopaedic Surgeons focuses on recovering from injury, but it includes well-illustrated exercises that are good for preventive conditioning too. Here are some other exercises useful for strengthening the foot and ankle structure:

  • From a seated position, “pretend” writing the alphabet with each foot, in both upper- and lower-case letters.
  • Stand on one leg on a pillow for 10 seconds and then switch legs. Be sure to have something nearby to grab for balance if necessary.
  • From a seated position, use a resistance band looped to a secure surface, and wrap the other end around your forefoot; then move your foot/ankle forward, backward, and side-to-side, flexing at the ankle.

An ankle sprain involves damage to ligaments—bands of tissue that help hold joints together—in the foot and ankle, usually from the force of landing wrong on your foot. In military populations, ankle sprains are very common, significantly affecting operational readiness. In fact, ankle sprains are more common in the military than in civilian populations and more likely among women than men. By strengthening the muscles in your legs and feet, you can give more support to your ankle in the event of a misstep or an encounter with uneven terrain. The transition from military boots, which offer more ankle support, to traditional athletic shoes may also leave you and your ankles feeling vulnerable to twists and sprains. Start including ankle-strengthening exercises into your daily workout routine to help keep your ankles strong and free from injury.

DoD’s DMAA report

The DoD Safety Review Panel has completed its review of DMAA, and the report is now available on HPRC’s website. The result is that DMAA-containing products will no longer be sold on military installations.

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.

FDA warning: Illegal diabetes products

FDA has cracked down on misleading claims and warns consumers about potentially harmful products marketed to prevent or treat diabetes.


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.

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