The Complete Guide to Athlete Nutrition and Immunity: From Season Strategies to Table Practice

Opening: The Athlete Who Caught a Cold a Week Before the Championship

I’ve been coaching athletes for about 15 years, spanning cycling, road running, and triathlon, and I’ve also worked with plenty of regular office workers who simply want to get in better shape. Over the years, the situation that has left the deepest impression on me—and the one I find most heartbreaking—isn’t someone blowing up during a race. It’s this: training going perfectly, form peaking at its highest point, and then catching a cold a week before race day.

I remember one long-distance cyclist—let’s call him A-Kai. That season, his power improved dramatically; his threshold power jumped from around 260 watts to nearly 300 watts. His weight loss was also successful, dropping from 72 kg to 67 kg, and his resting heart rate fell from 58 bpm to 48 bpm. Every metric told me: he was ready. Then, eight days before the championship race, he sent me a message: “Coach, my throat feels weird. I think I’m getting a cold.”

At that moment, I knew very well that the problem usually didn’t originate “that week”—it was the accumulation of several weeks prior: training volume piled too high, sleep compressed by work, pre-race nerves killing his appetite, and cutting carbs too aggressively to control weight. Immunity is like a reservoir. If you’re constantly leaking water without refilling it, one day the water level hits rock bottom, and when a virus happens to knock on the door, it gets in.

In this article, I want to walk through “athlete nutrition and immunity” from the scientific foundation, to season strategies, all the way to practical table-side application—especially in the Taiwanese context: the hot, humid climate, eating out every day, and a healthcare system that’s convenient but also easily overused. I’ll give you tables and action checklists you can follow directly. Let me state the conclusion first: There is no magic supplement for immune support. What truly works is sufficient energy, sufficient carbohydrates, sufficient sleep, and keeping stress within a range your body can repair.

This article is educational content and cannot replace individual diagnosis and treatment advice from a physician, physical therapist, or dietitian. All values below are general ranges; please consult a professional for personalized guidance.

Concepts and Scientific Foundation: How Exercise Actually Affects Immunity

Moderate Exercise Protects; Excessive Exercise Is the Risk

Let’s bust a myth first: exercise does not make you weaker. In fact, extensive epidemiological observation shows that people who engage in regular moderate-intensity exercise tend to have lower rates of upper respiratory tract infections (URTI—what we commonly call colds, sore throats, stuffy noses) than those who are sedentary. Exercise is overall good for the immune system.

The real problem arises when there’s an imbalance between “volume” and “recovery.” When training becomes prolonged, high-intensity endurance work—for example, high-intensity riding or running exceeding 90 minutes—the body enters a window of reduced immune surveillance.

The “Open Window” Theory

There’s a classic concept in exercise immunology called the “open window theory.” It means that after a prolonged, high-intensity endurance effort, for roughly 1 to 9 hours afterward, the body’s immune defenses temporarily decline, forming an “open window” that makes it easier for opportunistic viruses and bacteria to sneak in.

During this period, studies have observed multiple immune markers being suppressed for several hours, including natural killer (NK) cell activity, partial T-cell and B-cell function, upper respiratory neutrophil function, and salivary immunoglobulin A (IgA) concentration. IgA plays a crucial role as the first line of mucosal defense. When it drops, the chance of viruses entering through the nasal and throat mucosa increases significantly.

Epidemiological data reflects this too: endurance athletes show elevated URTI risk during heavy training periods and in the one to two weeks following a marathon or similar event. Some observations indicate that people with very high weekly running volume (e.g., over 96 km) get sick at roughly twice the rate of those with low weekly volume (under 32 km). (Source listed in the references at the end.)

I want to specifically note: the academic community still debates whether acute immune suppression “directly” causes more infections, and some researchers believe exercise has been portrayed too scarily in the past. So please understand the “open window” as a risk window that needs managing, not a verdict that you will definitely get sick. If you manage it well, the window opens smaller and closes faster.

Why Nutrition Is So Critical Here

Immune cells are among the most metabolically active cells in the body. They need energy and raw materials to fight. When you’re in a state of chronic insufficient energy intake (what’s known as Low Energy Availability), the body prioritizes allocating limited resources to core functions for “survival,” while downgrading “non-urgent” systems like immunity, reproduction, and bone repair. This is why endurance athletes who diet too aggressively for weight loss are especially prone to recurrent colds, slow-healing wounds, and lingering fatigue.

Another key factor is blood sugar and stress hormones during exercise. When prolonged exercise causes blood sugar to drop, the body secretes stress hormones (such as cortisol) to cope, and these stress hormones themselves have immunosuppressive effects. This brings us to the most evidence-based nutritional strategy—consuming carbohydrates during exercise.

The Full Picture of Immune-Supporting Nutrition

I like to think of immune-supporting nutrition as a pyramid. From bottom to top, the lower levels are more important and offer better cost-effectiveness. Many people get it backwards—they neglect the foundation and rush to buy supplements at the very top.

Level	Content	Importance	Common Mistakes
Foundation (Most Important)	Sufficient total calories, sufficient carbs, sufficient sleep, stress management	★★★★★	Drastically cutting calories and carbs for weight loss
Second Level	Adequate high-quality protein, distributed across three meals	★★★★☆	All protein packed into dinner, almost none at breakfast
Third Level	Colorful fruits and vegetables, whole grains, fermented foods (gut microbiota)	★★★★☆	Severely insufficient fruit and vegetable intake
Fourth Level	Targeted correction of micronutrient gaps (e.g., vitamin D)	★★★☆☆	Supplementing blindly without testing, excessive dosages
Apex (Icing on the Cake)	Situation-specific supplements	★★☆☆☆	Treating the apex as the foundation, buying “miracle drugs” excessively

Foundation One: Energy and Carbs—Don’t Sacrifice Immunity for Lightness

This is the point I most want to hammer home. Many cycling and running enthusiasts are obsessed with “lightening up,” treating body weight as their only KPI, and thus staying in a chronic energy deficit. In the short term, you’ll get lighter and your climbing numbers will look great. But a few months later, you start getting recurrent minor colds, poor sleep, menstrual irregularities (in women), decreased libido, and low mood—these are all your body crying out for help.

One of the most evidence-supported nutritional strategies for immunity is consuming carbohydrates during prolonged exercise. Research consistently shows that taking in carbs during high-intensity endurance exercise lasting over 90 minutes can attenuate exercise-induced immune suppression, with the mechanism being maintaining blood glucose and blunting the stress hormone response. (Source listed at the end.)

General practical recommendations:

Exercise Duration	Hourly Carb Intake (General Range)	Format Suggestions
< 60 minutes	Usually no extra needed (rinsing the mouth is enough)	Plain water
60–150 minutes	Approximately 30–60 grams	Sports drinks, energy gels, bananas
> 150 minutes	Approximately 60–90 grams (requires training gut tolerance)	Mixed polysaccharides, alternating solid and liquid

Taiwan’s summers are hot and humid. Long-distance rides or runs easily cause heavy sweating and suppressed appetite. In this situation, “drinking your carbs” is more practical than chewing solid food. I often tell my athletes to treat sports drinks as “part of cold prevention,” not just for hydration and electrolytes.

Foundation Two: Sleep and Stress—Good Nutrition Can’t Save You from Chronic Sleep Deprivation

No matter how good your diet is, it can’t make up for chronic sleep deprivation. Sleep is the immune system’s maintenance window. Adults are generally advised to get 7–9 hours, and those with high training volumes often need more. Among the athletes I’ve coached, whenever someone drops below 6 hours of sleep while simultaneously increasing training load, a cold is almost inevitable. Taiwanese office-worker athletes need special attention here: daytime work stress, evening training, then staying up late to catch up on work—this is the most damaging combination for immunity.

Layer 2: Protein — Distribution Matters More Than Total

Protein provides the raw materials for immunoglobulins, cell repair, and enzymes. For athletes, the general daily protein range is about 1.4–2.0 grams per kilogram of body weight. For a 65 kg runner, that’s roughly 90–130 grams per day.

The key isn’t just the “total” — it’s also the “distribution.” Many people have toast with milk tea for breakfast, a bento box for lunch, and cram all their protein into dinner. That approach isn’t very efficient for muscle synthesis and repair. I’d recommend spreading protein evenly across three to four meals, with roughly 20–40 grams per meal.

Common Taiwanese Foods	Approximate Protein Content
One egg	About 6–7 grams
One 450 ml serving of unsweetened soy milk	About 12–15 grams
One palm-sized chicken breast	About 25–30 grams
One container of unsweetened yogurt	About 8–10 grams
One serving of braised tofu and seaweed	About 10–15 grams

Layer 3: Vegetables, Fruits, Whole Grains, and Gut Microbiota

Colorful vegetables and fruits provide vitamin C, polyphenols, and phytochemicals. These aren’t miracle cures, but they serve as the background support for a properly functioning immune system. Rather than obsessing over a single “superfood,” aim for diversity of colors on your plate — a bit of dark green, orange-red, and purple-black.

The gut is home to the body’s largest immune organ. Fermented foods (unsweetened yogurt, kimchi, miso, natto) along with adequate dietary fiber help maintain the gut microbiota, which is closely linked to immune regulation. These aren’t hard to find in Taiwan — a container of unsweetened yogurt at breakfast or an extra small dish of kimchi on the table are both simple, doable practices.

Layer 4: Micronutrient Gaps — Test First, Then Supplement

Here I want to address something Taiwanese people often overlook — vitamin D. Many assume that because Taiwan gets plenty of sunshine, deficiency can’t be an issue. But in reality, due to sun protection, indoor work, and daily routines, vitamin D insufficiency among athletes is actually not uncommon.

Research shows that endurance athletes with low vitamin D status may experience more days of upper respiratory tract infections and greater symptom severity during winter training compared to those with adequate vitamin D status. Vitamin D also plays a role in innate immune regulation and is an important factor for mucosal and systemic immunity. (Source at the end of the article.)

But please note: this does not mean you should go buy high-dose supplements at the pharmacy and start popping them. The correct approach is to first get a blood test for 25(OH)D, and only if deficient should you supplement at a dosage recommended by a professional. In Taiwan, seeing a family medicine or sports medicine clinic for this test — whether covered by NHI or self-paid — is very convenient. Vitamin D is fat-soluble, and long-term excessive intake carries toxicity risks. This is a classic example of “test first, then supplement; give a range, don’t fake precision.”

Other nutrients worth watching include iron (especially for women, vegetarians, and high-volume runners, who are prone to deficiency — iron deficiency affects oxygen transport and immunity) and zinc. Same principle: only get tested if you have symptoms or belong to a high-risk group; don’t supplement indiscriminately.

At-a-Glance Table: Key Nutrients Related to Immunity

To give you an overall map, I’ve compiled the nutrients most relevant to immunity and commonly deficient in athletes into the table below. Again, these are general ranges and role descriptions, not a prescription for self-medication. Especially for fat-soluble vitamins and minerals, over-supplementation carries risks — individual dosages must be evaluated by a physician or dietitian.

Nutrient	Role in Immunity (General Description)	High-Risk Groups for Deficiency	Common Taiwanese Food Sources	Notes
Carbohydrates	Maintains blood glucose, lowers exercise stress hormones	Those dieting for weight loss, those trying keto	Rice, noodles, sweet potatoes, bananas, sports drinks	Must replenish during long sessions
Protein	Raw material for immunoglobulins and cell repair	Those who skip breakfast, unplanned extreme vegetarians	Eggs, soy milk, chicken breast, yogurt	Spread across three to four meals
Vitamin D	Participates in innate immune regulation, mucosal defense	Excessive sun protection, indoor work, winter training	Moderate sun exposure, salmon, egg yolks	Fat-soluble, test before supplementing
Iron	Oxygen transport and immune cell function	Women, vegetarians, high-volume runners	Red meat, dark green vegetables, legumes	Harmful in excess, requires testing
Zinc	Involved in immune cell proliferation	Extreme diets, poor gastrointestinal absorption	Oysters, lean meat, nuts	High doses long-term interfere with copper absorption
Polyphenols / Phytochemicals	Antioxidant, supports overall recovery	Those with insufficient fruit and vegetable intake	Colorful vegetables and fruits, tea, dark berries	Diversity beats any single “superfood”

The right way to read this table is: first make sure the foundation (carbohydrates, protein) is in place, then check whether you’re in a high-risk group for a specific gap, and only then consider whether to test or supplement. Don’t do it in reverse — don’t see “vitamin D supports immunity” and rush to the pharmacy to stock up.

Season Strategy: Different Phases, Different Approaches

Immune nutrition isn’t a one-size-fits-all approach — it needs to shift with your training cycle. I’ll break a typical season into four phases.

Season Phase	Training Characteristics	Nutrition and Immunity Focus
Base Phase	High volume, moderate intensity	Calories and carbs should keep pace with training load; establish fruit/vegetable and sleep habits; this is a good time to schedule blood tests for vitamin D/iron
Build Phase	Intensity rises, high open-window risk	Always fuel long sessions with carbs; within 60 minutes post-training, take carbs plus protein; strictly prioritize sleep
Taper Phase	Training volume decreases	Slightly reduce calories but don’t slash carbs; maintain protein; avoid trying new foods or supplements at this stage
Post-Race Recovery	Immunity most vulnerable	One to two weeks post-race is a high-risk window for colds; replenish energy and sleep, reduce crowd exposure and fatigue

Build Phase: Treat “the Post-Training Meal” as an Immune Investment

The build phase carries the highest open-window risk. The 1 to 2 hours after a hard, long session is when your body is most vulnerable. I require my athletes to replenish carbs and protein as soon as possible after training (generally recommended within 30–60 minutes). An easy ratio to remember is roughly 3:1 to 4:1 carbs to protein.

A practical Taiwanese version can be very simple: a glass of unsweetened soy milk with a banana, an onigiri with a tea egg, or a light bowl of chicken rice. No need to spend big money on imported supplements — the point is to get the raw materials in while the window is open so your body can repair, rather than staying hungry and waiting two or three hours to eat.

Taper Phase: This Is When “Spur-of-the-Moment” Is Most Dangerous

The phrase I most often remind athletes during the taper is: “Race week is not experiment week.” Don’t suddenly switch to brand-new fueling products, suddenly go keto, or suddenly chug a bunch of supplements you’ve never tried. Stomach issues, allergies, or diarrhea can ruin everything you’ve worked so hard to prepare. All fueling strategies should have been practiced during training.

Post-Race Recovery: The Most Overlooked High-Risk Window

Many people think once the race is over, they’re in the clear. In reality, the one to two weeks after the race are the peak period for catching a cold. A full-effort marathon or long-distance event temporarily suppresses immunity, and combined with post-race celebration, late nights, dietary indulgence, and constant travel, it’s very easy to get sick. My approach: for the first few days after the race, deliberately get plenty of sleep, replenish energy and carbs, avoid crowded enclosed spaces, and wash hands frequently. Discipline during this period matters just as much as before the race.

One-Day Immune-Friendly Meal Plan (Taiwan Eating-Out Version)

Many trainees think that “supporting immunity” means cooking at home and buying a bunch of imported ingredients. In reality, Taiwan’s eating-out environment makes it entirely doable if you know how to choose. Below is a sample plan for training days, based primarily on eating out (general range, not precisely calculated; consult a dietitian for individual calorie needs).

Time	Sample Choices	Immune Focus
Breakfast	Unsweetened soy milk + egg pancake (less sauce) + one piece of fruit	Start with protein and carbs; don’t skip breakfast
Lunch	Chicken leg bento (ask for extra vegetables, normal portion of rice)	Enough protein, enough carbs, add vegetables
During Training	Sports drink or energy gel (for long sessions)	Maintain blood sugar, keep stress hormones low
Post-Training	Rice ball + tea egg or unsweetened soy milk + banana	Catch the recovery window, carbs plus protein
Dinner	Buffet: three vegetable dishes, one meat, one bowl of rice + miso soup	Color variety, fermented foods, fiber
Late-Night Snack (if needed)	Unsweetened yogurt or a small bowl of sweet potato	Gut bacteria, avoid nighttime energy deficit

There is nothing expensive or exotic in this meal plan—everything can be found at Taiwan’s breakfast shops, convenience stores, and buffets. The threshold for immune-supporting nutrition is much lower than people think; the hard part is consistency.

Case Study: The Female Runner Who Got Sick More the More She Trained

I’d like to share another case because it’s very typical, especially among female endurance runners. Let’s call her Xiao-Jie, a dedicated half-marathon runner aiming to break two hours (finishing a half marathon in under two hours). She came to me feeling confused: “Coach, I’m training more and more diligently, so why do I keep getting sore throats every few days, and my period has become irregular too?”

I asked her to roughly write down her recent daily routine and diet. I could see the problem right away: in order to “run lighter,” she had cut her daily carbs very low. She often went out with just a black coffee for breakfast, had a salad for lunch, while her training volume kept increasing. She had indeed lost two or three kilograms, but the cost was chronic energy deficit.

For female athletes, long-term low energy availability doesn’t just affect immunity—it also impacts hormones, menstruation, and bone health. These things are all connected. I didn’t give her any supplements. Instead, I did three very “counterintuitive” things:

1. Bring back breakfast: No more just black coffee; switched to soy milk with sweet potato or a rice ball, so she had an energy foundation from the start of the day.
2. Start fueling during long sessions: For any training over 90 minutes, she had to bring a sports drink or energy gel.
3. Reset her goals: Remove “body weight” from the top priority and replace it with “training quality” and “how I feel.”

After about six to eight weeks, her recurring colds improved significantly, she had more energy in training, and her menstrual situation was also adjusting (I asked her to see a gynecologist and a family medicine doctor for individual assessment, rather than just taking my word as a coach). This case reinforced my conviction: many immune problems are rooted not in supplements, but in energy and carbs being cut too aggressively.

Common Mistakes and Corrections

Over the years, I’ve seen too many smart people fall into the same traps. Here are the most common ones and how I help correct them.

Mistake 1: Chronic Energy Deficit for Weight Reduction

This is the number one killer in the cycling and running community. Symptoms include recurring minor colds, fatigue, poor sleep, and irregular menstruation in women. Correction: Acknowledge the risk of low energy availability, demote body weight from being the sole KPI, and prioritize adequate calories and carbs. Weight loss should be gradual, not through aggressive fasting during the season.

Mistake 2: Treating Supplements as the Foundation

Many people don’t eat vegetables or fruit and don’t get enough sleep, yet spend big money on high-dose vitamin C, probiotics, and various imported miracle pills. Correction: Go back to the base of the pyramid. No supplement can repair the immune damage caused by chronic sleep deprivation and energy deficiency. Supplements are the tip of the pyramid, not the foundation.

Mistake 3: Supplementing Vitamin D/Iron Without Testing, or Completely Ignoring Them

Both extremes are wrong: one is completely ignoring them, the other is buying high doses and taking them recklessly. Correction: If you belong to a high-risk group (heavy training, vegetarian, female, little sun exposure), get tested. Supplement only if deficient, and follow professional advice. Fat-soluble vitamins especially should not be taken in arbitrary amounts.

Mistake 4: Training Hard While Sick

The “neck rule” is a commonly used general reference in practice: if symptoms are only above the neck (mild nasal congestion, scratchy throat), with no fever and no body aches, light activity is usually fine; but if you have fever, body aches, chest tightness, coughing from the chest, or diarrhea, you should rest completely and consider seeing a doctor. Correction: Pushing through high-intensity training while sick not only prolongs the illness but can also lead to more serious problems (such as the risk of viral myocarditis). In Taiwan, seeing a doctor is convenient—if you feel unwell, go see one. Don’t tough it out.

Mistake 5: Trying New Things on Race Week

As mentioned earlier, I’ll emphasize it again: no new fuel, new food, or new supplements should appear on race week.

Actionable Advice for Readers at Different Levels

For Beginners / General Exercisers

You don’t need to overthink this. Do these three things and you’ll be ahead of most people:

1. Have protein at every meal, and don’t skip breakfast.
2. Sleep at least 7 hours—this is more effective than any supplement.
3. Add more color to your plate, and find ways to eat two extra servings of vegetables and fruit daily.

At this stage, you don’t need to buy any supplements at all. Master the fundamentals, and your immune foundation will be solid.

For Intermediate Athletes / Hobbyists with a Regular Training Plan

You already have structured training, so now you can start doing “strategic” things:

1. Always fuel with carbs on long sessions (>90 minutes), treating it as part of your immune protection.
2. Consume carbs plus protein within 60 minutes post-training to catch the recovery window.
3. Consider getting blood tests for vitamin D and iron, supplement only if deficient, and follow professional dosage recommendations.
4. Adjust your eating across the season: increase intake during build phases, and don’t slash carbs during deload phases.

For Competitive Athletes / Coaches

You’re dealing with details and periodized management:

1. Incorporate immune risk into training planning, deliberately emphasizing sleep and energy replenishment during build phases and after races.
2. Monitor load and recovery markers (such as resting heart rate, subjective fatigue, sleep quality) to detect early warning signs of immune decline.
3. Establish collaboration with sports dietitians/physicians for individualized handling of micronutrients and special needs.
4. Build a standard pre-race protocol, rehearsing fueling, eating, and bedtime in advance—zero experiments on race week.

Immune Protection Checklist for High-Intensity Weeks

When you enter a high-volume week (such as a build-phase peak week or the final heavy stacking week before a race), I give trainees a simple daily checklist. Think of it like a pilot’s pre-flight checklist—not to make you paranoid, but to turn the things most easily overlooked and most damaging to immunity into habits.

Check Item	Pass Standard (General Reference)	What to Do If You Don’t Pass
Sleep	Slept at least 7 hours last night	Consider downgrading the day’s intensity session or switching to an easy session
Breakfast Energy	Has both carbs and protein, not leaving on an empty stomach	Grab something immediately; don’t start the day in a deficit
Long Session Fuel	Brought carbs for sessions over 90 minutes	Prepare a sports drink or energy gel before heading out
Post-Training Replenishment	Ate carbs plus protein within 60 minutes	Keep a rice ball or soy milk on hand
Vegetables & Fruit	At least three servings of different colored vegetables/fruit today	Add two extra vegetable dishes at the dinner buffet
Hydration	Urine is light yellow, no obvious thirst	Increase fluid intake, especially in hot and humid weather
Body Signals	No scratchy throat, unusual fatigue, or elevated resting heart rate	If warning signs appear, reduce volume, monitor, and see a doctor if necessary

The most valuable column on this chart is actually the last one—body signals. I often tell trainees that your body sends you early warnings: your throat starts feeling odd, your morning resting heart rate is 5 to 10 bpm higher than usual, or you feel inexplicably tired despite sleeping enough. These are signs that the “window” is opening. The smart move at that point is to proactively reduce volume and maximize recovery, rather than forcing through the plan. Being willing to hit the brakes at the right time is one of the biggest differences between elite athletes and everyone else.

Hydration and Immunity in Taiwan’s Humid Heat

Taiwan’s climate is a variable we cannot ignore when discussing immunity. With summer temperatures often reaching 32–33°C combined with high humidity, sweat loss during long rides or runs is staggering—losing one to two liters of fluid per hour is not an exaggeration. Dehydration itself is a physiological stressor that raises core body temperature, increases cardiovascular strain, and indirectly amplifies the body’s overall stress response, which is not friendly to the immune system.

In practice, I remind athletes: hydrate before long sessions, rather than waiting until you feel thirsty; during exercise, take small, regular sips of water with electrolytes—in humid heat, don’t drink only plain water to avoid hyponatremia; and after exercise, replenish not just fluids but also the sodium you’ve lost. The simplest at-home indicator of adequate hydration is urine color—ideally a pale yellow. If it’s dark and scant, you haven’t been drinking enough.

A side note for friends with chronic conditions: if you have hypertension, heart disease, or kidney-related issues, hydration, electrolyte intake, and exercise intensity in hot, humid environments require more cautious, individualized assessment. Be sure to discuss appropriate strategies with your physician first, and don’t simply follow general advice.

Common Questions FAQ

These are the questions I get most often from my athletes. I’ve compiled them here for you.

Q: Can taking lots of vitamin C prevent colds?

A: For the general population, the evidence for high-dose vitamin C preventing colds is not strong. Rather than relying on a single high-dose supplement, it’s more robust to eat a sufficient variety of colorful fruits and vegetables, obtaining natural vitamin C and other phytochemicals from food.

Q: Should I take probiotics or not?

A: The gut microbiome is indeed linked to immunity, but commercial probiotic products vary widely, and effects differ from person to person. I usually recommend starting with naturally fermented foods (unsweetened yogurt, kimchi, miso, natto) and adequate dietary fiber—this is the least controversial and most cost-effective approach. If you want to add a probiotic supplement, consult a professional.

Q: I often get sick after big races. Is my constitution just weak?

A: Not necessarily—it’s more likely a combination of the “open window” plus disrupted post-race routines. After an all-out race, immunity naturally dips temporarily. If you then stay up late celebrating, eat erratically, and rush around, your odds of getting sick naturally rise. Treat the one to two weeks after a race as a serious recovery period, and the situation often improves.

Q: Can I exercise when I have a cold?

A: Refer to the “neck rule” mentioned earlier as a general guideline: if symptoms are confined to above the neck, with no fever and no body aches, light activity is usually fine—just monitor how you feel. Once you have a fever, body aches, chest tightness, a cough that reaches your chest, or diarrhea, you should rest completely and consider seeing a doctor. With Taiwan’s convenient healthcare access, if you’re unsure, go see a physician rather than toughing it out on your own.

Q: What should vegetarian athletes pay special attention to?

A: A well-planned vegetarian diet can fully support training and immunity, but pay particular attention to total protein and its distribution, as well as iron, zinc, vitamin B12, and vitamin D—nutrients that are more prone to deficiency. I recommend working with a sports dietitian for an individualized nutrition plan.

Practical Tips for the Taiwan Context

Let me add a few very local reminders. Taiwan’s summers are hot and humid, and long exercise sessions cause heavy sweating, so hydration and carbohydrate intake need to be more aggressive—dehydration itself adds to physical stress. Eating out in Taiwan tends to be high in sodium, high in fat, and low in vegetables and fruit—that’s our inherent disadvantage—so “actively ordering extra vegetables” and “actively choosing unsweetened drinks” need to become reflex actions. National health insurance makes seeing a doctor very easy, which is a good thing—if you feel unwell, go see one; don’t self-diagnose with internet information. But don’t use that convenience as an excuse to push through—when you have a cold, you still need to rest.

Back to A-Kai from the opening. That year, because of a throat warning sign eight days before the race, we made an immediate decision: cut the final week’s intensity to a minimum, sleep until naturally waking, top up energy and carbohydrates, and stay away from crowds. He didn’t develop a full-blown cold, and he made it to the starting line on schedule. It wasn’t the best race of his career, but he finished—and he was healthy. From then on, immune nutrition and recovery became a mandatory topic in every season’s planning.

Training gives you a ceiling, but recovery and immunity determine whether you can actually reach that ceiling. Take care of the foundation, manage the window, and leave the rest to your effort on race day.

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A final reminder: this article is educational content and does not replace individualized diagnosis or treatment advice from physicians, physical therapists, or dietitians. If you have diabetes, hypertension, heart disease, or other chronic conditions, any dietary, supplement, or training adjustments must be discussed with your healthcare team for individualized assessment. Do not make your own judgments or rely on internet information.

References

• Nieman DC. Risk of upper respiratory tract infection in athletes: an epidemiologic and immunologic perspective. PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC1320353/
• Upper Respiratory Tract Infections in Sport and the Immune System Response. A Review. MDPI Biology. https://www.mdpi.com/2079-7737/10/5/362
• Influence of vitamin D status on respiratory infection incidence and immune function during winter training in endurance sport athletes. PubMed. https://pubmed.ncbi.nlm.nih.gov/23977722/
• Vitamin D3 Supplementation Reduces the Symptoms of Upper Respiratory Tract Infection during Winter Training in Vitamin D-Insufficient Athletes: A Randomized Controlled Trial. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164435/
• Exercise-Induced Immunodepression in Endurance Athletes and Nutritional Intervention with Carbohydrate, Protein and Fat. PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475230/

Related Reading

• Immune Nutrition for Athletes: Dietary Strategies to Prevent Colds and Keep Your Season from Crashing at the First Cough
• Getting Sick the More You Train? A Full Breakdown of Exercise and Immune Dysregulation: Overtraining-Induced Immunosuppression, Recovery, and Nutritional Strategies
• Probiotics and Athlete Gut Health: Immunity, Evidence, and a Selection Guide (Coach’s Practical Edition)
• Zinc and Immune Supplementation for Athletes: A Complete Guide to Timing, Cold Prevention, and Safe Upper Limits