With the holidays approaching, many are already anticipating the unpleasant symptoms that come with crossing time zones and losing sleep. Jet lag is real and it can ruin a portion of your vacation.
Now, researchers are saying that chronic jet lag may be more damaging than previously thought. Along with short term problems like fatigue, jet lag can cause memory and learning problems that linger long after resuming a normal wake-sleep schedule.
The researchers conducted their study on hamsters. The hamsters were subjected to six-hour shifts in time. They did this to the hamsters twice a week for four weeks. The researchers liken this disruption in sleep-wake cycles to that experienced on a flight from New York to Paris. Measurements were taken during the last two weeks of jet lag and a month later in a follow up session. Specifically, the researchers wanted to know how the hamsters would perform during memory and learning tasks.
The research team found that jet lag caused the hamsters to perform badly when it came to learning simple tasks—exercises that well-rested hamsters had no trouble completing. These results were no surprise to the researchers. However, what they weren’t expecting was the persistence of these cognitive difficulties for up to a month after resuming a normal day-night schedule.
It seems the chronic jet lag triggered changes in certain areas of the brain. The area most affected was the hippocampus, an area of the brain responsible for memory processing.
According to the researchers, the jet lagged hamsters were significantly impaired when it came to the production of new neurons in the hippocampus. By the end of the study, the control group had twice as many new neurons as the jet lagged group. Anyone who has memory problems also likely suffers from a drop in the production of new neurons. A healthy hippocampus will create new neurons at a steady and constant rate. The researchers also noted that it was likely that there were also fewer neurons developing into mature neurons and new neurons dying before reaching maturity.
The researchers say the results should sound an alarm for those who travel regularly, work nights, or have disrupted sleep patterns due to aging. When your circadian rhythm is thrown off balance, you’ll likely experience long term impacts that affect your ability to learn and remember.
To avoid some of these adverse changes, the next time your sleep is disrupted by crossing time zones, make sure you allow one recovery day for each one-hour time shift zone. You can also try taking melatonin supplements.
Sometimes people end up with a disrupted sleep pattern due to so-called “social jet lag.” Social jet lag is a phenomenon where you regularly disrupt your normal circadian rhythm by staying up too late or getting up too early to participate in some activity such as keeping a partner company or going to work. For those suffering from social jet lag, make sure you adjust your sleep cycle to include eight hours of sleep in a dark room that’s quiet.
Sources:
Sanders, R., “Jet lagged and forgetful? It’s no coincidence,” UC Berkley News Center web site; Nov. 24, 2013; http://newscenter.berkeley.edu/2010/11/24/jetlag, last accessed Nov. 28, 2013.
Srinivasan, V., et al., “Jet lag: therapeutic use of melatonin and possible application of melatonin analogs,” Travel Med Infect Dis. January-March 2008; 6(1-2): 17-28.