Jet lag. Jumping a few time zones causes problems with sleep and even digestion. But new research means we could be a step closer to preventing this voyager's vexation. The study centers on the hormone vasopressin, thought to have a role in maintaining our internal clock. Researchers genetically engineered mice that do not respond to vasopressin. Both engineered and normal rodents lived in a set cycle of light and dark for 2 weeks. Then the researchers changed the light cycle by eight hours. And the vasopressin-insensitive mice recovered from their induced jet lag much more quickly than did their hormone sensitive peers. The work is in the journal Science. Jet lag may seem like a minor annoyance. But for those who travel frequently or work unusual hours, it's a chronic problem that can increase the risk of hypertension and obesity. You cannot simply knock out vasopressin signaling permanently—that would have negative effects on behavior and brain activity. But a drug that temporarily suppresses vasopressin to reduce jet lag may be a flier's dream.