The sun can make you feel tired for several key reasons:
- Your body uses extra energy to keep cool in the heat. When exposed to the sun, your hypothalamus triggers processes like sweating and increased blood flow to the skin to dissipate heat, which consumes energy and can cause fatigue.
- Dehydration from sweating under the sun reduces fluids and electrolytes, leading to tiredness as your heart works harder to pump thicker blood.
- UV exposure can trigger an immune response as your body repairs cellular damage, which may increase mental and physical fatigue.
- Physical activity outside in the sun often increases, contributing to tiredness.
- Your circadian rhythm naturally dips in alertness during early afternoon, coinciding with strong sunlight.
- Sunburn raises body temperature and further dehydrates, causing exhaustion.
- Eating patterns on sunny days and heat-induced metabolic changes also contribute to fatigue.
In summary, sun exposure leads to energy-intensive cooling processes, dehydration, immune activation, and sometimes increased exercise or sunburn , all of which combine to make you feel tired after spending time in the sun.
