Winter Blues

As of writing this, Kathmandu recorded the coldest day this season when the minimum temperature dipped to 2.4 degrees Celsius on Friday, January 9, 2026. For the past few months, the mercury has been on a steady decline nationally, troubling residents with cold-related woes. Hospitals have been seeing an influx of patients with winter ailments, especially colds, coughs, and cardiovascular and respiratory diseases and even psychological disorders. In winter, the human body tends to slow down as the mercury falls. The human body is complex but it is also equally delicate. It requires an optimal temperature for survival. 

When the temperature drops, the body undergoes thermoregulation, a process regulated by the hypothalamus, the brain’s internal thermostat, through which the body engages in a multi-system bid to maintain its core temperature at around 37 degrees Celsius. When faced with cold, the nervous system triggers peripheral vasoconstriction in which the blood vessels near the skin and the extremities, like hands, feet, ears and nose, tighten. The objective is to flow the warm blood away from the skin because heat escapes via radiation from the skin. 

Vasoconstriction keeps the warm blood concentrated around vital organs such as the lungs, heart and brain. In a way, it is a defence mechanism of the body to protect itself from the adverse effects of the chill. In case insulating blood flow doesn’t do the work, the body switches from heat conservation to heat production. One of its most visible responses is shivering as the brain signals the skeletal muscles to contract and relax rapidly in an effort to burn energy and gain heat as a byproduct. Metabolic spike also occurs to boost the metabolic rate through the release of hormones such as adrenaline. 

The entire human body responds to the cold that creates a ripple effect throughout the major organs. The heart pumps harder to push blood through the narrowed blood vessels. Due to the dry winter air, the linings of the lungs get inflamed, leading to coughing and a burning sensation, more so in people with asthma. In case of extreme cold, such as cold waves, fatalities occur as seen in the Terai region of Nepal. 

When it comes to brain and psychological health, this season, people are more vulnerable to Seasonal Affective Disorder (SAD), which is also referred to as “winter depression.” It follows a seasonal pattern, beginning in late autumn and peaking in the darkest and coldest months of winter. SAD occurs due to a lack of adequate sunlight and is worse in regions where sunlight is scant. Sunlight helps the production of serotonin, a “happy” chemical in the brain. Less sun means a drop in serotonin, triggering feelings of lethargy and sadness. 

Meanwhile, a decline in sunlight resets the human biological clock (circadian rhythm), leading to disruption in the daily routine. Likewise, the cold season can dysregulate the balance of melatonin, affecting sleep patterns and even mood. Common symptoms of SAD include low energy, craving of carbohydrate (leading to weight gain), oversleeping, mood disorders and generally feeling melancholy. Given such effects of the cold in the human body, it is necessary to take care with adequate health measures such as proper diet, exercise, regular checkups and adequate sunlight. Let’s take this season to recharge and reset.