Infectious Gastroenteritis and Top Athletes

What is Infectious Gastroenteritis? — The “Sudden Stomach Pandemic”

Infectious gastroenteritis is an acute inflammation of the stomach and intestines caused by viral or bacterial pathogens. These organisms are usually transmitted via the fecal-oral route—through contaminated hands, food, or surfaces. Once inside the gastrointestinal tract, they disrupt the gut’s normal function, leading to symptoms such as vomiting, watery diarrhea, abdominal cramps, and low-grade fever.

In Japan, norovirus is one of the most prevalent causes of winter outbreaks. Due to its highly contagious nature, it often spreads rapidly in crowded environments such as schools, offices, sports facilities, and medical institutions.

Main Causative Pathogens

Pathogen	Incubation Period	Main Symptoms
Norovirus	12–48 hours	Sudden vomiting, watery diarrhea, cramps
Rotavirus	1–3 days	Profuse diarrhea, vomiting, moderate fever
Adenovirus	5–7 days	Diarrhea, fever, sore throat
Salmonella	6–72 hours	Fever, abdominal pain, bloody stools

Why Does Infectious Gastroenteritis Cause Rapid Weight Loss?

Dr. Yoshimasa Goto, internal medicine specialist, explains that infectious gastroenteritis can cause abrupt weight loss due to several compounding factors:

1. Massive fluid and electrolyte loss: Repeated episodes of vomiting and diarrhea lead to significant loss of body water and essential minerals (sodium, potassium, chloride), causing dehydration and sudden weight drop.

2. Reduced caloric intake: Patients often experience anorexia, nausea, or are advised to fast, further decreasing calorie and nutrient availability.

3. Impaired digestion and absorption: Inflammation of the gut lining hinders normal absorption of nutrients, exacerbating malnutrition and catabolism.

For the average person, this may cause mild fatigue and weakness. But for high-performance athletes, the impact is magnified.

Preventive Advice from an Infectious Disease Specialist

To minimize risk and severity:

• Wash hands frequently and thoroughly with soap and running water for at least 30 seconds.

• Clean up vomit or feces using disposable gloves and masks; disinfect surfaces with sodium hypochlorite (bleach).

• Reheat food until steaming hot; ensure internal temperature exceeds 85°C for at least one minute.

• Isolate infected individuals and avoid sharing toilets, towels, or utensils.

Note: Alcohol-based hand sanitizers are ineffective against norovirus. Physical handwashing and chlorine-based disinfectants are essential.

Gut Health: A Crucial Factor for Athletes and Businesspeople Worldwide

This time, the issue gained attention because Mookie Betts, a teammate of Shohei Ohtani on the MLB’s Los Angeles Dodgers, reportedly lost 8 kilograms due to infectious gastroenteritis. Ohtani himself has mentioned in interviews that “maintaining health while continuing to play sports is not easy,” highlighting how vital health management is for top athletes.

Even minor illnesses like gastroenteritis can significantly impact performance. Maintaining gut health is essential to immunity, hydration, energy absorption, and ultimately, physical and mental readiness.

Services We Provide:

At Goryokai Clinic Shirokanetakanawa, we offer:

• Prompt diagnosis and treatment of infectious gastroenteritis (viral and bacterial)

• IV fluid therapy for dehydration correction

• Medical consultations for travelers, including vaccination advice

• Long-term care for chronic diarrhea, post-infectious IBS, or gut microbiota recovery

🏃‍♂️ Why Top Athletes Lose Weight Rapidly from Infectious Gastroenteritis

Elite athletes maintain finely tuned physiques akin to high-performance race cars—built for speed, not endurance. While this allows for maximum output, it also leaves little physiological margin for error during illness.

Here’s a closer look at why gastroenteritis may hit athletes particularly hard:

① Extremely Low Body Fat = Minimal Energy Reserve

With body fat levels typically between 5–10%, top athletes have reduced capacity to store energy. Infections cause metabolic acceleration and appetite loss, depleting available energy rapidly.

② High Muscle Mass Is Susceptible to Breakdown

Muscle acts as a metabolic buffer. However, in the absence of food and with energy demands heightened by fever and immune activation, the body resorts to breaking down muscle (catabolism) for fuel, leading to swift mass loss.

③ Compromised Immune Resilience

Lean bodies often have less adipose tissue to support hormonal and immune responses. Dehydration and malnutrition further suppress immune defenses, potentially prolonging illness or increasing severity.

④ Dehydration and Electrolyte Imbalance Hurt Performance

A mere 2% loss in body weight due to dehydration can reduce endurance, concentration, and coordination. Rehydration alone doesn’t ensure full recovery—tissue repair and neuromuscular function must also normalize.

Message from Dr. Goto

“Athletes sculpt their bodies for optimal performance, but that optimization also means reduced tolerance for disruptions. Infectious gastroenteritis, though common, can be a serious setback if not addressed early. Prevention, hydration, and tailored recovery are key.”

 

Contact Us Anytime

📍 Goryokai Clinic Shirokanetakanawa (Medical Corporation Goryokai)
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 Contact & Appointments: 03-6432-5353

🗾 Read this article in Japanese here:
https://goryokai-shirokanetakanawa.jp/blog/%e3%80%90%e3%83%95%e3%82%b8%e3%83%86%e3%83%ac%e3%83%93-%e3%82%81%e3%81%96%e3%81%be%e3%81%978%e5%87%ba%e6%bc%94%e3%80%91%e5%a4%a7%e8%b0%b7%e7%bf%94%e5%b9%b3%e9%81%b8%e6%89%8b%e3%81%ae%e3%83%81%e3%83%bc/