Low bone mineral density and Stress Fractures in Endurance Athletes
There seem to be more stress fractures happening nowadays
My impression is that stress fractures among endurance athletes are more freequent because more people than ever are seeking our assistance with this injury. I am not alone in having this opinion.
Take a few minutes later to read some of the research here about the incidence of stress fractures in athletes.
Image: Fit Kiwi ably demonstrating the "Lift & Press", the best bone-building exercise there is
What are stress fractures?
A stress fracture is a crack in the bone, caused by repeated stress that exceeds the rate of repair and strengthening which is the normal response to repeated compression, bending and twisting pressures on the bone. Think of a stress fracture as being like what happens to a wire that progressively weakens (metal fatigue), then finally breaks in two, when it is repeatedly bent back and forth.
For a more detailed explanation, please read this article written for stress fracture patients. Its a good article but far too light on the nutrition side of things which is so important for making a quick and full recovery.
Back in the"good old days", stress fractures were seen mostly in athletes doing daily extreme exercise, such as running 100 miles, or more, in a week (100 miles a week was a training target, for a few weeks at a time, during a training phase, for many Lydiard Method trained runners during the 60's and 70's and few suffered stress fractures).
What is rather disturbing nowadays is the majority of stress fracture cases coming to our attention are being suffered by runners and triathletes who may be doing as little as 30 kilometers of running a week. Stress fractures are occasionally seen in swimmers and cyclists. You wouldn't think swimming and cycling can cause stress fractures, but they do, usually affecting the pelvis and lumbar spine.
By the way, the last swimming-related stress fracture I got to see was in a young male swimmer with a lumbar spine stress fracture. The solution was a coaching one and involved cleaning up his tumble turns.
This article tries to answer the question, "Why?" and outline the measures we can all take to ensure we have strong bones.
It is thought that some forms of exercise are no good for increasing bone strength
Moderate exercise, including running, cycling and swimming will help produce and maintain strong bones, perhaps as effectively as regular weight training. However, there is still the widespread view among many health and fitness experts that non weight-bearing exercises, such as swimming and cycling, do not promote bone strength. There is also the contradiction that stress fractures are more common in distance runners, mostly females. If running builds bone, then how come so many runners suffer stress fractures and often have bone scan results that show low bone mineral density? (I'll explain in this article why the answer is more complicated than just too much running).
It is not uncommon for distance runners, cyclists and other endurance athletes, to have low mineral density of bones like the heel, shin, hips, pelvis and spine and for this to have no obvious association between sporting type or nutrition. The only obvious common factor is endurance training and possibly under-eating. Its not that simple. I'll try to explain as best I can what I think is going on and offer solutions. What you will learn is that there is no single "fix", such as a wonder drug, nutrient or exercise, like abdominal exercises or futilely trying to "engage your glutes". The solution is getting a complex mix of factors in balance while eliminating others altogether, or as best as one can.
Image: Fit Kiwi once again demonstrating near perfect technique. Yes, Fit Kiwi can swim!
Why do many experts believe that swimming and cycling do not build strong bones?
The belief that cycling and swimming do not build bone and may actually cause low bone density is misplaced. This belief prevails due to a number of studies of elite cyclists and swimmers that found the paradox of low bone density in these athletes. At the time of these studies it seemed obvious, if you want to study the effects of cycling on bone density, then you might as well study professional cyclists, rather than recreational ones. To their great surprise, it was found that the professional cyclists had low bone density as compared to recreational cyclist and sedentary people.
The hypothesis, to explain this unexpected finding, was that bones need the stress of gravity bearing down upon them during exercise in order to stimulate bone strengthening. This view was supported by studies of bone density in astronauts. "Fair enough", you may think, but there was one major oversight with these studies.
The researchers failed to take account of the widespread legitimate and illegitimate use of steroids, including inhaled asthma medication.
Asthma medication is in widespread use among these athletes, whether they are truly asthmatic or not. These drugs are beneficial for performance and recovery, so many athletes wising to gain the competitive edge, or just trying to keep up with the competition who are abusing steroids, resort to steroids, either illegally, or by getting a questionable medical exemption for their use.
Much of the steroid use by these athletes may never be admitted to, even if the researchers thought to ask, and therefore this is one most important factor that was overlooked by osteoporosis researchers. Long term use of these drugs drains the body and bones of calcium which no amount of beneficial exercise can ever compensate for.
The researchers also failed to consider the consequences of prolonged stress and exhaustion as well as the finer details of diet (more about these later).
Asthma drugs, steroids and the epidemic of osteoporosis and arthritis
The widespread prescribing of steroids, particularly for asthma, is one explanation for why we have a growing epidemic of osteoporosis and arthritis in the general population some 20-30 years after these drugs came into widespread use. In my opinion most of this prescribing of steroids as being excessive and often irresponsible. The majority of asthma cases can be successfully remedied by non-drugs methods, including teaching a person how to breathe in a healthy way.
The tsunami wave of bone diseases that are hitting us today, along with companion diseases such as hypothyroidism, anxiety, depression, "brain fog", adrenal fatigue, gall bladder disease, bowell disease, cardiovascular disease (arteriosclerosis), most autoimmune diseases and chronic fatigue, coincides as the first generation of medicated asthmatics from the '70's and 80's hit middle age. All steroids, including Prednisone and the drugs group of antihistamines, have similar effects of draining the body of calcium. Similar patterns exist with other meds, such as those commonly prescribed for high blood pressure and depression. Please refer here for more about steroids, asthma and osteoporosis.
Chronic stress and bone loss
When a person is stressed, the adrenal glands respond by injecting a squirt of multiple stress hormones, including cortisol, into the circulation. This initiates the "Fight or Flight Response", or "General Adaptation Syndrome" model, as first described by Dr Hans Selye in the 1950's when he conducted experiments on laboratory animals. The dear Dr Selye tortured the animals daily by administering progressively stronger electric shocks, while monitoring their behavioural and physiological responses, all of which were ultimately negative to eventually being deadly!
Please take a few minutes to watch this short lesson that describes Dr Selye's general adaptation syndrome model
Endurance training for many hours, day after day, is frankly too stressful for any creature, including Humans, to handle, stimulating either chronic elevated levels of cortisol, or frequent periods of elevated cortisol followed by long periods of low cortisol, or chronically low levels (the latter two being known as the "Tired Athlete"). This condition is best referred as "adrenal fatigue" a term first described by Dr James Wilson. You can learn more about adrenal fatigue at this excellent website.
The two images below, show a laboratory test that confirms this person has "adrenal fatigue". The readings show normal cortisol levels in the morning. However, as the day progresses, the subject is unable to maintain anything near adequate cortisol levels and is consequently feeling dead tired by mid afternoon. This is the profile one typically sees in burned out athletes who suffer recurrent injuries, who seem to catch every illness, who heal slowly and poorly and who may present with thyroid and other hormone related issues. The lowest testosterone levels I have ever seen in males have been in exhausted triathlete and Iron Man athletes.
Cortisol (cortisone) is, of course, the original steroid, produced by the cortex of the adrenal glands, is how pharmaceutical versions, such as Prednisone and Fludrocortisone, get their names. Cortisol is necessary for the regulation of inflammation and aiding healing, but it is not healthy at all, if constantly elevated, or wildly fluctuating from high to low. As with any steroid hormone, when in excess, cortisone drains calcium and other minerals from the bones, hence the link between chronic stress and bone loss.
Elevated cortisol, or big daily spikes may explain the low bone density seen in over trained and exhausted athletes.
Of course, there are additional factors, such as, poor body mechanics. It usually turns out there is a poor diet, including the consumption of acidic sports and energy drinks (more about these later), most often empty calories and not much else. As many as 90% of New Zealanders have low vitamin D levels. There may even be the presence of heavy metals such as lead and arsenic which eat away bone and cartilage. With any, or all of these going on, there will be progressive bone loss as the months turn into years.
Image: Fit Kiwi furiously preparing for the Round Taupo Cycle Race
Chronic, exhausting exercise and bone loss
Exercise produces acidic byproducts. This is normal and the body has effective mechanism to maintain near perfect body PH at a slightly alkaline PH 7.4. The principal mechanism for this is the shifting of alkaline calcium between the bones and the soft tissues, including the circulation. So, during any form of intense exercise, when there is the production of acidic byproducts, such as lactic acid, calcium is temporarily shifted from the bones into the circulation. This is fine, so long as it is balanced by long periods during which the process is in the reverse direction and calcium shifts from soft tissues to bone.
This may explain, in part, why we see bone mineral loss in chronic long distance athletes and not in athletes who do their exercise in short bursts of intensity with relatively long periods of rest between workouts.
Vitamin D deficiency in athletes
Its harder to get a vitamin D blood test via your doctor nowadays. I had the benefit of reviewing many and continue to do so. We know that low vitamin D levels contribute to many diseases, including osteoporosis and related conditions such as hypothyroidism.
One assumes that athletes, such as runners and cyclists will have high levels of vitamin D, since they are exercising in the sun most days. This is not true. My experience is that most athletes, including runners and cyclists can have very low levels. How can this be?
Most athletes train at the beginning and ends of the day, times when solar UV is very low. In addition, they cover up to keep warm since these are the colder times of day. If the sun is out, then they will slop on the sunscreen. I also suspect that athletes who train very hard have higher requirements for vitamin D, as is the case for all other nutrients.
Hypothyroidism and bone loss
The thyroid gland and the parathyroid gland strike a delicate balance that regulates the shift of calcium between the bones and the soft tissues, including circulation. If the thyroid is weak and damaged then the parathyroid gland becomes dominant relative to the thyroid. Other than fatigue, weight gain, depression and brain fog, there is also the subtle loss of calcium from the bones and its deposition in soft tissues. This may partly explain why dry and brittle (chalky) hair, skin (dermatitis) and nails and fibromyalgia are very closely associated with thyroid problems.
The medical solution to parathyroid dominance is to remove the parathyroid which is a really stupid measure because it commits the patient to a life-long dependence on hormone therapy that gradually loses effectiveness, while bone loss continues. Surely, the better move is to heal the thyroid and adrenal glands? (the adrenals have a profound effect in the thyroid and vice-versa).
Image: progressive loss of bone, often associated with thyroid issues, leading to the gradual collapse of the spine, particularly affecting the thoracic region
Inflammation and the bone connection
Inflammation is an essential survival mechanism. Without it we get sick and die. Inflammation is our body fighting infection. It musters the healing processes, after infection and trauma. When it is at work in the body, it is not unlike a very busy work site. This frenetic activity explains the heat and swelling.
Learn more about inflammation and healing and also why you are advised to avoid anti-inflammatory drugs by reading this article about inflammation.
Inflammation is regulated by the adrenal glands that squirt out nano-levels of signalling steroidal hormones, principally cortisol. Cortisol is kind of like the Senior Building Site Supervisor. When it does its job right, wonderfully orchestrated processes of healing are undertaken by millions of furiously busy artisans, each assigned with their special roles. If adrenal function is dysfunctional, there is work site chaos of the First Order. This chaos is experienced as chronic and out of control inflammation and poor healing. If cortisol is very low, or fluctuating wildly, the person may also suffer allergies such as, asthma, hives, Lupus and food sensitivities.
Inflammation that is out of control is acid-forming in the body which leads to the shifting of calcium from the bones into the soft tissues to neutralise the acidity. We