Like food, exercise is also a very weak circadian synchronizer, so it doesn’t help reset your circadian clock. The time at which you exercise may also lead you to see light at the wrong time and shift your clock in the wrong direction, making your jet lag worse. Exercise has to be timed as part of the overall light-dark exposure plan.

Many claims have been made about diets or fasting being able to reset the clock. These claims are based on studies of nocturnal (night-active) rodents which cannot easily be translated to (day-active) humans. Food does not reset the circadian clock in the brain and there is currently no accepted method for using food — or fasting — for resetting circadian rhythms.

The evidence for this is found in studies of totally blind people, who Dr. Lockley has studied extensively. Totally blind people have no light information reaching the brain and therefore cannot synchronize the circadian rhythms to the 24-hour day. This results in a clinical disorder called non-24-hour sleep-wake disorder. They still get this disorder even though they eat their meals on a regular 24-hour pattern; if food could reset their circadian clock, they would not develop non-24-hour sleep-wake disorder, yet they do, showing that food is not an effective method to reset the clock.  

While advice on what and when to eat may be helpful in reducing the metabolic consequences of jet lag, caused by eating at the wrong biological time, it will not alleviate the underlying cause.

Sleep equals dark as far as the circadian clock is concerned – when you close your eyes to sleep, you block light information going from the eyes to the brain - so if you sleep at a time when you should be seeing light, you will shift your circadian clock in the wrong direction and make jet lag worse. Advice focused only on sleep, without resetting the circadian clock, assumes that insomnia and sleepiness are the only symptoms of jet lag, which is not the case. Sleep (and therefore dark) timing should be scheduled as part of the overall light-dark exposure plan designed to reset the circadian clock, and end jet lag, as quickly as possible.

Jet lag is a disruption of our internal 24-hour circadian clock, which regulates almost every biological system in our bodies. As a consequence, jet lag is disrupting our entire biology — from our sleep-wake cycle, mood and performance patterns to our metabolic, immune, and reproductive systems.

Jet lag causes a wide range of symptoms and significant financial costs:

• Insomnia
• Poor concentration
• Reduced performance
• Compromised safety
• Less enjoyment
• Needing to leave earlier than wanted to gradually acclimatize to the new time zone
• Long recovery time when back home
• Weakened immune system
• Long-term health implications

Any jet lag ‘solution’ that does not have light and light avoidance as the central planks of the advice will not help you adapt to new time zones faster. Some advice may aim at improving sleep or reducing sleepiness, but this is not addressing the circadian rhythm disruption which is the underlying cause of jet lag — a little like treating a fever without addressing the underlying infection. This may seem to help in the short-term but is not the most efficient or effective solution and does not address other consequences of jet lag such as digestive disorders and immune problems.

Given that appropriately timed light exposure and light avoidance are the only proven way to alleviate jet lag, many of the common ‘tips’ are either ineffective or may even make your jet lag worse. For example, knocking yourself out with sleeping pills, or getting on the new time zone as quickly as possible, or following the light-dark pattern on the plane, do not work.

Timeshifter uniquely combines the only elements shown to reset the circadian clock (light-dark exposure and melatonin supplements), and alleviate the symptoms (light, melatonin, caffeine, naps), and not surprisingly, the sum of their effects is greater than the individual parts. There are many scientific studies attesting to the benefits of our approach, and our algorithm has been used for many years by NASA, F1 drivers and elite athletes, and more recently by astronauts and mission controllers at Axiom Space.

Our Chief Scientist is Steven W. Lockley, Ph.D. Dr. Lockley is a Neuroscientist at Brigham and Women’s Hospital, an Associate Professor of Medicine in the Division of Sleep Medicine at Harvard Medical School. With almost 30 years of research experience, he is considered an international authority on how to reset the circadian clock.