Poor sleep has been associated with obesity. As I sleep poorly I decided to look into this effect further. I found this review paper which describes how the circadian system, sleep and hormones interact.
Some interesting points:
1) Leptin (the hormone that decreases hunger) increases during sleep. This explains why we don't wake up feeling hungry after a fast day.
2) Disrupted circadian pattern (such as occurs in shift work) leads to an array of disorders (e.g., sleep disorders, impaired glucose regulation and obesity) and decreased life expectancy.
3) Light levels are important in setting the 'body clock'. So low light in the evening primes the body for sleep, bright light in the morning promotes wakefulness. Even low light levels can disrupt sleep.
4) Other things can set the body clock: exercise, feeding and temperature:
Eating or exercising in the hours of darkness can disrupt sleep patterns;
5) Poor sleep can disrupt thyroid hormone levels.
6) Other hormones showing a circadian rhythm include growth hormone, insulin, prolactin, cortisol.
From this we can conclude that getting a good night's sleep may help us to maximise the benefits of fasting by helping to improve our metabolisms.
Unfortunately, the authors do not suggest how we could use this information to good effect, but luckily Mark's Daily Apple does!
Some interesting points:
1) Leptin (the hormone that decreases hunger) increases during sleep. This explains why we don't wake up feeling hungry after a fast day.
2) Disrupted circadian pattern (such as occurs in shift work) leads to an array of disorders (e.g., sleep disorders, impaired glucose regulation and obesity) and decreased life expectancy.
3) Light levels are important in setting the 'body clock'. So low light in the evening primes the body for sleep, bright light in the morning promotes wakefulness. Even low light levels can disrupt sleep.
4) Other things can set the body clock: exercise, feeding and temperature:
Eating or exercising in the hours of darkness can disrupt sleep patterns;
5) Poor sleep can disrupt thyroid hormone levels.
6) Other hormones showing a circadian rhythm include growth hormone, insulin, prolactin, cortisol.
Given that the sleep and hormonal systems are tightly integrated, it is conceivable that disruptions of their synchrony may have adverse health consequences.
From this we can conclude that getting a good night's sleep may help us to maximise the benefits of fasting by helping to improve our metabolisms.
Unfortunately, the authors do not suggest how we could use this information to good effect, but luckily Mark's Daily Apple does!
Intense exercise right before bed may suppress melatonin and delay the phase cycle. If you find yourself restless and too alert after your late night workouts, try earlier workouts.
Conversely, if duty beckons and you need to be alert and awake one night, an extensive exercise session enjoyed right before normal bedtime should suppress melatonin and prevent sleepiness.
Eating also appears to suppress melatonin secretion, so if you’re having trouble sleeping consider eating earlier in the evening.
You’ll just have to find what works for you.
