Let's say normally, I go to sleep at 00:00 and wake up at 08:00. I know that 3 days from now, I will have to work in another city for just that day and wake up at 05:00 to account for the travel time.

How should I plan my activities and rest, so that I will not feel sleepless the night before, or feel tired when I wake up at 05:00?

  • Should I exercise in the afternoon, so my body feels tired and I can go to sleep early?
  • Should I eat more or eat less?
  • Should I gradually adjust my sleeping time starting from 3 days before, then adjust it back? (3 days before + 3 days after = my sleeping is irregular for 7 days)

I am not interested in medicines like a sleeping pill, as I believe some can be harmful to health in the long term.

  • 3
    Melatonin (youth hormone, also a sleeping pill) is not harmful for health, as it's hormone which you already have in your body which balance your sleep.
    – kenorb
    Commented Apr 14, 2015 at 18:13
  • 4
    @kenorb Just because it's a hormone doesn't mean it's harmless. Hormones can have pretty serious effects, they should be carefully evaluated just like any other drug.
    – user10
    Commented Apr 14, 2015 at 18:52
  • 1
    @kenorb that's like saying there are no side effects to taking the contraceptive pill - when there clearly are. Your body's hormones are at that level for a reason.
    – Tim
    Commented Apr 14, 2015 at 19:29
  • 2
    I'm sure not all hormones are safe to take, however I was talking about melatonin specifically (it has very low toxicity in studies), it's safe in long-term, available freely over-the-counter, you can't overdose it (all people who tried to commit a suicide with melatonin, they failed:) and majority of older people are taking it every the day for many years to regulate their biological clock.
    – kenorb
    Commented Apr 14, 2015 at 20:34
  • What is the scientific background to state that one needs to sleep 8 hours? It has also been suggested that what is imporant for good rest is to respect deep sleep by cycles, each cycle being of aprox. hour and a half. This may not be an acurate nor standard idea, but it's worth discussing. Reference: sleepyti.me.
    – nilon
    Commented Oct 18, 2016 at 11:55

2 Answers 2


Although the other answer provided some general tips about sleep hygiene and noted that melatonin might be helpful, your question actually touches on an aspect of circadian biology that has been very well worked out, and a more specific answer is available.

The question boils down to: How can I advance my circadian phase by 3 hours?

This is a question relevant for Eastward travel. It also comes into play during the spring time change for those who live where DST is observed as well as in the shift from weekend/holiday to weekday sleep patterns for many.

Begin by thinking of your body’s circadian pattern on an X,Y graph1 where:

x= time
y= activity

Your goal (“phase advance”) is to shift this curve leftward by three hours along the x axis.

When attempting to manipulate circadian phase, the key is to understand your body’s Zeitgebers.Your body intrinsically has circadian oscillators that confer the cycle and determine the period; Zeitgebers are external agents that entrain this oscillation by maintaining or shifting it along the x axis. The most powerful Zeitgeber, hands down, is light.

Now the question is: what is the relationship between light and this curve? That turns out to be slightly complex in that the answer depends on the time in the circadian cycle during which the stimulus is applied. The relationship has been very well worked out in some very cool experimental protocols. Here it is:2

enter image description here

Your goal is to achieve y= +3 (which corresponds to Δ= -3 along the x axis on the first graph). You can see here that an optimal light stimulus perfectly timed is able to achieve almost a 3-hour shift in a single cycle. The optimal stimulus is going to be bright light in the blue frequency range, and the optimal timing is going to be about 2 hours before your habitual wake time. (About 45 min duration is probably just as good as a longer duration.)

Practically, a good tip is: for two days prior to leaving, set your alarm an hour early and expose yourself to bright light (either broad-spectrum sunlight or blue light from a lightbox) for 30-45 min immediately upon waking. Each day’s exposure can be expected to achieve a 1-1.5 hour phase advance, and this protocol can be remarkably effective for mitigating the jet lag on the following day when you need to get up 3 hours prior to your habitual wake time.

The other answer mentioned melatonin. Administered exogenously, this is indeed another Zeitgeber, although much less powerful than light. Melatonin also has a phase response curve that turns out to be basically 180º shifted relative to the light PRC. That is, if the optimal timing for light to phase advance is around 2 hours prior to the habitual wake time, the optimal timing for melatonin administration will be 12 hours prior to that. For most people that corresponds to 4-6 hours prior to their habitual bedtime.

Eating and exercise are both fairly weak Zeitgebers, and I wouldn’t worry about them too much. As usual in circadian biology, it’s all about light!3

1. Image from: http://www.aasmnet.org/Resources/PracticeReviews/cpr_Actigraphy.pdf
Ancoli-Israel et al. The Role of Actigraphy in the Study of Sleep and Circadian Rhythms SLEEP 2003;26(3):342-92.
This sort of graph is obtained by plotting a cosine curve with a period of 24h using least-squares from data derived from wrist actigraphs that measure movement.

2. Image from: http://en.wikipedia.org/wiki/Phase_response_curve

3. All of this can be found in any introduction to circadian biology and/or sleep medicine. My own textbook is:
Kryger MH, Roth T, Dement WC. Principles and practice of sleep medicine. 5th ed. 2011: Saunders. St. Louis, MO.
The review of experimental protocols from Dr. Czeisler’s lab is also excellent and is freely available from PMC:
Duffy, JF. Czeisler, CA. Effect of Light on Human Circadian Physiology Sleep Med Clin. 2009 Jun; 4(2): 165–177.

N.B. ! Melatonin or light administered at the wrong time does the exact opposite. Although a three-hour phase shift is fairly easy to manage by predicting the phase of the PRC based on prior sleep habits, this starts to become more complicated in larger shifts. This is especially problematic in the case of Eastward travel >5h, when morning light at the destination ends up falling within the negative phase of the PRC and therefore delays the circadian curve. This is the wrong thing in this setting and is a common reason for protracted jet lag. Here, it is actually avoidance of morning light that is desired. This is complicated!


Body's biological clock

Biological clock human

Credits: A circadian rhythm at Wikipedia

There are two main hormones which plays important role in sleep.

  • Melatonin (also called a youth hormone) which is produced at night which plays a fundamental role in your body's biological clock (it governs the entire sleep and wake cycle).

  • Serotonin (“feel good” hormone) which affects wakefulness and our mood. Low levels (depression, fatigue).

When you are going sleep, your serotonin levels are converted into sleep-promoting melatonin by the body.

Usually body adjust to irregular sleep patterns (such as changing time zones) naturally, but it takes some time.

However if your body has a problem of adjusting to new pattern, you may considering regulating your biological clock.

Either by:

  • consider taking a melatonin (1mg or 3mg, usually sold freely over-the-counter) which in general it is considered to be effective and safe (as it's naturally occurring hormone) for short term use and long-term use of up to 12 months2012,
  • learn how to fall asleep naturally by reprogramming your brain and internal body clock to the new routine.

Sleep well

Sleep is important for our health and lack of sleep can put give you tiredness, fatigue and you're also increasing risk of serious medical conditions.

When planning your activities and rest, you should consider around 8 hours of good quality sleep a night to function properly (some of us need more or less time).

Take a nap

If you have a disturbed sleep patterns (such as irregular work times, night shifts) and you can't afford a good quality sleep, you can have a nap (a power nap) during the day when you get tired, it helps a lot. The benefits of napping could be best obtained by training the body and mind to awaken after a short nap. Naps of fewer than 30 minutes restore wakefulness and promotes performance and learning2007, 2008.

Relax your mind and body

Before going sleep, it's important to create an environment which can help you to sleep by relaxing your mind and body, and everyone have their own way, so here are some suggestions:

  • try to avoid TV, radio, using mobile or reading a book which can distract your mind,
  • turn of the light, draw the curtains, limit exposure to artificial light (it suppresses production of melatonin)wiki,
  • take a warm bath (it'll reach a temperature that's ideal for rest),
  • do some physical exercises:
    • relaxation exercises to relax your muscles (such as yoga),
    • vigorous physical activity (sex makes us sleepy as well),
  • try to listen to hypnotic music and sound effects to relax,
  • medication can help with sleeping problems,
  • write "to do" list for the next day to clear your mind of any distractions.

Source: How to get to sleep at NHS

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