Travelling sports medicine. Guidelines for illness and jet-lag

Skærmbillede 2016-03-01 kl. 13.38.32Jet lag – Introduction


“Jet lag” occurs as a result of travel across several time zones

Definition of “Jet lag”: A transient clinical syndrome (collection of symptoms) that occurs in response to a disruption of normal biological rhythms and classically results in non-specific symptoms • Develops in most individuals when they travel across three or more time zones

Characterized by two phases:

  • De-synchronization phase: development of circadian dysrhythmia
    • Disruption (de-synchronization) of the normal biological clock (circadian rhythms) by external cues (light and dark cycles) – crossing several time zones rapidly (few hours e.g. intercontinental flights) affects circadian rhythms – external cues of the previous time zone have to be adjusted to the new time zone – Development of “jet lag”
  • Resynchronization phase: adaptation to the new time zone
    • Resynchronization – Occurs over a few days (factors to be discussed) – Re-setting of circadian rhythms – Correlates with the resolution of the symptoms of jet lag. More time zones crossed, the longer it takes to resynchronize the circadian rhythms – Rule of thumb – it takes approximately 1 day per time zone crossed to resynchronize

Basic physiology of circadian rhythms

  • An inherent “body clock” is situated at the base of the Hypothalamus (in the suprachiasmatic nuclei)
  • The body clock regulates the body’s normal rhythm – 24 hours long (“circadian rhythm”)
  • Rhythm – implies that the body clock has to be continually “adjusted” to be in synchrony with the day’s 24-hour solar day
  • Synchrony is achieved by “zeitgebers” (time givers).
  • There is an inherent periodicity of 24 to 26 hours, and exists in a number of physiological systems in the body
  • Function – internal time indicators for the body
  • Circadian rhythms are important in the normal regulation of physical and psychological parameters such as body temperature, blood cortisol levels, and alertness (sleep and wake cycle)

Symptoms of Jet lag

• General malaise • Headaches • Insomnia • Fatigue • Lethargy • Apathy • Dizziness • Non-specific gastrointestinal distress • Reduced appetite • Poor mental and psychological task performance • Reduced athletic performance

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Clinical guidelines

Clinical guidelines: Advice to reduce illness in the travelling athlete

Be aware of the higher risk periods for illness (? It is the destination not the travel) 2. Knowledge of expected illness and types 3. Travelling: • Know the destination (altitude, pollution, allergens, food) • Medical screening of athletes (respiratory illness, allergies, past history of illness, dermatological screening) • Vaccinate / chemoprophylaxis • Hand sanitizers • Avoid hand shaking • ? Probiotics 4. Planning of medical support – medical kit, nutrition, fluids 5. Establish contact with medical colleagues/services in destination countries 6. Educate athletes • Foods – e.g. bottled water, unpeeled fruits • Report symptoms early (isolation) • Personal hygiene (e.g. hand washing / sanitizers)

Coping with jet-lag: A Position Statement for the European College of Sport Science

Illness in Travelers Returned From Brazil: The GeoSentinel Experience and Implications for the 2014 FIFA World Cup and the 2016 Summer Olympics


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