Maximizing Your Potential: Hemoglobin and Oxygen Delivery

Marginal gains. The term “marginal gains” is being heard more and more in the world of sports. The concept of marginal gains is simple. What are the little (marginal) things you can improve that cumulatively result in overall performance improvements? As a performance adviser to many of the
world’s top endurance athletes, it is my job to identify where marginal gains can be made physiologically. One focus is oxygen availability, and a key player is hemoglobin, a protein in red blood cells. Hemoglobin is a micro-sized protein that has macro-sized effects on performance. And what you eat on a daily basis can affect hemoglobin levels.

Put simply, endurance exercise is largely characterized by a simple requirement; sustaining repeated muscle contraction. This criterion is
fulfilled via two basic functions, the ability to consume enough oxygen and adequate fueling. Regarding fueling, that is another topic, however summarized by simply providing the right fuels at the right time during activity. Regarding oxygen, the process is a bit more complex.
Muscles require oxygen to convert sugars into energy. In the absence of replenishing oxygen, muscles reach complete exhaustion in just a few
minutes. Therefore, endurance athletes require constant oxygen delivery to the muscles. It is hemoglobin that carries oxygen to the muscles.
Hemoglobin picks up oxygen in the lungs and delivers it to the tissues of the body, most notably your muscles. Hemoglobin levels have a direct
impact on endurance exercise performance. Lower levels of hemoglobin causes decreased efficiency of oxygen delivery to the muscles. The result is more rapid muscle fatigue, decreased VO2max, and higher heart rates. As a dramatic example, if you have ever exercised at high altitude, you know what it feels like to have less oxygen delivered to the muscles.

Certain micronutrients are essential in the formation of hemoglobin. Because of the high turnover rate of red blood cells and hemoglobin in endurance athletes, the dietary requirements of these micronutrients are higher than the average person. Failing to replenish them can result in a decrease in hemoglobin production, and thus performance.
Iron, folate, and vitamin B12 are directly involved in hemoglobin formation. Other micronutrients, such as vitamin B9, vitamin C, copper,
and vitamin A are indirectly involved in hemoglobin formation. Although the goal in replenishing micronutrients should be through dietary means, many athletes require supplementation at some point in the season.
To put this in an easily understood context, let me share a real-life case study.
A pro triathlete presents for routine monitoring. She has transitioned over the last nine months from the ITU circuit to the Ironman 70.3 and Ironman distances. She has been tolerating the training well and does not have complaints. Being new to the higher volume she does not know what to expect.

Blood work revealed low-normal hemoglobin (12.0), hematocrit (36.2), small platelets (MPV 6.5), and borderline large red blood cells (MCV 99.7). These findings are consistent with her prior test results during training. Micronutrients were tested as well and revealed a mild functional folate deficiency (within the low limits of the “normal range”, but given the high turnover rate of folate in a female endurance athlete her levels indicate a deficiency in these circumstances).

Intervention included significantly increasing dietary intake of folate and two weeks of supplementation. Follow up tests were performed each week for the following four weeks.

Follow-up #1: Folate
16.2, Hemoglobin 12.4, Hematocrit 37.7
Follow-up #2: Folate
18.8, Hemoglobin 12.7, Hematocrit 38.2
Follow-up #3: Folate
>20.0, Hemoglobin 13.1, Hematocrit 40.4
Follow-up #4: Folate
>20.0, Hemoglobin 14.2, Hematocrit 44.8 (following 5 days of taper)

There is little doubt that the 15% increase in hemoglobin achieved in the case study above will result in improved performance, and this
particular athlete’s performance last year confirms. In this example we must consider the effects of coming from sea level to 5,600 feet of elevation. However, these changes significantly exceed what would be expected for acclimation at this elevation, and the red blood cell indices were highly suggestive of a folate repletion effect being the primary driver behind the improvements. Thus, much of this change was the result of simply making an adequate amount of micronutrients available to keep up with the high turnover of red blood cells, and thus hemoglobin.
As an endurance athlete, your dietary requirements of
certain micronutrients are increased. Regarding oxygen delivery to the muscles,
iron, folate, vitamins B9 and B12, vitamin C, copper, and vitamin A are
critical to optimizing hemoglobin levels. Be sure you are eating ample amounts
of foods high in these micronutrients. Doing so will aid in optimal oxygen
delivery to the muscles, and thus help you perform at your highest potential.
The following table shows foods high in each of these
essential micronutrients.

Iron
Folate
(Vitamin B9)
Vitamin
B12
Red Meat
Beans and Lentils
Fish
Egg Yolks
Dark, Leafy Greens
Red Meat
Dark, Leafy Greens
Asparagus and Broccoli
Cheese
Dried Fruit
Romaine Lettuce
Eggs
Beans and Lentils
Avocado
Yogurt and Milk
Tuna
Oranges and Tropical Fruits
Fortified Vegan Products
Vitamin
B6
Copper
Vitamin
C
Bran
Sunflower and Sesame Seeds
Peppers (Chili and Bell)
Pistachios
Nuts
Dark, Leafy Greens
Garlic
Cocoa Powder
Broccoli and Cauliflower
Fish
Sundried Tomatoes
Fruits
Sunflower and Sesame Seeds
Calamari and Lobster
Thyme and Parsley
Hazelnuts
Dried Herbs
Pine Teas

Why Eating Disorders In Endurance Athletes Are Especially Dangerous

It is time for those of us involved in endurance sports to bring attention to the problem of eating disorders in endurance athletes. I hope you will help address this problem by sharing this post with every runner, triathlete, and cyclist you know. Thank you.

The topic of eating disorders in endurance athletes is too often neglected. The numbers are staggering. Studies show that up to 25% of female and 10% of male endurance athletes have either a subclinical or clinical eating disorder. In a population dominated by highly motivated, highly disciplined, perfectionist personalities, we are all at risk of developing an eating disorder. Yet, it continues on without much attention, and in fact often unintentionally persuaded through publications talking about lighter being faster, ideal race weight, and on and on.

Even more staggering than the frequency are the long term implications of eating disorders in endurance athletes, especially when they occur during adolescence.

Eating disorders in endurance athletes tend to be different. Although plenty fall in line with the classic definitions of specific eating disorders, many do not. For example, excessive exercise is simply part of training, not a “sign” of an eating disorder. Endurance athletes must eat to train, and rarely is prolonged anorexia a problem. Athletes eat. Most often, an “eating disorder” in an endurance athlete is simply inadequate fueling during training. But, where is that line?

Eating disorders cause problems in endurance athletes. Stress fractures, hormone disorders, poor bone development, malabsorption, and micronutrient deficiencies are just some of them. They also can cause significant health problems later in life, such as osteoporosis and hip fractures, which substantially increase the risk of death and major morbidity. The biggest problem with eating disorders is that many of the consequences don’t present until long after the eating disorder is corrected. The treatment is prevention.

Some of the Long Term Consequences of Eating Disorders In Endurance Athletes

Bone Mass

The most critical period of bone mass development is adolescent years to late teens/early twenties. During this time, your body is rapidly increasing bone mass to keep up with growth. If bone mass development is compromised, such as in cases of malnutrition due to eating disorders, peak bone mass will be reduced. The consequences are significantly increased risk for stress fractures throughout the span of the athletic years, and risk for osteoporosis later in life. Osteoporosis greatly increases the risk of fractures, physical deformity, organ compression, chronic pain, and overall morbidity and mortality. Hip fractures, one of the most well-known consequences of osteoporosis, have a 15-37% 1 year mortality rate in people over age 65.

Hormone Disorders
Studies show that inadequate fueling amidst excessive exercise can reduce thyroid function. This may occur by way of impacting adrenal function, and thus cortisol levels, or it may be secondary to reduced dietary fat and/or reduced body fat. Science has posed and supported all of these pathways, however they all lead to one causative factor, inadequate fueling (eating disorder) during training. Hormones are critical to our well-being, and performance. The types of hormone disorders sparked by inadequate fueling during training can cause excessive fatigue, decreased muscle recovery (by way of the HPA axis and growth hormone), mood swings, sleep problems, compromised immunity, and more. 
Malnutrition
Malnutrition has far reaching consequences. For the sake of keeping this article short, let’s just address one thing that matters much to athletes, performance. Nutrients are what keep our cells going. A deficiency in intake often leads to a deficiency in function. For example, for red blood cells to replicate, iron, B12, folate, and several other micronutrients are essential. Red blood cells are destroyed at high rates in training endurance athletes. In response, your body will produce new cells. If the necessary micronutrients are not readily available, the process of new red blood cell production will be limited, which can result in fatigue, decreased performance, and anemia. The citric acid cycle (or Kreb’s cycle) is driven by micronutrients. These are just two examples of many. There are countless pathways critical to performance that rely 100% on the availability of micronutrients. And for that matter…life relies 100% on it as well. 
Absorption Problems and Food Sensitivities?
I typically prefer to stick to writing scientific supported information. However, in my experience working with professional, elite, and recreational endurance athletes, I have noted an interesting correlation between past eating disorders and current micronutrient absorption problems and often food sensitivities. I have yet to find any research on this (if you have please share it!), yet the correlation is so strong that I feel confident in sharing it.
Summary
Eating disorders ruin careers. They have far-reaching effects that follow people long after recovery, especially athletes.The predisposition for eating disorders in endurance athletes is strong. There are many reasons endurance athletes might develop eating disorders, ranging from body image to performance. While the tendency is to attempt to address the “underlying problem” (via counseling), doing so is complicated, as it varies per individual. However, I believe that by making the long term consequences of eating disorders in endurance athletes known, we can reduce the incidence. It is working with smoking. We have reduced smoking from 42% of adults in 1965 to 19% of adults in 2011. Eating disorders in endurance athletes can have implications nearly as serious as smoking. 

An eating disorder in an endurance athlete is often unidentifiable. Athletes eat. By definition, an eating disorder in an athlete simply means inadequate fueling during training. There are very few circumstances when an athlete increasing training should be concurrently dieting. If this is a desired combination, it should be done under careful monitoring by a health care professional familiar with the dangers of dieting while training.