Transition from winter to summer and vice versa: consequences for the body of different age groups

Introduction: the challenge of chronobiology and adaptation

Quick changes in climate and time zones (jet lag) along with extreme seasonal changes represent a powerful stress for all regulatory systems of the body. This is not just "acclimatization," but a comprehensive restructuring of circadian rhythms, thermoregulation, autonomic tone, and immune response. The consequences of such a transition differ fundamentally for children, adults, and the elderly due to age-specific physiological characteristics and adaptive reserve.

Physiological basis of stress: more than just a change in temperature

The body faces a triple blow:

Disorientation of circadian rhythms. Disruption of "internal clocks" located in the suprachiasmatic nucleus of the hypothalamus. The production of melatonin (sleep hormone), cortisol (stress and alertness hormone), and digestive enzymes is disrupted. The body continues to live in "winter" mode when it's "summer" outside, and vice versa.

Extreme thermoregulatory shock. Emergency reprogramming of the heat exchange system is required: from working in conditions of cold stress with maximum heat retention to a cooling mode through sweating and expansion of peripheral vessels, which creates a load on the cardiovascular system.

Immunological provocation. A sudden change in the environment (new allergens, pathogens, temperature) temporarily reduces the effectiveness of the immune response, increasing the risk of respiratory and intestinal infections ("traveler's diarrhea").

Age groups: differentiated analysis of risks

1. Children (especially preschool and elementary school age)

The child's body has high plasticity, but its regulatory systems are still immature.

Consequences: Manifestations are pronounced and rapid: sleep disorders (child confuses day and night), moodiness, disturbances in appetite and digestion, possible fever due to stress. The risk of heat stroke is especially dangerous for babies during the transition "to summer" due to their imperfect thermoregulatory system and faster dehydration.

Critical fact: Studies show that the change in more than 2-3 time zones causes significantly more pronounced and prolonged disruptions in circadian rhythms in children under 3 years old than in adults. Their internal "clocks" synchronize more slowly.

Example: A child who flew from -20°C to +30°C may show weakness and refusal to eat on the first day — this is not just fatigue, but disorientation of the hypothalamus, which controls sleep, appetite, and thermoregulation.

2. Adults (25-50 years)

This group has the highest adaptive reserve, but the consequences depend heavily on the initial state of health and lifestyle.

Consequences: Classic symptoms of jet lag: insomnia or drowsiness, decreased cognitive functions (attention, memory), irritability, disturbances in gastrointestinal tract function. The transition "to winter" often exacerbates chronic inflammatory diseases (sinusitis, cystitis), while the transition "to summer" may trigger hypertensive crises in people with unstable blood pressure due to sudden vessel dilation and dehydration.

Critical fact: Scientific data indicate that adaptation during westward travel (extension of the day) is easier than during eastward travel (shortening of the day). However, the change of season complicates this scheme: a flight eastward "from summer to winter" is a double blow.

Example: A sportsman or a business person who has made such a flight may see a significant decrease in endurance, accuracy, and reaction speed for 3-5 days, which is confirmed by objective tests. This is due to a disruption in cortisol production and a violation of neuromuscular coordination.

3. Elderly people (65+ years)

The most vulnerable group due to the age-related decrease in functional reserves and the presence of chronic diseases.

Consequences: The risks are not just uncomfortable, but threatening to health. High probability:

Decompensation of cardiovascular diseases (hypertensive crisis, angina attack, arrhythmia) due to the load on vessels and changes in blood rheological properties.

Exacerbation of chronic cerebrovascular insufficiency with increased dizziness, ringing in the ears, risk of transient ischemic attacks.

Severe sleep and cognitive function disturbances that may take weeks to recover.

Expressed exacerbation of arthrosis and osteochondrosis when traveling to a cold and humid climate.

Critical fact: Research in the field of chronogeriatrics shows that the elderly have reduced endogenous melatonin production and less sensitive receptors. Therefore, the natural adjustment of circadian rhythms after travel is fundamentally disrupted in them and often requires pharmacological correction.

Example: An elderly person with early signs of atherosclerosis who has traveled from a cold winter to a tropical summer is at risk of experiencing a sudden spasm or, conversely, pathological dilation of cerebral vessels due to dehydration and pressure fluctuations, which may trigger a stroke.

General recommendations and strategies for mitigating consequences

Preparation (2-3 days before departure): Gradually shift the time of going to bed and meals towards the new time zone. Start an adaptogen course (prescribed by a doctor), for example, melatonin in small doses.

During the flight: Hydration is the cornerstone. Refrain from alcohol and caffeine. Use compression stockings to prevent venous stasis. Light exercise every 1.5-2 hours.

Upon arrival:

For everyone: Immediate synchronization with local time (if you arrive in the morning, do not sleep but go out into the light, if in the evening — help yourself with melatonin).

For children: A gentle regimen, plenty of fluids, light food. Do not plan active entertainment in the first 2-3 days.

For the elderly: Mandatory blood pressure and pulse control. Delayed start of any activity (postpone excursions for 3-4 days). Consultation with a treating doctor about possible therapy adjustments (e.g., temporary increase in the dose of antihypertensive drugs).

Conclusion

Traveling through several seasons is a serious physiological test, the scale of which depends directly on age. For a young body, it is often just temporary discomfort, but for the elderly, it is a real threat to health, comparable to a heavy stress load. Conscious planning of such a trip, taking into account age-related risks, sufficient time for adaptation, and, if necessary, consultation with a geriatrician (for the elderly) or a pediatrician (for children) — the only way to turn a sharp change from winter to summer into a potentially dangerous event into a manageable adventure.

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