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HPRC Fitness Arena: Physical Fitness
The saying goes that “less is more,” but when it comes to exercise intensity, that might not be the case. We know that some exercise is better than no exercise, but is more-intense exercise better than moderate exercise? How hard should you push? And what are the benefits? With the growing popularity of high-intensity workouts, it’s important to consider both the risks and the benefits.
The role of intensity during exercise has been studied before. For example, the risk of death in older adults is lower for those who walk at a faster pace than for those who walk at a more leisurely pace. However, new research demonstrates that pushing yourself during a workout not only helps make you mentally tough but may also release chemicals into your body that help you develop bigger, stronger muscles.
During “stressful” or high-intensity exercise, your body kicks into “fight or flight” mode and releases hormones such as adrenaline and dopamine to push your system into high gear: increased heart rate, increased breathing rate, and increased oxygen to muscles. A recent study found that these hormones, when released during stressful exercise, sent messages to muscle cells to develop larger and more efficient muscles—at least in mice. The body only releases these chemicals when it feels stressed (for example, during intense exercise). If the body doesn’t feel stressed (as during light exercise), it doesn’t release these chemicals, so it can’t send signals to the muscles.
The good news is that exercise intensity is relative, so anyone should be able to exercise at a level that releases these hormones. Whether you’re just starting out or you’re a seasoned athlete, you can exercise to a level that is intense for you. Shooting for your target heart rate is a good start to gauging intensity. Not every workout needs to top out the intensity scale. In fact, doing too much too often can lead to overtraining and potential injury. Remember to listen to your body and incorporate rest or light days into your workout regimen.
Activity monitors have become increasingly popular tools to help people get and stay on track with their fitness (and dietary) goals. But, researchers from Iowa State University wanted to see just how accurate some of the popular monitors really are when it comes to reporting how many calories you burn during exercise. It turns out that the majority of the devices they tested gave pretty accurate estimates (within 10-15% error). The BodyMedia FIT was the most accurate one tested, with only a 9.3% error rating, which is close to some more expensive devices used for research purposes. Other monitors such as the FitBit Zip, FitBit One, Jawbone Up, and Nike Fuel Band all fell below 15%. Since many people tend to overestimate their activity levels on their own, an accurate activity monitor is an important tool to help people keep better track of their exercise habits. Check out our comparison chart to find out more about these monitors.
You’ve probably seen the pictures on social media and in the news: a very pregnant woman, with a heavy barbell on her shoulders, mid squat, in an Olympic powerlifting move. But is it safe for mother and baby? If this is a situation you might find yourself in, and/or you’ve talked to your doctor about a pregnancy exercise regimen, there are some things you should know about weight lifting and exercise. Read HPRC’s “Lifting weights during pregnancy” for more information.
Running provides an inexpensive and effective way to get your child or adolescent excited about physical fitness for a lifetime. Beyond the physical health benefits, running can also lead to improvements in classroom behavior, self-control, self-esteem, alertness, enthusiasm, creativity, and maturity.
For children of all ages, running is one of the most versatile and natural physical activities. In younger children, running should be encouraged through fun activities such as tag, capture the flag, the fox and the hound, and red light green light. By keeping running fun, your child may learn to enjoy exercise at an early age, helping him or her maintain those habits as he/she gets older.
For older children interested in the sport of running, there are some additional ways to help your child become a strong, healthy runner. Learn more about proper running form, training, hydration, diet, shoes, and safety, which may help your child’s performance and may also decrease his or her risk of injury.
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.
Suicide is a complex issue with many contributing factors, including mental health issues. Focusing on treating mental health issues and strengthening mental fitness is key for suicide prevention. Currently, efforts within the military focus on education, early intervention, decreasing stigma towards mental health treatments, and adapting a holistic approach to fostering mental fitness—which includes exercise. Learn more about how physical activity and regular exercise can improve mental health in HPRC’s answer to “Can exercise be a part of suicide prevention?”
Antigravity treadmills are becoming increasingly popular in injury prevention and rehabilitation settings. These special treadmills reduce the stress placed on the lower body during rehabilitative exercises, like running and walking, while still conditioning muscles. However, there are still questions as to whether the scientific evidence supports their considerable cost. For more about the use, evidence, and cost of these devices, read HPRC’s “Effectiveness of Antigravity Treadmills for Injury Rehabilitation.”
Whether training for a mission, an athletic event, or simply to maintain your edge, there are strategies you use to enhance your chance of success, including “rules” such as figuring out where you are before you start and setting up an environment that supports your new plan. Check out HPRC’s new card, “Peak Performance: Rules of Engagement,” to learn all of them. And for even more information, check out the accompanying Performance Strategies.
The Military Health System has declared that June is Men’s Health Awareness Month. Understanding your personal health risk factors and getting screened for potential issues is the best way to stay healthy at any age. Prostate, lung, and colorectal cancers are the three most common cancers among men. The good news is that exercise and physical activity have been liked to lower risk and lower rates of death for these types of cancers. So stay active and visit a doctor for regular health screenings, and pass on to the boys in your life about the importance of regular exercise and physical activity. Living a healthy lifestyle and getting screened for health issues are important ways to maintain readiness, resilience, and optimal performance.
More than two million new cases of skin cancer are diagnosed each year, and the number is growing. Skin cancer is a major public health issue, and with proper precautions you can decrease your risk considerably. Hopefully this information on sun safety will help you, whether you are a Warfighter or dependent, stay safe during all outdoor activities!
Ultraviolet radiation (UVR) has been identified as the most important risk factor for both melanoma and non-melanoma skin cancer. Exposure to UVR weakens the skin’s elasticity and can result in sagging cheeks, deeper facial wrinkles, skin discoloration, burn, skin aging, photosensitivity, and cancer. Taking steps to safeguard yourself is crucial, especially when participating in outdoor activities or exercising.
Sweating increases the skin’s sensitivity to the sun’s rays, magnifying the risk of sunburn and skin damage. Athletes who practice outdoor sports have been found to be at increased risk for skin cancer. Remember—the weather does not have to be sunny and hot for you to get sun damage. Ultraviolet rays penetrate clouds, exposing you to 80% of the UVR. Even skiers and mountain climbers are at risk for sun exposure and skin cancer because of the stronger UVR at altitude.
Follow these precautions from the Occupational Safety and Health Administration (OSHA) whether training for the PRT, patrolling, road marching, or participating in a summer league softball game:
Avoid burning. Avoid sun tanning. Also, try to avoid sun exposure during midday (11 a.m. to 3 p.m.) when the rays are the strongest.
Seek shade. When possible, especially during midday, seek shade under a tree or tent.
Cover up. Wear protective clothing, including hats, long-sleeved shirts, and pants when going outdoors. Keep in mind protection decreases when clothes are wet.
Use extra caution near water, snow, and sand. Ultraviolet rays can reflect off of these surfaces, which can increase your chance of sun exposure and skin damage.
Apply sunscreen. Use water-resistant sunscreen and apply 15-30 minutes prior to sun exposure to allow for it to absorb. Also, reapply after swimming, sweating, or toweling off.
Wear sunglasses. Protect your eyes when working, driving, participating in sports, taking a walk, or running an errand. Solar ultraviolet B radiation can cause an increased risk of cataracts and cancer of the skin around the eye without proper cover.
It’s always important to remember hydration when engaging in outdoor activities as well! HPRC has useful tips on hydration and the consumption of sports drinks and caffeine during exercise in the heat.