Blood Testing - should you do it?

The Importance of Biannual Blood Testing

If you exercise, maintaining optimal internal health is essential for achieving peak performance and recovery. While training plans and nutrition strategies often dominate discussions, they cannot fully account for what is happening beneath the surface: an athlete's internal physiology. Regular blood testing provides a clear picture of this internal health, allowing athletes to identify deficiencies, monitor training stress, and personalize their nutrition and recovery plans.

At Fuelin, we recommend biannual blood testing in October/November and April/May. These strategic timeframes align with seasonal transitions and training cycles, offering the most actionable insights into your health.

Why Blood Testing Matters

Blood tests allow for the monitoring of critical biomarkers that will impact your health, energy production, recovery, and overall performance. A few typical marker examples include:

Vitamin D: Supports bone health, immune function, and muscle recovery.
Full Iron Panel: Critical for oxygen transport and energy production.
HbA1c: Indicates long-term blood glucose control and energy metabolism.

Key Biomarkers: Examples and Their Implications

Vitamin D

Vitamin D is essential for everyone, as it plays a significant role in muscle function, bone structure, immune health, and brain health. Despite its importance, many athletes are deficient due to limited sun exposure or insufficient dietary intake.

Deficiency: <20 ng/mL
Symptoms: Fatigue, muscle weakness, increased risk of stress fractures.
Intervention: Targeted supplementation (e.g., 5,000 - 10,000IU/day Monday to Friday for up to 12 weeks) under supervision.

Insufficiency: 20-40 ng/mL
Symptoms: Suboptimal recovery, weakened immunity.
Intervention: Targeted supplementation (2,000 - 5,000 IU/day Monday to Friday for up to 12 weeks) and dietary adjustments.

Optimal Levels: 41-70 ng/mL
Benefits: Enhanced recovery, reduced injury risk, improved performance, enhanced mood.

Testing vitamin D in October/November is particularly valuable, as levels tend to drop after summer, especially in athletes training indoors or in northern climates. Being aware of your levels going into Winter will be invaluable to ensure deficiency does not extend into those months.

Full Iron Panel

Iron is vital for oxygen transport and energy production. The full iron panel includes ferritin (F)), Total Iron Binding Capacity (TIBC), and transferrin saturation (TS). Haemoglobin (Hb)and Hematocrit (HC) are part of a full blood count and used to determine iron status in conjunction with these markers.

Ferritin:

Deficiency = F<30 ng/L, Hb >115 ng/dL, TS >16% 
Deficiency, non-anaemia = F <20, Hb >115, TS >16%
Deficiency, anaemia = F <12, Hb <115, TS <16%
Symptoms: Fatigue, poor performance, difficulty maintaining training intensity, erratic performance
Intervention: Iron supplementation (e.g., ferrous sulfate 100-200mg/day elemental iron on alternate days with 100mg vitamin C) and increased dietary iron from sources like red meat, spinach, and lentils.

Insufficiency: 30-50 ng/mL
Symptoms: Reduced endurance capacity, Fatigue
Intervention: Monitor and consider light supplementation Iron supplementation (e.g., ferrous sulfate 100mg/day elemental iron on alternate days with 100mg vitamin C) alongside iron-rich foods.

Optimal Levels: 50-150 ng/mL for women, 100-300 ng/mL for men.
Iron testing in April/May is crucial, as intense winter training can deplete iron stores, particularly in female athletes.

HbA1c (Hemoglobin A1c)

HbA1c reflects average blood glucose levels over the past 90 days. It is a marker of metabolic health and glucose control. For everyone including endurance athletes, stable blood glucose is critical for health reflecting your body's ability to manage carbohydrates.

Normal Range: <5.7%
Benefits: Indicates good glucose control, reduced risk of insulin resistance.

Pre-Diabetic Range: 5.7-6.4%
Risks: Impaired glucose tolerance, reduced endurance.
Intervention: Evaluate carbohydrate timing, reduce processed sugar intake, resistance training and increase activity levels.

Diabetic Range: >/= 6.5%
Risks: Poor recovery, increased inflammation, and long-term health risks.
Intervention: Consult a healthcare professional for dietary and lifestyle changes. Evaluate carbohydrate timing, reduce processed sugar intake, resistance training and increase activity levels.

For athletes, elevated HbA1c could indicate insufficient carbohydrate utilization or a surplus of total calories including refined carbohydrates.

Timing of Blood Tests: October/November and April/May

The recommendation to test in October/November and April/May aligns with the natural ebbs and flows of an athlete's training and competition cycles:

October/November:

Transition from peak season to off-season. (Northern Hemisphere)
Preparatory phase for summer racing and peak training loads.  (Southern Hemisphere)
Identify post-season deficiencies and recovery needs.

April/May:

Preparatory phase for summer racing and peak training loads. (Northern Hemisphere)
Transition from mid season to peak-season and then off-season. (Southern Hemisphere)
Identify post-season deficiencies and recovery needs.
Monitor recovery metrics post-intense winter training.

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By testing at these intervals, it is possible to detect deficiencies, insufficiency or excesses and implement corrective strategies ahead of critical training periods. Corrective strategies will involve habit formation around food and targeted supplementation when required.

Case Studies: Practical Applications

‍Case 1: Vitamin D Deficiency

Fuelin Member: Female triathlete, aged 34, based in a northern climate.
October Blood Test: Vitamin D = 18 ng/mL (deficient).
Intervention: Supplementation with 10,000IU/day Monday to Friday for up to 12 weeks) under supervision and increased dietary intake through fortified foods.
Follow Up Blood Test 8 weeks later: Vitamin D = 63 ng/mL (optimal).
Result: Optimal levels. Subjectively athlete felt it improved recovery times, improved mood over winter and reduced susceptibility to colds during winter training.

Case 2: Iron Insufficiency

Fuelin Member: Male ultramarathoner, aged 42, preparing for a spring race.
October Blood Test: F 18 ng/L, Hb >115 ng/dL, TS >16% (non-anaemic deficiency)
Intervention: Increased red meat intake to twice per week, added vitamin C in form of daily orange and cup of berries to enhance absorption, and prescribed 200 mg/day of elemental iron (ferrous sulphate).Taken at night to avoid dairy and caffeine.
Follow Up Blood Test 8 weeks later: Ferritin = 75 ng/mL (optimal).
Result: Subjectively athlete felt enhanced energy levels. Objectively, improved training capacity (watts measured), and consistency in training.

Case 3: Elevated HbA1c

Fuelin Member: Male cyclist, aged 29, with high training volume.
April Blood Test: HbA1c = 5.9% (pre-diabetic range).
Intervention: Increased protein intake. Adjusted carb timing to fuel rides in line with more zone 2 training prescribed by coach. Improved carbohydrate quality on day to day basis including increased focus on eating minimu 6 serves of vegetables per day and two pieces of fruit. Fiber intake targeted at 30g/day.
Follow Up Blood Test 12 weeks later:: HbA1c reduced to 5.5% by October.
Result: Increased endurance and reduced post-training fatigue.

Benefits of Regular Testing

By incorporating blood testing into their routine, athletes gain several advantages:

- Personalized Nutrition: Tailor macronutrient and micronutrient intake to meet individual needs.
- Injury and Illness Prevention: Identify and address deficiencies before they impact health and performance.
- Training Optimization: Align physiological markers with training loads for maximum adaptation.
- Long-Term Health Monitoring: Detect potential chronic conditions early, ensuring longevity in sport.

Key Takeaways:

Regular Blood Testing for Everyone including athletes (exercising individuals): Conducting biannual blood tests in October/November and April/May provides essential insights into critical health markers such as vitamin D, iron, and HbA1c. Monitoring these markers ensures you can optimize performance, detect issues early, and refine nutrition and training plans.

Targeted Metrics for Health and Performance: Understanding optimal ranges for key biomarkers like vitamin D (30-50 ng/mL), ferritin (30-300 ng/mL), and HbA1c (<5.7%) is critical. These are only a few examples of markers that Fuelin recommends to get assessed. This allows you to address deficiencies and maintain peak health throughout the year.

Conclusion

As Chief Nutrition Officer of Fuelin, I advocate for regular blood testing as a cornerstone of everyone's health and performance. Testing in October/November and April/May allows everyone to track critical biomarkers such as vitamin D, iron status, and HbA1c at pivotal points in their training cycles. These insights enable you to implement targeted interventions, enhancing recovery, performance, and long-term health.

By taking a proactive approach to internal health, everyone including endurance athletes can unlock their full potential and stay ahead of the competition.

Thanks for reading.

Scott