A reader asks:

 I used my light box at 8 a.m. during daylight savings time. Now that we’re back on standard time, should I use it at 7 a.m., since that’s when the light would still be the same in relation to the biological clock?


When shifting from daylight savings to standard time, we need to give the biological clock an opportunity to shift also. Think about it as a jet-lag adjustment — you want to resynchronize to the new time zone. Rather than resisting the change — in your example, by using the lights at 7 a.m. rather than 8 a.m. — you should accelerate the readjustment. One approach is to skip light therapy on Sunday morning after the time change, allowing your internal clock to drift later (ideally, by an hour). On Monday morning, you resume at 8 a.m. standard time. Most people achieve this adjustment effortlessly, but some experience distinct jet-lag-type symptoms that can last up to several days.