Indiana Jones Rocket Sled

The new Indiana Jones movie came out this past weekend, the Kingdom of the Crystal Skull. It is set in 1957 with fun fitness and iconry of the era, for future blog posts. Today - the Rocket Sled.

In the early part of the movie, Indiana Jones and the Soviet Russians brawl through a US military testing base in Nevada. Jones and a Russian officer wind up on a rocket sled, which blasts them on a speed track into the desert.

Rocket sleds are one of several devices that create and test the effects of high acceleration on equipment and the people who use them. High acceleration forces occur when jets take off quickly, when launching a space flight, to eject from a hit (compromised) fighter jet, on roller coasters and spin and fall rides, when you fall from a height, and any time you change speed and/or direction quickly. Interesting changes occur in the body under acceleration. Acceleration is one of the areas of my study as a research physiologist and was my work for a time at two facilities testing air vehicle and human systems.

G-force is a measure of acceleration, not force, but the term g-force is also used for the reaction force that results from acceleration. More on meaning, spelling, and math of g and G in another post. Too much g-force can result in g-LOC (Loss of Consciousness), pronounced "jee-lock"in English, but just as meaningful when using the Cyrillic pronunciation of "loss." When piloting a multi-billion dollar property (the fighter jet) G-LOC is not a good thing for anyone. The pilot may convulse, called "doing an Elvis" because the flailing looks like playing an air guitar - a real air guitar. Then the pilot may "ding" (lose consciousness) and the vehicle may "descend below the level of the terrain" (crash) and "disperse energetically" (explode) and "value unfavorably" (be destroyed), and the crew and anyone they land on may "achieve a negative health status" (die).

So we test.

A rocket sled is a small platform. Rockets propel it on the ground on rails. It creates high onset g-forces for a time limited to the length of the track. When personnel or equipment riding it sit as in a car or plane, they experience acceleration pressing them from front to back (on an x-axis).

To measure the higher g-forces with short onset experienced in jet bail-out procedures, a vertical ejection tower can be used. A small seat is propelled quickly upward by a contained blast force under it (like lighting a bomb). If they are positioned to sit upright, the acceleration acts on them from head to foot, on their y-axis.

To experiment with varying accelerations over different amounts of time and onsets, one device used is a centrifuge. A long support arm swings around and around a center anchoring point -like swinging a ball on a string around your head. A container, often ball shaped, at the end of the support arm holds the equipment or personnel being tested. The ball can rotate to position the people inside at any angle to simulate the changing positioning of a cockpit during maneuvers, for example.

What happens to the people in these testing devices? Often they throw up all over my nice equipment. Some of my test subject pilots used to have contests who could eat the worst thing to redisplay on testing day. One ate plastic bugs just for the fun he was sure to cause - then he didn't throw up, no matter what we did to him. In vertical (y-axis) ejections, there is high impact and acceleration forces on the discs and spine. Back injury is a concern for ejection scenarios. Vibration, both during acceleration and non-acceleration situations, such as for helicopter and jack hammer operators seems to be a high contributor to back pain. It is not known if the various vibration devices sold as fitness devices are of the kind (vibration frequency or amplitude) that contribute to joint pain. G-LOC is another consideration. Why do we test it? To see how to prevent it, if we can screen for who is more likely to get it, if we can train those prone to it to be more resistant, and so on, in g-force tolerance improvement programs (g-TIP).

The set of photos at right is a well-known one of USAF Colonel John Paul Stapp, M.D., Ph.D., riding the rocket sled. He was a pioneer of acceleration study and is also known as the originator of the expression "Murphy's Law" for things that can go wrong. The effect on his face along the x-axis is not from his high speed, but the acceleration which is increasing in photos ii and iii, and decreasing in v and vi. Even though his speed is greatest in photo iv, speed is not increasing or decreasing much, so there is little effect.

More on the interesting effects of acceleration and environmental testing from roller coasters to jets to movies in posts to come.

Labels: aerospace, circulation, disc, g-force, injury, lower back, performance enhancing modality

Permalink | 1 Comments| Email Post

Post your comment

A Reader Asks About Osteoporosis and Walking Lightly

One good question launched many answers. The post Walk Lightly - Shock Absorption for Happier Joints explained a light step prevents joint, soft tissue, and plantar fasciitis pain. In the comments, Carol asked if there were, "a connection between walking lightly and oesteopenia?" This is interesting, since osteopenia is lower than normal bone density, lack of enough pulling or tension on the bones reduces bone density, and a certain amount of vibration may help bones. The simple answer seems to be, that walking lightly should not be enough to reduce bone density, by itself.

Walking, running, and jumping lightly is good exercise to load the bones, while being better for your ankles, knees, hips, and spine than jarring with each step. The post Why So Many Aerobics Injuries? cited news accounts attributing joint pain and injury to high impact activities, with examples of popular aerobics personalities of the 1980s who now say they are too crippled to exercise. Their injuries were avoidable, but not by avoiding impact exercises. Impact activities can be done safely by not stomping down hard. Even repeated jumps from a height can be done with soft landings. Good athletes run, jump, and box with far less impact than most people walk, and have good strong bones. Exercise, done right, is crucial for your bones - Exercise is More Important Than Calcium Supplements for Bones.

When muscles pull your bones during walking, running, and other exercise, the pulling increases bone density. Adding external weight loads bones further. That is a major way weight-bearing and weight lifting exercise increases bone density. The effect of muscles contracting to provide good shock absorption when moving also pulls on the bones,which should be good. The post Forensic Anthropology and Bone Density looked at influencing the shape of our bones by how we move.

The reader went on to comment, "I have always been very light on my feet, and now in my 50s I have found out I have low bone density. I have a cousin who shakes the house when she walks who has been told that she doesn't ever have to worry about her bone mass." Walking lightly alone should not have caused the osteopenia. Questions would be, what other exercise the reader does, and what things might be decreasing her bone density? For the cousin, "shaking the house" by itself may not be enough bone stimulus that anyone could tell her that she "doesn't ever have to worry." Has the cousin taken a bone density test and was found to be high (for whatever reason)? Then you can say there is lowered risk of fracture. Is this cousin is very heavy, which helps load bone? Does this cousin do regular exercise to increase her bone density? It is not likely to be a valid prediction that someone never has to worry about bone density just because they walk badly.

The reader went on to ask, "I went to a bones for life class and was taught to do heel bouncing to stimulate bone growth. i.e. dropping repeatedly from toes onto heels while standing in proper alignment. Do you agree with that exercise?" I did a few searches on the bones for life class and found that the class uses many exercises, not bouncing on the heels alone. Bouncing for a few minutes would not be enough to undo sedentary life style, and the various things people do that actively take away from bone density. You need to do all the other exercises. How much the shock wave of the impact may additionally load or stimulate the bone is still an open question.

There are studies looking at effects of vibration and tapping on bone building. Mechanisms have been studied from the effect on cat bones of their purring, to various machines that bang or vibrate. Some advertising for vibration machines goes as far as making claims that they will increase bone density. So far, none have been found to have as much bone building effect as muscular activity (exercise). Too much occupational vibration, like jack-hammer, helicopter and similar environments produces joint pain, injuries to the spine, eyes, ear, nervous, and other systems. That was one of the topics I was looking into when I did aviation medicine research. A news article that came out on last year's fitness fad of vibration plates promising weight loss and fitness building, mentioned a few of the problems with too much vibration, and, ironically had an accompanying photograph showing severely hyperlordotic (overarched) lower spine positioning by a person listed as the trainer. Hyperlordotic spine posture, by itself, damages the facet joints of the spine over time. It seems safe to say that the jolting of the vertebral joints against each other in this overly arched position would only be worsened by vibration. The post Prevent Back Surgery shows examples of overarched lower spine and why it causes so many injuries in fitness.

It would be interesting to know if low levels of vibration, through tap dancing, Flamenco dancing, pogo stick jumping, and similar activities, would change bone compared to the same amount of exercise without the impact. Some studies claim that swimmers or cyclists do not have as high bone density as runners, while others do not find that when they control for the direct muscle work applied to the area. There are even studies showing that Tai Chi, a most mild form movement with almost no foot-falls at all, can increase bone density in older people, just from the movement.

Along with walking or running, and weight lifting to build bone density, and using your muscles to stop stomping which can hurt the joints, you can prevent bone loss by avoiding things that reduce bone density:

• Smoking
• Drugs that are known to greatly increase risk of bone fracture: stomach acid drugs and steroid anti-inflammatory drugs, regular use of SSRI antidepressants such as Prozac and Paxil. Numerous medications used to treat different cancers may produce osteopenia (bone shortage) and osteoporosis in long-term cancer survivors. See Stomach Acid Drugs Increase Osteoporosis and Hip Fractures
• Lack of sunlight. Calcium cannot be absorbed or do its job without enough sunlight
  
• High consumption of meat and dairy products
• Drinking alcohol too often
  
• Lack of fruit and vegetables, and vegetable calcium sources
• Eating wheat and related grains by people with celiac
  

Osteoporosis and osteopenia cause major problems for men, not only women. More on this to come. Move, walk, lift weights, stand on your hands, and jump for fun, exercise, and bone building. You do not need to ooze around on tiptoe to avoid impact injuries. Jump and dance and stamp your feet for fun, without jarring your joints and retinas loose. Have fun.

Carol ended her comment to me with, "Thanks for your site - I've learned a lot about alignment, which has helped in many ways." Thank you Carol for writing so many helpful questions for our benefit.

Labels: aerospace, biking, facet joints, fix pain, impact, injury, osteoporosis, plantar fasciitis, swimming

Permalink | 4 Comments| Email Post

Post your comment

Space Walks

The space shuttle Endeavour landed yesterday at Kennedy Space Center in Florida.

Endeavour's two-week assignment to the International Space Station was shortened for safety arrangements concerning Hurricane Dean.


The Endeavour name uses British spelling because it was named for the HMB Endeavour, a sailing ship commanded by 18th century explorer James Cook. Before launching the space shuttle Endeavour, NASA hung a humorous, quickly replaced "GO Endeavor" banner. The formal name is STS - Space Transportation System. This mission was STS-118.


During STS-118, crewmembers went outside the vehicle for assorted tasks. Going out is called extravehicular activity (EVA). Crew going on EVA wear pressurized suits to protect against radiation, space debris, temperature extremes, and low air pressure. The suits aren't just called suits, they are Extravehicular Mobility Units (EMUs). EVAs get interesting because EMUs are pressurized higher than the near vacuum of space, since space doesn't support human life, but not as much as inside the shuttle. The lower air pressure inside EMUs increases risk for various problems like gas embolism, but chiefly, decompression sickness, also called the bends.

Air pressure around us keeps nitrogen gas dissolved all over in our body all the time. When you go up a mountain, in a high airflight, or on an EVA, there is less surrounding pressure. Nitrogen becomes undissolved. If you reduce pressure slowly enough, nitrogen comes out peaceably and you can breathe it out. If you come up from a scuba dive or jump out for your EVA too fast, nitrogen offgases too fast, making bubbles, which are believed to be the basis of decompression sickness. Beside the role of exercise in countermeasures for space health and after returning, exercise is one of several factors affecting risk of decompression sickness. The post Exercise and Fitness in Decompression Sickness Risk explains.

If you could start an EVA with less nitrogen in your body, you could reduce your risk of decompression sickness. Crew preparing for an EVA do lengthy de-nitrogenation procedures. They breathe oxygen instead of air, and do physical exercise to "wash-out" nitrogen in several stages taking many hours. One goal of aviation scientists is to develop faster protocols for denitrogenation without increasing risk of decompression sickness during EVA.

American and Russian space programs use different denitrogenation protocols and different EVA suits. Russians use EMUs with higher suit pressure. The American suit design uses lower pressure, making it more flexible and maneuverable. The lower pressure suit is considered riskier for decompression sickness, and needs longer prebreathing and denitrogenation exercise. The Russian suit, higher pressure inside, is stiffer, needing more muscle to move. My Russian scientist friends say it is like the AK-47 - tough but good. My American scientist colleagues state that the Russian egress suit is a bull, lacking dexterity. My Russians reply they don't need it, as their vehicles, suits (and cosmonauts) are built strong and austerely, not needing fussy fine-tuning. Da.

My crew surgeon friends from both agencies are all submerged in triplicate paper forms for permissions to send me mission stories and photos to post for you. Nice that everyone can feel universally understood.

Labels: aerospace, altitude, scuba

Permalink | 0 Comments| Email Post

Post your comment

Altitude Sickness, Viagra, and Bubbles on Flights

The previous post Altitude Sickness During Flights told how certain symptoms occurring during air travel are from exposure to altitude.

If a craft were not pressurized, cabin pressure would be equivalent to the air pressure outside the aircraft at whatever altitude. At high altitude, there would not be enough air pressure inside for crew to be functional enough to fly. This was one of my areas of study with the Navy. Crew in unpressurized craft wear oxygen-delivery equipment.

Passenger planes are pressurized. The inside is kept at a higher pressure (lower equivalent altitude) than flight altitude (the air outside the plane). The pressure is still not as much as at sea level. Keeping that much interior pressure would create huge fuel costs and extreme metal fatigue on the craft. Regular passenger aircraft keep interior pressure equivalent to mild altitude exposure.

In the last few years, Viagra (sildenafil citrate) has been tested by various groups, including the military, as intervention against altitude sickness. Recently it was also found that the drug reduced symptoms, thought to be jet lag, after flights. My guess is that it was effective for symptoms from flights because of the same properties that may help reduce symptoms, in some, of altitude sickness.

Another component that I discovered many years ago in my work in altitude sickness, was a bubble component - an altogether new dimension to the altitude sickness puzzle. Decompression sickness bubbles can form in the body when coming up after a scuba dive. I found the same kind of bubbles can form in your body when going to elevations encountered in aircraft and mountain travel, with no prior scuba diving. More of this in future posts. Decompression sickness is also an issue when going into space during extra-vehicular activities. Click Space Walks.

Altitude sickness in flight is different from (or in addition to) the motion sickness of flight motion, or being stiff after not moving enough during long flights. The post Exercise and Stretch for Long Travel Sitting covers some exercises and stretches to relieve those problems.

Labels: aerospace, altitude, drugs, injury, scuba

Permalink | 0 Comments| Email Post

Post your comment

Exercise and Fitness in Decompression Sickness Risk

In the post Train Exercise is Exercise Training I mentioned the ongoing question in diving physiology research of how exercise can affect the risk of decompression sickness (the bends).

It seems that exercise done during a scuba dive at the bottom increases the amount of nitrogen gas you absorb from the air you breathe from your tanks. This makes more gas which could contribute to decompression sickness on the way up. Mild exercise on a "decompression hang" (waiting at specific shallower depths for a few minutes on the way up) seems to help let more gas dissolve out while you breathe, and may lower risk. Exercise soon after surfacing may increase gas coming out and increase risk according to other work. Some interesting studies look into whether exercise done days before a dive can reduce risk by "using up" specific components that decompression sickness bubbles need to be able to form. The kind of exercise and timing seems important. I will post more on this another time.

Some work looks at physical fitness, and whether that affects risk of decompression sickness (DCS). Would someone in better physical shape have lowered risk? What constitutes being in better shape? Is it body fat? Is it the amount of oxygen you can use to exercise? How might any one of those components affect DCS risk?

Here at the UHMS scientific meeting, one of the studies presented by French naval researchers is, "Does the VO2 max value predict the formation of intravascular circulating bubbles during decompression of healthy divers?" VO2 max (pronounced vee-oh-too-max) is the most oxygen you can use when doing the most exercise you can do. It is usually higher in people who can do more aerobic exercise (other factors also contribute). The maximum amount of exercise an average person can do is about ten times their resting level of oxygen use. Marathoners usually max at around 20 times better than resting levels. A top aerobic athlete can use about 30 times resting level (a horse - more than twice the top human max). Someone badly out of shape, or with heart disease or other problems that limit ability to get oxygen to cells, generally has a low VO2 max. You can raise your level with regular exercise at any age. It is not set.

In the French study, divers were tested for VO2 max a week before their experimental dive. They avoided any physical exercise 48 hours before the dive. Then half completed a dive in a dry hyperbaric chamber and the other half in the open sea with the same dive profile and decompression stop according to French military decompression table MN90. After the dive they were all tested for presence of small decompression bubbles in the bloodstream.

Bubbles can form in the body painlessly after a dive without creating decompression sickness. It is not the case that bubbles always form after every dive, as often thought. Certain bubbles can be detected audibly (they sound like pops and squeeks) using Doppler ultrasound, and other kinds of instruments being developed. I will post more another time about these bubbles and what ultrasound can and can't determine about bubbles and decompression sickness.

The French researchers found that bubble formation in both types of dive was related to the age and body mass index of the divers, but not to VO2max.

Being in good shape makes many aspects of diving safer, even if it doesn't affect risk of decompression sickness. Being in better aerobic shape helps you swim more easily against currents that may take you away from your dive site or boat. Strengthening your body through weightlifting with good body mechanics helps you lift and haul gear with less chance of injury, and practicing all your physical skills helps you be more able to rescue someone or yourself.

What about physical fitness and risk of decompression sickness in space? Several studies here at the meeting address that. Astronauts who go outside the space vehicle go to lower pressures, similar to divers coming up from a dive. Many considerations, including exercise, go into their preparation for that. The interesting story is posted in Space Walks.

Labels: aerobic, aerospace, hyperbaric, scuba

Permalink | 0 Comments| Email Post

Post your comment

Exercise and Medicine Underwater and at High Pressure

For the next week, I will be at scientific meeting of the Undersea and Hyperbaric Medical Society (UHMS). My colleagues attending are flight surgeons, SEAL team captains, commercial divers, submersible and submarine craft personnel from navies of many countries, and scientists from all over the world who study the science of what happens to the body when working under different pressures, temperatures, and breathing gases - at altitude, underwater, and in the specialized dry compartments to build bridges and structures deep underwater. There are also physicians, technicians, nurses, and aerospace scientists and astronauts who use hyperbaric chamber technology to prevent or treat specific non-diving conditions. Allied health workers, divers, and non-divers also attend.

Originally, we were the Undersea Medical Society (UMS). As use of high-pressure oxygen chambers to treat illnesses other than diving climbed, more sessions on how hyperbaric oxygen works (and doesn't work) were added. Wound healing increased in focus. In 1986, we became the Undersea and Hyperbaric Medical Society (UHMS). Forums, sometimes strangely heated for brainy, cool-headed scientists, are held about which conditions legitimately respond to hyperbaric oxygen treatment and which are felt not to have evidence (no matter how much we wish it would work and alleviate the suffering of the patients).

Some of the established benefits of hyperbaric oxygen and some uses that are not shown to be effective are explained in the post and comments of Does Hyperbaric Oxygen Help Exercise Ability?

The meeting will cover many interesting topics in decompression bubbles that are thought to cause (or be part of) decompression sickness, or "the bends," and mathematical and empirical models of decompression. Decompression theory and bubbles were my research area for many years along with the effects of too much oxygen on the body during exercise underwater and in dry habitats underwater. The meeting will have many sessions in clinical hyperbaric oxygen therapy for several specific conditions (abbreviated HBO, HBOT, HB02 and other), chamber equipment, and wound treatment. There will be a session of The Veterinary Hyperbaric Medicine Society. Animals get problem wounds that need help healing, too.

The national board exam for hyperbaric chamber nurse and technician will be administered. There is also a board exam for physicians in hyperbaric medicine held each fall through the American Board of Preventive Medicine & Emergency Medicine. Information and background on both exams is on the UHMS web site. I wrote the study guides for both exams. I tried to make them fun, user-friendly, and packed with understanding, not just lists of facts and equations to memorize. The guides cover the entire contents of both areas and are a nice review or compendium for anyone interested I the field. Info is on my web site books page.

I won't be staying at the fancy conference hotel but at a backpacker's hostel. Over the next week, I will try to get to Internet cafes to post on some of the interesting topics and research at the meeting - and swim and go underwater for real. That is good for a researcher in underwater exercise and medicine to do.


Here is the next post from the conference Hyperbarics for Diabetic Foot Injury.

Labels: aerospace, education, hyperbaric, injury, scuba

Permalink | 0 Comments| Email Post

Post your comment

Forensic Anthropology and Bone Density

A few weeks ago, I attended a lecture on forensic anthropology. In general, this is the study of things you can tell from human bones in a crime setting. How old was the person? Were they male or female? How big were they? What was their probable race or ancestry?

Why was I there when my work is with the living? Two main reasons. I am the science officer for the Vidocq Society, an international forensic society. I might evaluate data, for example in an aviation disaster, whether someone might have been conscious at each point when undergoing G-forces or different temperatures and amounts of oxygen after a depressurization at various altitudes. In a scuba death, I might advise on physical changes that occur with different situations. The second reason was to learn more about bones. Bones are remarkable. Your bones know a lot about you. What was your health like? Were you active? What kind of activity did you do? When I was small, I read about an archaeological dig in ancient Rome. The bones of a girl were recovered. The account stated they could tell she carried loads too heavy for her, and was therefore (in conjunction with other evidence) probably a servant or slave. I was riveted. How could they know that? I spent years after that learning more about telling how someone moved from looking at their bones.

Throughout your entire life, when you exercise you stimulate growth of new bone cells. The physical pull of muscles thickens your bones where the muscles attach. Using your arm muscles thickens arm bones. Using your legs strengthens leg bones, and so on. This is a main mechanism of how exercise prevents osteoporosis. Without exercise, you don't stimulate enough new cells to counter the normal loss as old ones break down. Your bones thin no matter how much calcium you eat. The post Exercise is More Important Than Calcium Supplements for Bones tells more about this. Bone demineralization is rapid and serious in astronauts in microgravity (Collapsing Astronaut Gives Healthy Reminder).

How you use your muscles causes them to pull differently, giving evidence about the kind of habitual motion. More interesting is that when you are active, your bones grow and shape themselves to facilitate your motion. An example of interest to readers following the posts on squatting is that people who habitually sit for normal daily life in full squat grow "squatting facets" on their lower leg bones. These are small areas on the bone that quickly grow to make squatting more comfortable. At one point, it was a debate in anthropology that squatting facets were a marker of someone of Asian ancestry, until it was found that others who squat also grow them, and that squatting facets disappear when the person adopts a Western sitting habit of chairs and no longer squats. Babies of all races can have them.

Someone who habitually slouches can change the shape of their bones, eventually deforming them. This can occur in the spine, knees, hips, ankles, shoulders, feet, toes - everywhere you pressure your bones. Changing positioning habits to healthier ones can, in many cases, reshape the bones back to healthier shape. Think of braces on your teeth. It's human bonsai. In cases of extreme dystrophies of the muscles, someone who sits without function of their trunk muscles to hold the spine upright, can eventually deform their spine until their ribs sit on their hip bones. How are you sitting right now? The recent post What Does Stretching Do? explained a bit of why stretching isn't reducing injuries. People are stretching, then exercising and going about daily life in bent over positions that rub and grind the joints and soft tissue.

You literally shape your own health. Use the posts throughout this Fitness Fixer blog to do healthy exercise in healthful positioning so that your bones will only tell good tales about you.

Labels: achilles stretch, aerospace, ankle, arm, feet, forensic, injury, leg stretch, osteoporosis, posture, scuba, sitting, squat, toes

Permalink | 1 Comments| Email Post

Post your comment

Collapsing Astronaut Gives Healthy Reminder

On Friday, a day after the shuttle Atlantis returned after 12 days at reduced gravity, one of the astronauts collapsed twice during the welcome home ceremony. The reasons are the same as what happens here on Earth.

When you stand and sit on Earth, some of your blood pools in the veins of your legs because of the pull of gravity. In space, the pull of gravity is weak so blood does not pool. Blood floats upward. Astronauts and mission control scientists refer to the upward shift of blood during space flight in a technical manner. They call it the "Fat-Face-Chicken-Legs-Effect."

Upon return to the gravity of Earth, blood is again pulled downward. More pooling than usual occurs and not enough blood may be able to get to the brain. It is not uncommon for astronauts to feel weak and dizzy.

You may notice the same venous pooling on land in several situations: Sometimes when you stand suddenly, the rush of pooling in legs briefly lowers blood supply and blood pressure to your head. You may feel light headed. When this happens you just need to bend over and get your head down. Lowering your head allows gravity to restore blood, relieving dizziness. Extreme pooling has caused occasional cases of fainting when standing suddenly, when standing long periods at attention, and when climbing out of the water, especially hot water in spas and hot tubs. Pooling has been fatal to beached whales.

In space, the human body quickly gets badly out of shape without the pull of gravity. Muscles do not have to work to pull bones and quickly weaken. Bones do not have the muscular pull they need to stay dense and lose much calcium and bone mineral. Astronauts lose bone in space no matter how much calcium they eat. The cardiovascular system does not have to work as much to pump blood. This is why astronauts must exercise so much during missions.

Here on Earth you need regular activity that contracts leg and other muscles to squeeze the vessels to keep blood moving. After sitting for long periods at work and on a plane, your feet may swell with pooling fluids. Contracting your leg muscles while sitting, and by getting up and moving around pumps blood upward, reducing pooling and your risk of clots. For daily life, you need activity to keep muscles and bones from weakening. Even if you are sick it is crucial to get up and out of bed every day to stop the huge health losses that occur. Being sedentary is so devastating to health that bed rest is used as a model in scientific studies for loss of many health benchmarks in the microgravity of space. Stand to exercise, get outside, and enjoy some fun activity every day. Smile - another way to exercise against gravity.

Gravity and activity are important for health. Thank the astronaut, Heidemarie Stefanyshyn-Piper, for reminding us.

Labels: aerospace, circulation, osteoporosis, strength

Permalink | 0 Comments| Email Post

Post your comment