Cold weather negatively impacts wellness and longevity by causing blood vessels to constrict, which raises blood pressure and increases risks of heart attack, stroke, and thrombosis. It elevates mortality rates through increased respiratory infections, arthritis pain, hypothermia, and mental health issues like SAD. Extreme cold also poses dangers to older adults through falls on ice and, ironically, can cause cardiovascular stress. 

Key Negative Impacts on Wellness and Longevity:

• Cardiovascular Strain: Cold causes vasoconstriction (narrowing blood vessels) to keep the core warm, raising blood pressure and thickening the blood, leading to higher heart attack/stroke risk.
• Respiratory and Immune Issues: Cold, dry air aggravates asthma, while colder temperatures and reduced sunlight can suppress the immune system and help viruses (like influenza) thrive.
• Physical Injury and Mobility: Icy conditions lead to falls and fractures, particularly in older adults.
• Mental Health Decline: Lower temperatures and reduced sunlight can cause or worsen Seasonal Affective Disorder (SAD) and depression.
• Immune System Suppression: Research shows that cold air in the nose can decrease the immune response, making individuals more susceptible to viruses.
• Reduced Physical Activity: Increased time indoors, often in poorly ventilated, crowded spaces, can lead to less activity and more frequent transmission of illness. 

While some studies suggest that cold exposure can improve metabolism or that mild, systemic reductions in body temperature might be linked to longer lifespan in animals, the acute risks of extreme, cold-weather exposure significantly increase mortality risk in humans, particularly regarding cardiovascular events.