Dr Hari Kishan Boorugu, physician at Yashoda Hospitals, Hyderabad, said heat risks don't reduce after sunset. "Nighttime heatwaves are considered more dangerous...because...body doesn't get enough time to recover from daytime heat," he said. Sweating continues, but it's less noticeable. So, people fail to replace lost fluids. Warm nights push body towards dehydration and electrolyte imbalance.