Top medical news headlines for the week 39

Why the start of your run feels so difficult

Many runners describe the first 10 to 15 minutes of a run as the hardest of all. Breathing can feel labored, the legs can feel heavy and a pace that would normally seem manageable may suddenly feel surprisingly difficult.

Kratom cases climb sharply across the US

Addiction treatment centers across the United States are seeing more patients who have become dependent on kratom and a stronger compound made from it, known as 7-OH.