Seasonal changes can kill you, literally. It seems researchers in Sweden have found that when we "spring forward" to daylight saving time in the spring there are 6% more heart attacks. On the other hand when we "fall back" as we'll do on Saturday night there will be 5% fewer heart attacks the following day.
The best guess on this phenomenon is that since we're chronically sleep deprived today, average sleep duration has fallen from 9.0 to 7.5 hours in the last century, the sudden change can be fatal to a few vulnerable folks. The simple solution? Don't make sudden changes to your daily schedule, gradually adjust your routine to maintain a safe amount of sleep.