You are here: Home / HPRC Blog
RSS Feed for Environment

HPRC Blog

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: Environment

Too sick to exercise?

Feeling under the weather? Find out when bed rest is best—or when it’s safe to sweat it out.

Is it safe to exercise when you’re sick? Those who have strict workout schedules aren’t likely to let the sniffles get in the way of their physical fitness. Exercise benefits include better weight control, improved mood, more energy, and healthier sleep. What’s more, just 30 minutes of regular exercise 5 times each week can improve your heart health and boost your immune system too.

 

Moderately exercising while you’re sick can be safe and, in certain cases, might actually improve symptoms such as congestion and low-energy. First, you need to determine “how sick is sick.” You can figure this out by using the “neck rule.” If you have symptoms above the neck—including sore throat, nasal congestion, sneezing, or watery eyes—then moderate workouts can continue. If your symptoms are below the neck—including cough, fever, fatigue, or body aches—then rest until the symptoms are gone. You can also use your temperature to determine whether exercising is okay. If you have a temperature of 101°F or higher, moderate or vigorous exercise isn’t safe due to risks of heat-related illnesses and dehydration.

 

Ultimately, the decision to exercise when you’re sick is up to you. If you’re too weak and fatigued to get out of bed, exercising might not be the best choice. If you have symptoms of a cold and your temperature is below 101°F, light to moderate exercise could be good for you. Make sure to see a doctor if your symptoms don’t improve or get worse. 

Unmasking high-altitude training

HPRC Fitness Arena: Environment, Total Force Fitness
Should you be using your Pro Mask for altitude training?

Using your military Pro Mask or other commercial mask device as a method of respiratory muscle training (RMT) isn’t going to prepare you for higher elevations. Increasing the strength of your respiratory muscles which help you breathe—your diaphragm and the muscles between your ribs—will improve aerobic fitness, especially for long-duration tasks.

RMT can be achieved through whole-body aerobic exercise, upper-body strength conditioning, and some commercial RMT devices. Studies show that RMT slightly improves performance in those who are already aerobically fit (e.g., military personnel). It offers somewhat more benefit for those less fit or with chronic conditions.

Your Pro Mask was made to protect your lungs, eyes, and face from chemical and biological agents, radioactive particles, and battlefield contaminants. It doesn’t create enough airflow resistance to help improve aerobic capacity. In addition, it wasn’t designed as exercise equipment. There is no scientific evidence that suggests using commercial masks at normal altitudes will improve your performance at high altitudes. Read more about the U.S. Army Research Institute of Environmental Medicine’s (USARIEM) review of Pro Masks and commercial products for exercise training. Check out HPRC’s take on using high-altitude masks and improving work performance at higher elevations.

Blue light’s bright and dark sides

HPRC Fitness Arena: Environment, Total Force Fitness
Filed under: Rest, Sleep, Technology
What is “blue light,” and how does it affect you?

Blue light is a type of light emitted from all electronic devices and energy-efficient light bulbs. It can give you an energy boost equal to or better than 2 cups of coffee. Blue light may even enhance athletic performance. Sounds great, right? But what if the missing piece of your performance puzzle is sleep? An energy boost during the day may be welcome, but using electronic gadgets at night can be detrimental to your sleep health. The blue light they emit can suppress the secretion of melatonin, a powerful sleep hormone, and disrupt your natural circadian rhythm. Try to manage your exposure to blue light with these tips:

  • During the day, take advantage of the bonus your electronic devices give you to boost your attention, reaction times, and mood.
  • Shut off all electronic devices at least 2 hours before you need to go to sleep.
  • Consider wearing blue-blocking glasses when you need to sleep but can’t avoid blue light.
  • If you like having a nightlight, use dim, red bulbs. Red light has less impact on your melatonin levels. (Parents take note for the nightlight in your child’s bedroom.)

One last tip: During the day, get plenty of bright daylight. It makes you feel better during the day, and it will help you sleep better at night.

Running: indoors or outdoors?

Learn about the pros and cons of running indoors versus running outdoors, especially now that colder weather is coming on.

Training on the treadmill and “overground” running are not the same. If you’ve experienced treadmill running and find yourself more tired afterwards than you would on an outdoor run, you’re not alone. It seems athletes actually run slower on a treadmill than their normal pace outside, yet they perceive treadmill running as being more exhausting. In other words, even though it feels more difficult, treadmill running is usually less intense and less physically challenging than running outdoors.

If you’re training for an outdoor race, ideally you should run most of your training miles outside. However, running indoors can be helpful if you’re recovering from an injury since running on a treadmill is easier on your joints than running outside on concrete or even grass. When you want or need to run indoors on a treadmill, set the incline at 1–2% to increase your exertion level to more closely replicate your outdoor runs.

If you decide to run outside during a cold spell, take a look at our article with tips for staying safe in cold weather and the many resources on cold environments where you can find more ways to keep warm and hydrated even in frigid weather. Remember: Whether you stay in or venture out, any exercise is better than none!

A “natural” way to recover

If you’re in any stage of a recovery process (physical, mental, or spiritual) it may be helpful to get outside and spend some time in nature.

Exposure to a natural green environment can help reduce your stress levels and improve your health and well-being. So, feeling blue? Go green! Some of nature’s restorative benefits include improved positive mood, energy, and vitality; decreased anxiety, depressive thoughts, perceived stress, and hostility; as well as improved recovery times after surgery and less need for pain meds.

Exposure to nature can also reduce your heart rate, blood pressure, blood sugar, and stress hormones, as well as improve your sleep, immune function, and brain activity. Interestingly, people who live in neighborhoods where streets have more trees report feeling healthier, with fewer symptoms of poor health such as heart attack, stroke, obesity, and diabetes. Neighborhood greenness has also been tied to longer life expectancy.

Depending on where you live, finding a natural environment can be tricky. You can find state and national parks online or look for local parks and gardens in your area. Even walking along a neighborhood street with lots of trees, spending more time viewing nature (through a window), or having indoor plants within view can make you feel better. You may want to experience nature on your own, with a buddy, or with a group of fellow service members or veterans. For group outdoor recreational activities, check out the Sierra Club Outdoors program (or, specifically, their Military Outdoors program). So if you’re feeling stressed, down, or not your usual self, get outside and go green!

Noise pollution and hearing loss

HPRC Fitness Arena: Environment, Total Force Fitness
Helicopter propellers, jet engines, explosions, moving vehicles, gunfire, and more—all sources of noise pollution that troops may experience in the line of duty—can affect your hearing.

Noise-related hearing loss is a tactical risk for individual warriors and unit effectiveness. Being able to hear well is crucial for effective communication and—perhaps more important—for survival. While the military has done extensive research and established standards regarding noise and noise exposure, there are a few things you can do to help minimize your risk of this occupational hazard.

  • Wear hearing protectors when firing weapons or traveling in noisy vehicles or aircraft.
  • Make sure that earplugs such combat arms earplugs (CAE) fit properly to protect your hearing but still communicate effectively.
  • Replace lost or damaged hearing protectors as soon as possible.
  • Limit exposure to “annoying noise” during normal daily activities. Trying to ignore noise can increase your heart rate and blood pressure and cause sleep problems and other negative health effects.
  • Report any signs of hearing loss as soon as possible.

Hearing loss, including tinnitus, has become an "invisible" injury and an accepted outcome of military service. Blast injuries from improvised explosive devices (IEDs), RPGs, and mortar rounds are the largest cause of hearing loss for forces in Iraq. Compensation payments for hearing loss as the primary disability increased 319% between 2001 and 2006. While there is currently no cure for tinnitus, there are treatments available.

The DoD Hearing Center of Excellence is committed to preventing, treating, and rehabilitating hearing loss and auditory injury for service members and veterans. HCE offers evidence-based clinical care in collaboration with other organizations and Centers of Excellence to improve quality of life for hearing-impaired service members and raise awareness about noise pollution and occupational safety.

Noise pollution may be an inevitable part of serving in the military, but it doesn’t have to leave you with a permanent reminder. Do what you can to help hold on to your hearing.

Don’t get “computer eyes”

Take regular breaks and adjust your computer environment to prevent eye strain and enhance performance.

Sitting in front of a computer for hours can make your eyes tired, and your visual performance can suffer. To help with potential negative effects, create an environment that has equal brightness everywhere around your computer screen. Try these tips to help:

  • Reduce intense fluorescent lights.
  • Turn on some lights if you usually look at computer screens in the dark.
  • Dim excess light coming through windows with blinds, tinting, or window covers.
  • Avoid glare on your computer screen.
  • Take microbreaks to look at distant objects.

If you’re in an office environment, if possible, turn off overhead lights and have a table lamp for softer light. If you can’t control the lighting in your environment, there are screens you can place on top of your computer screen to reduce glare. In a previous article, we highlighted how 30-second microbreaks every 20 minutes can ease physical discomfort and improve mental performance when working in front of a computer. Similar breaks also help reduce eye strain. Experts suggest looking at a distant object at least twice every hour to help prevent visual fatigue. So if you take a break every 20 minutes for brief stretching, make sure it also includes looking at a distant object to help both your eyes and body. 

Tips for G-TIP

HPRC Fitness Arena: Environment, Total Force Fitness
Flying under G-forces? Here are tips you can use to improve your G-tolerance during flight.

Training for flight in dynamic and high-acceleration aircraft requires both good cardiovascular health and anaerobic capabilities; part of well-rounded fitness! Have you heard the myth that all fighter pilots are short, stocky, and need high blood pressure? Not true, you too can develop good G-tolerance! Regular cardiovascular conditioning paired with strength-training programs will properly prepare you for flight under Gs. A strong lower body helps push blood upwards where you need it, in your heart and brain. Being aerobically fit gives you the endurance to keep pushing and not fatigue as quickly while doing the Anti-G Straining Maneuver (AGSM). AGSM is a two-component maneuver pilots perform under g-loads that involves breathing and muscle contractions to increase your blood pressure and maintain blood flow to your brain. Read more here

Aviation and hypoxia

HPRC Fitness Arena: Environment, Total Force Fitness
Filed under: Aviation, Flight, Hypoxia
Hypoxia in aviation is a real threat. Learn the signs and symptoms to recognize it.

Hypoxia, or insufficient oxygen supply to the body, is a stress factor associated with high altitude in aviation. It’s caused by low oxygen levels and decreases in partial pressure. Flight above 10,000 feet is dangerous and restricted without supplemental oxygen, and even the best oxygen and pressurization systems fail sometimes. Above 10,000 feet, an aviator’s “Time of Useful Consciousness” (TUC) begins; this means that you’re going to start having problems focusing, reacting, and making decisions. At 15,000 feet your TUC is around 30 minutes, at which point you’re more likely to be unconscious than not. At 22,000 feet it’s only 5–10 minutes, and by 28,000 feet it can be as fast as 3 minutes! Look out for these signs (what you can see in somebody else) and symptoms (what you can notice in your own body):

  • Cyanosis (bluing of the fingertips or lips)
  • Headache
  • Decreased reaction time
  • Impaired judgment
  • Unexplained happiness/euphoria
  • Visual impairment
  • Drowsiness
  • Lightheaded or dizzy sensation
  • Tingling in fingers and toes
  • Numbness

If you notice any of these signs or symptoms, remember to find the emergency oxygen, use it, and land safely!

Decompression sickness

HPRC Fitness Arena: Environment
Filed under: Diving, Scuba
Decompression sickness can happen at altitude with loss of pressure. Know the symptoms.

Decompression sickness (DCS), also known as “the bends,” is well known to occur in divers. However, it also can occur in aviation, especially when there is a sudden or unexpected loss of cabin pressure above 18,000 feet. DCS occurs when the dissolved gases inside the body come out of solution to form bubbles. As these bubbles move throughout the body, problems occur. There are different types of DCS, but here are some common symptoms to be aware of:

  • Localized or deep pain in the large joints
  • Itching or the sensation of insects crawling on your skin
  • Tingling
  • Numbness
  • Confusion
  • Memory loss
  • Dizziness
  • Visual abnormalities
  • Headache
  • Fatigue
  • Loss of balance or vertigo
  • Dry, persistent cough

If you suspect DCS, first land safely as soon as you can. Treatment may involve breathing oxygen or time in a hyperbaric chamber. If you ever experience these symptoms after a loss of pressurization above 18,000 feet, contact your doctor or emergency room as soon as possible and report your recent exposure.

RSS Feed for Environment