Why do I always get sick on holiday?

Since it’s becoming such a commonly seen thing around this time of year, the holiday or weekend cold is being referred to as “leisure sickness,” according to The Guardian. A leading theory suggests during the span of days or weeks spent working before vacation, your immune system shifts into a high gear. However, once you’re done and well on your way to your holiday destination, it lets down its guard, allowing that ever-famous sore throat or stuffy nose to make its way back into your life.