Nutrition and Breathing Performance: The Overlooked Connection

•By Sarah Kim, Sports Nutritionist & Registered Dietitian

You optimize your training. You dial in your sleep. You invest in breathing equipment.

Then you eat foods that inflame your airways and reduce oxygen-carrying capacity.

Here's the nutrition-breathing connection every combat athlete should understand.

Iron: The Oxygen Transport System

Why It Matters

Iron is a core component of hemoglobin, the protein in red blood cells that binds and transports oxygen.

No iron = impaired hemoglobin production = reduced oxygen-carrying capacity = performance degradation.

The math is straightforward: If your hemoglobin is low, you're competing with a structural disadvantage in oxygen delivery.

The Combat Athlete Challenge

High training volume increases iron loss through:

  • Sweat (contains iron)
  • Foot-strike hemolysis (red blood cell damage from impact)
  • Inflammation (reduces iron absorption from gut)
  • Menstrual losses (female athletes particularly at risk)

Studies show 15-35% of endurance athletes have depleted iron stores even without frank anemia.

Confidence level: High. Iron's role in oxygen transport and deficiency prevalence in athletes is extensively documented.

Solution Protocol

Dietary iron sources:

  • Red meat 2-3x per week (heme iron, highly bioavailable)
  • Dark leafy greens daily (non-heme iron, pair with vitamin C for absorption)
  • Legumes, fortified grains

Absorption optimization:

  • Pair plant-based iron with vitamin C (e.g., spinach salad with citrus dressing)
  • Avoid coffee/tea within 1 hour of iron-rich meals (tannins inhibit absorption)
  • Cook in cast-iron pans (increases iron content of food)

Testing and supplementation:

Get ferritin levels tested if you experience persistent fatigue despite adequate sleep/training volume.

Target: Ferritin >30 ng/mL (minimum), >50 ng/mL (optimal for athletes)

If deficient, supplement under medical supervision (excessive iron is toxic).

Confidence level: High for dietary strategies. High for supplementation IF deficient (don't supplement without testing).

Inflammation and Airway Function

The Problem

Chronic systemic inflammation from poor diet can manifest as:

  • Inflamed nasal passages (increased airway resistance)
  • Reduced lung function
  • Exercise-induced bronchoconstriction
  • Slower recovery between training sessions

Essentially, you're creating internal resistance to oxygen flow.

Anti-Inflammatory Nutrition Strategy

Foods that reduce inflammation:

  • Fatty fish (salmon, mackerel, sardines): High in omega-3s (EPA/DHA)
  • Berries (blueberries, strawberries): Anthocyanins and polyphenols
  • Leafy greens (kale, spinach, arugula): Antioxidants and micronutrients
  • Turmeric: Curcumin (pair with black pepper for absorption)
  • Ginger: Gingerols (anti-inflammatory compounds)
  • Extra virgin olive oil: Oleocanthal (anti-inflammatory polyphenol)

Foods that promote inflammation:

  • Excess added sugar (creates inflammatory signaling)
  • Processed foods high in omega-6 oils (corn, soybean, vegetable oil)
  • Trans fats (inflammatory and harmful to cardiovascular health)
  • Excess alcohol (inflammatory and dehydrating)

Confidence level: High for omega-3 anti-inflammatory effects. Medium for specific food impacts on respiratory function (mechanism is sound, direct research in athletes is limited).

Hydration and Mucus Viscosity

The Mechanism

Adequate hydration maintains thin, easily-cleared mucus in nasal passages and airways.

Dehydration thickens mucus, which:

  • Physically obstructs airflow
  • Reduces mucociliary clearance (your body's natural airway cleaning system)
  • Increases nasal resistance

Even 2% dehydration (roughly 3 lbs fluid loss for a 150-lb athlete) measurably impairs respiratory efficiency.

Hydration Protocol

Baseline daily intake:

Half your bodyweight (lbs) in ounces of water

Example: 160-lb athlete → 80oz (10 cups) water daily

Add for training:

16-24oz per hour of training

Add for environmental factors:

Extra 16-24oz if training in hot/humid conditions or at altitude

Timing strategy:

  • Consistent intake throughout day (not chugging 60oz in one sitting)
  • Pale yellow urine = adequate (dark yellow = dehydrated, clear = possibly overhydrated)

Electrolytes:

If training 90+ minutes or in hot conditions, add sodium and potassium (commercial sports drinks, electrolyte tablets, or whole food sources like bananas and pickles).

Confidence level: High. Hydration's effect on performance and physiological function is extremely well-established.

Carbohydrates and Respiratory Efficiency

The Science

Carbohydrates are more oxygen-efficient than fats for high-intensity work.

Your body requires less oxygen to generate the same ATP from carbohydrates compared to fats.

Specifically: Respiratory quotient (RQ) for carbs ≈ 1.0, for fats ≈ 0.7. Higher RQ = more CO2 produced per O2 consumed, but also more ATP generated per liter of oxygen.

Translation: At high intensities (where oxygen becomes limiting), carb-fueled metabolism is more efficient.

Confidence level: High. Basic metabolic biochemistry, well-established.

Practical Application for Combat Athletes

Pre-training (60-90 minutes before):

Simple to moderate carbs: Banana, oatmeal, rice cakes, toast

Purpose: Top off glycogen, readily available energy

During training (if session >90 minutes):

30-60g carbs per hour: Sports drink, banana, energy chews

Purpose: Maintain blood glucose, delay glycogen depletion

Post-training (within 30-60 minutes):

40-80g simple carbs + 20-40g protein

Purpose: Rapid glycogen replenishment, muscle protein synthesis

Competition day (2-3 hours before first match):

Familiar carb sources only: White rice, banana, toast, oatmeal (not fiber-heavy foods that could cause GI distress)

Nitric Oxide Boosting Foods

Reminder: Nasal passages produce nitric oxide (NO), which enhances oxygen uptake in lungs and acts as a vasodilator.

Some foods boost systemic NO production:

Beets (beetroot juice):

  • High in dietary nitrates → converted to nitrite → converted to NO
  • Research shows 2-3 hours pre-exercise consumption improves endurance performance by 1-3%

Leafy greens:

  • Spinach, arugula, kale: Also high in nitrates

Citrus fruits:

  • Vitamin C supports NO production pathways

Garlic:

  • Supports vascular health and NO bioavailability

Timing and Dosing

Beet juice: 300-500ml (roughly 2 cups) 2-3 hours before training or competition

Regular consumption: Daily intake of nitrate-rich vegetables likely provides ongoing benefits (not just acute pre-competition use)

Confidence level: High for beet juice performance benefits in endurance exercise. Medium for combat sports specifically (limited research but mechanism translates).

Pre-Competition Nutrition Strategy

3 Days Before

Carb loading (moderate):

Increase carb intake slightly (2.5-3g per lb bodyweight) to maximize glycogen stores

Reduce fiber slightly (minimize GI issues)

Familiar foods only (not the time to experiment)

Day Before

Nutrition:

Moderate carbs + lean protein + vegetables

Nothing spicy, heavy, or unfamiliar

Avoid high-fat meals (slow digestion)

Hydration:

Maintain consistent water intake (don't over-hydrate or under-hydrate)

Avoid:

Alcohol (dehydrates, disrupts sleep, inflammatory)

Excessive salt (can cause bloating)

Morning Of (2-3 hours before first match)

Light breakfast:

Simple carbs + small amount of protein

Examples: Oatmeal with banana, toast with peanut butter, rice with eggs

Hydration:

12-16oz water with breakfast

Avoid:

Heavy meals, high-fat foods, dairy (if you're sensitive), caffeine (if not habitual)

Between Matches (60+ minutes apart)

Quick-digesting carbs: Banana, honey packet, rice cakes, sports drink

Small amounts—enough to maintain energy without GI discomfort

Foods That May Reduce Breathing Efficiency

Dairy (Individual Variability)

Some athletes report increased mucus production after dairy consumption.

Research is mixed—this seems highly individual.

Strategy: Test your tolerance. If you notice thicker mucus or respiratory discomfort after dairy, avoid 24-48 hours before competition.

High-Fat Meals

Slow gastric emptying, can cause bloating, may restrict diaphragm movement.

Avoid within 3-4 hours of training or competition.

Alcohol

  • Dehydrates (thickens mucus)
  • Disrupts sleep quality (impairs recovery)
  • Inflammatory (airways and systemic)
  • Impairs thermoregulation

Never within 48 hours of competition. Ideally limit during heavy training blocks.

Confidence level: High for alcohol's negative effects. Low-Medium for dairy (highly individual).

Supplements for Breathing Performance

Strong Evidence

Beetroot juice/powder: 300-500ml juice or equivalent powder 2-3 hours pre-competition (NO boost)

Omega-3 fish oil: 2-3g daily (EPA+DHA) for anti-inflammatory effects

Iron: IF deficient (test first, supplement only if needed)

Moderate Evidence

Quercetin: Some research shows improved airway function in athletes, 500-1000mg daily

Vitamin C: Supports NO production and immune function, 500-1000mg daily

Weak Evidence / Not Recommended

  • Most proprietary "respiratory support" supplements (marketing > science)
  • Breathing-specific formulas without disclosed ingredients or research backing

Whole foods first. Supplements are supplemental, not foundational.

The 24-Hour Competition Nutrition Timeline

Night before:

Familiar dinner, moderate carbs + protein, hydrate well, no alcohol

Morning of (6-7 AM for 10 AM start):

Light breakfast (oatmeal, banana, eggs), coffee if routine, 16oz water

2 hours before:

Small snack if hungry (banana, rice cakes), continue hydration

1 hour before:

Sips of water only

30 min before:

Minimal water if thirsty, apply CombatStrips with clear nasal passages

Between matches (60+ min gaps):

Quick carbs (banana, honey, sports drink), small amounts of water

Post-competition:

Full meal within 60 minutes (protein + carbs + vegetables), rehydrate aggressively

Sample Competition Day Nutrition

Breakfast (6 AM, first match 10 AM):

  • Bowl of oatmeal with sliced banana and honey
  • 2 scrambled eggs
  • 16oz water with electrolyte tablet

Mid-morning (8:30 AM):

  • Rice cakes with almond butter
  • 12oz water

Pre-match (9:30 AM):

  • Small sips of water
  • CombatStrips applied

Between matches (if 60+ min gap):

  • Banana
  • Honey packet
  • 8oz sports drink

Post-tournament:

  • Real meal: Chicken, rice, vegetables
  • 20+oz water

The Bottom Line

Nutrition affects every physiological system—including respiratory function.

Optimize what you eat:

  • Ensure adequate iron (oxygen transport)
  • Reduce systemic inflammation (airway function)
  • Stay hydrated (mucus viscosity and overall performance)
  • Time carbohydrates appropriately (oxygen-efficient fuel source)
  • Consider nitrate-rich foods (NO production boost)

Combined with proper training, recovery, and breathing optimization tools (like CombatStrips), nutrition becomes another percentage-point advantage that compounds over the course of a competition day.

Fuel the system correctly. Maximize the airflow. Execute the technique.

Next read: "Recovery Optimization for Combat Athletes" to understand how nutrition integrates with sleep and recovery protocols.