Filed under: Exercise
Coconut water, a potassium-rich liquid found in young green coconuts, has become a popular hydrating alternate for some active individuals. Some active individuals choose coconut drinks over other sports beverages because it is natural and contains electrolytes and minerals such as sodium, chloride, glucose, and potassium. Although natural coconut water is a fine option for active individuals to stay hydrated, the sodium content of coconut water is low, so some scientists argue that individuals who participate in vigorous exercise should consider sports drinks, which have been formulated to replenish sodium lost during extended and/or vigorous physical activity. If you exercise vigorously for more than an hour, the ACSM recommends fluids or salty snacks that contain a bit more sodium (20-50 mEq/L or ~460-1,150 mg/L) to help you replenish sodium lost during strenuous exercise.
Operation Supplement Safety (OPSS) is about to launch this summer and will answer many of your questions about Dietary Supplements. Watch for HPRC’s announcement coming soon.
There are any number of excuses for not exercising or counting calories, but not having the ability to track your progress and have it with you at all times is a dwindling one. Smartphone physical activity applications (SPAA) are growing in popularity and making it easy for users to receive information regarding their fitness and nutrition. Finding the right one for you—among thousands—may take some legwork, but the American College of Sports Medicine (ACSM) review of the different types of fitness apps can help you choose.
A recent study identified features that consumers find most valuable— apps that include goal setting and problem solving (for example, alternative exercises for when it’s raining) seem to be the most successful. Two other features that users ranked high were automatic tracking of physical activities and receiving feedback on fitness accomplishments.
A helpful application created by the Navy Operational Fitness and Fueling Series (NOFFS) is available here. Also check out HPRC’s tip on a good nutrition tracking application. Find an application that meets your needs and bring fitness with you everywhere!
The cool-down—a practice so engrained in our exercise habits that we assume it’s important. But, the truth is, the topic is understudied, and evidence for or against cooling down is still up for debate. What is a cool-down and what is it supposed to do? The American College of Sports Medicine (ACSM) recommends a period of low- to moderate-intensity aerobic or muscular endurance activities after exercise to gradually reduce heart rate and blood pressure and remove metabolic byproducts from the system. For some, this may be a slow jog down the street, or an easy ride around the block after a workout with the hope of also preventing delayed onset muscle soreness (DOMS). The long-standing theory behind cooling down was that it helped to remove lactic acid from the system, a substance that could later cause muscle aches and soreness. However, it is believed that DOMS is the result of minor muscle damage due to novel or intense exercise, but we do know that lactic acid is not the culprit. During cool-down—active recovery—more lactic acid is removed from the system than during passive recovery, i.e., no cool-down. But is this a good thing? In a study of cyclists, researchers found that when subjects stopped exercise abruptly, lactic acid turned into glycogen, a fuel for the muscles. But when the cyclists gradually tapered off activity, less glycogen was made, leaving less energy for the muscles. These results indicate that cooling down might not be beneficial and may waste useful energy for the muscles.
On the other hand, a cool-down lowers elevated heart rates faster than passive recovery does and may prevent post-exercise dizziness. Stopping abruptly after exercise can cause blood to pool in the dilated vessels of the legs and feet, which may lead to a feeling of light-headedness and/or dizziness. Keep in mind, however, that these symptoms can also be related to other post-exercise conditions such as low blood sugar, low blood pressure, dehydration, or even hyponatremia. If you experience these symptoms, check with your doctor to find out if there are other causes.
Scientists agree that cooling down is also beneficial for people with cardiovascular conditions and heart disease where the coronary vessels are narrowed due to atherosclerosis (fatty deposits), as blood return to the heart may be compromised without it.
ACSM currently recommends at least 5-10 minutes of cool-down, with at least 10 minutes of stretching after exercise. However, more research is needed to determine the value and ideal recommendations for cooling down. If stopping exercise abruptly causes symptoms of light-headedness and dizziness, then a cool-down is a good idea.
The Navy Operational Fitness and Fueling Series (NOFFS) is an important training program for sailors and Navy health professionals, combining sports science and injury prevention information to promote optimal human performance. The exercises in the series have been designed to train sailors for the types of activities they can expect to perform during operational duties. The NOFFS program is currently available as an app for iPhone, with on-the-go reference and training assistance right at your fingertips. The app features pictures, videos, and step-by-step exercise instruction, as well as nutrition tips and information. Download the app for free from the iTunes App Store!
It’s been commonly thought that exercise can ward off the effects of sleep loss, but it turns out that exercise only mitigates sleepiness and fatigue for an hour and doesn’t seem to have any effect on boosting performance throughout the day. Although regular exercise—both strength training and high-intensity endurance—does help you sleep better, it can’t replace lack of sleep—only actual sleep will do that. The loss of sleep affects physical performance primarily by reducing your motivation to exercise—so, when thinking about your workout plan for the week, include a plan to get enough sleep.
For information on how to improve the quality and length of your sleep, check out HPRC’s Mind Tactics Sleep Optimization section. For information on how sleep loss impacts other areas of fitness, check out the HPRC’s Total Force Fitness article The impact of sleep loss on total fitness, and for information on physical fitness check out HPRC’s Physical Fitness domain.
Working out by yourself is fine if you’re self-motivated, but getting a buddy to tag along can provide the motivation needed to really ramp up your workout. Let’s face it—a bit of friendly competition can help you push harder than if you were alone. In fact, research has consistently shown that performance is substantially improved when you exercise with someone (even a virtual partner)—unless the workout is complex or involves tasks that require coordination, when the performance can degrade (i.e., "choking under pressure"). So, for best results, practice your difficult routines with a trainer, and then engage in healthy competition to optimize your performance. Keep in mind that not just any friend will do. It’s best to get a buddy whose skill level is similar to your own.
If you have ever bought a pair of toning shoes, you probably noticed you haven’t developed a Kardashian-curved derrière or a Brook Burke body just from walking around in them. You’re not alone. Recent developments have brought toning shoes back into the spotlight for the media and scientific communities. An independent study by the American Council on Exercise found that these kinds of toning shoes do not increase muscle activation or caloric expenditure compared to regular athletic shoes. However, a positive outcome may be that these shoes have motivated people to get out and walk, a physical activity that has many health benefits—without special shoes! Caveat emptor!
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.
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.
In a recent study investigating risk factors for discharge from Army Basic Combat Training (BCT), researchers concluded that increased risk for both men and women was associated with failure on the initial two-mile run test. The current Physical Fitness Tests (PFT) or Physical Readiness Test (PRT) use a one and a half to two-mile run test to assess cardiovascular, or aerobic, fitness.
When mapping out a fitness program, learn the components of the FITT principle and apply them for each type of training. FITT stands for “frequency,” or how often; “intensity,” or how hard; “type,” or the kind of activity; and “time,” or how long. Progression (see below) is also an important part of an exercise plan. Using the FITT Principle, here are some guidelines to help optimize your cardiovascular fitness.
Frequency. The U.S. Surgeon General and other U.S. government agencies recommend physical activity on three or more days a week.
Intensity. According to updated guidelines The American College of Sports Medicine (ACSM) recommends adults engage in moderate-intensity exercise (i.e., at 40-60% Heart Rate Reserve (HRR)) five days a week or vigorous-intensity exercise training (i.e., at ≥ 60% HRR) three or more days a week. They also recommend a combination of moderate- and vigorous-intensity exercise. You can use this calculator from Kirtland AFB to determine your HRR.
Type. ACSM defines aerobic activities as being continuous, rhythmic, and using large muscle groups, such as your lower and upper body muscles. Examples of these kinds of activities are running, biking, swimming, rowing, and jump roping.
Time. The Surgeon General, ACSM, and American Heart Association recommend expending at least 1,000 calories per week through exercise (i.e., in addition to calories burned through normal everyday activities). This can be achieved through moderate-intensity exercise, as described above, and should last about ≥ 30 minutes per day for a total of ≥ 150 minutes per week; or with vigorous-intensity exercise for ≥20 minutes per day for a total of ≥75 minutes per week. The maximum safe duration is unknown, but exercise lasting more than an hour and a half increases risk of overtraining and/or overuse injuries such as stress fractures.
Progression. During the initial phase of an exercise program, ACSM recommends increasing duration (minutes per session) gradually. Increasing 5-10 minutes every one or two weeks over the first four to six weeks of an exercise program is reasonable for healthy adults. After an exercise routine has been maintained for one month or longer, it is reasonable to gradually increase frequency, intensity, and/or time over the next four to eight months. As a general rule of thumb, though not scientifically backed, increasing your workloads or volume by 10% will also help you gradually progress your exercise program.
Due to the repetitive and rhythmic nature of aerobic exercise, overuse injuries can occur as a result of your training. Cross training—training with a variety of aerobic exercises—is recommended. Examples of this would be alternating running, swimming, and rowing exercise sessions.
Part two of this series (upcoming) will address the muscular strength component of PFT/PRT.