Maximizing Your Potential: Hemoglobin and Oxygen Delivery

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.