When it comes to motives for getting a good night’s sleep we
don’t usually think about our body’s hormones. But sleep allows many of our
hormones to replenish so we have the optimal energy, immunity, appetite and
coping ability to face the day’s highs and lows.
The activities we do during the day – from having a fight
with a partner, using our iPhones at night, running in a race, to travelling
overseas – also affect our hormone levels and, in turn, our quality of sleep.
For both men and women, changes in our levels of sex
hormones can affect how well we sleep. These differences also change with age.
Understanding the connections between hormones and sleep may
help improve your own sleep and well-being.
What are hormones?
Our body’s hormones are like chemical messages in the
bloodstream which cause a change in a particular cell or organ and surrounding
tissues. The hormone adrenaline, for example, is produced by the adrenal glands
(on top of the kidneys) and helps prepare the body’s “fight or flight” response
during times of stress.
Hormones control many of the body’s processes, including
growth, development, reproduction, responding to stress, metabolism and energy
balance.
Hormones are linked with sleep in a number of ways.
Hormones affect sleep through our
stress levels
Some hormones, such as adrenaline, make us feel more alert
and prepared for action. This then makes it hard for us to go to sleep. To
prevent this effect, it’s best to do relaxing activities before bedtime, rather
than stressful work tasks or intense exercise.
When stress is long lasting, adrenocorticotrophic hormone
within the pituitary gland (attached to the base of the brain) triggers the
release of cortisone and cortisol from the adrenal glands.
Levels of adrenocorticotrophic hormone tend be higher in
people with insomnia than in good sleepers. This suggests that excessive
arousal and ongoing stressors contribute to the insomnia.
Elite athletes can have difficulty getting to sleep because
they tend to have high levels of cortisol throughout the day, including in the
evening.
Hormones released during sleep boost
our immune system and make us hungry
Sleep is a time when several of the body’s hormones are
released into the bloodstream. These include growth hormone, which is essential
for growth and tissue repair, including in adults.
Sleep helps to balance our appetite by maintaining optimal
levels of the hormones ghrelin and leptin. So, when we get less sleep than
normal we may feel an urge to eat more.
Sleep also controls levels of the hormones insulin and
cortisol so that we wake up hungry, prompting us to eat breakfast, and we are
prepared for facing daytime stress.
If we get less sleep than normal our levels of prolactin may
get out of balance and we can end up with a weakened immune system, difficulty
concentrating and carbohydrate cravings during the day.
Hormones stop us from having to get
up in the night to go to the bathroom
Changes in hormonal levels during sleep, including higher
levels of aldosterone and antidiuretic hormone, prevent us from needing to go
to the toilet. In children, while the hormonal system is still developing,
bedwetting may be partly influenced by low levels of antidiuretic hormone.
Hormones make us feel sleepy at night
Hormone levels also influence the timing of when we feel
sleepy and awake – our body clock or sleep-wake cycle. The hormone melatonin is
released with darkness and tells our body it’s time to sleep. This is why being
around too much bright light before bed can affect our sleep as it can stop the
release of melatonin. It’s also why it can be hard for night-time shift workers
to sleep during the day.
While artificial melatonin is available, taking the wrong
dosage and at the wrong time of day can make things worse, so it’s best used
with the guidance of a medical doctor.
Hormones give us a wake-up call in
the morning
Levels of the hormone cortisol dip at bedtime and increase
during the night, peaking just before waking. This acts like a wake-up signal,
turning on our appetite and energy.
When we travel long distances our body’s sleep-wake cycle
takes a while to adjust. So increased cortisol levels and hunger may occur at
inappropriate times of the day.
For women, changes in hormones affect
sleep
The relationship between hormones and the sleep-wake cycle
in women is further influenced by the menstrual cycle. Just before a woman’s
period, hormonal changes, including the sudden drop in levels of progesterone,
affect the body’s temperature control, which in turn can reduce the amount of
“REM” sleep. This is the stage of sleep when most of our dreams occur.
For women with severe premenstrual symptoms reduced levels
of melatonin before bedtime just before their menstrual period can cause poor
sleep, including night-time awakenings or daytime sleepiness.
Changes in hormone levels also contribute to sleeping
difficulties during pregnancy. Increased progesterone levels can cause daytime
sleepiness, particularly in the first trimester. High levels of oestrogen and
progesterone during pregnancy can also cause nasal swelling and lead to
snoring.
During menopause, low levels of oestrogen may contribute to
sleeping difficulties. Changes in hormone levels mean that body temperature is
less stable and there may be increases in adrenaline levels, both of which can
affect sleep.
The loss of oestrogen causes body fat to move more to the
stomach area, which increases the chances of women having snoring and sleep
apnoea.
For men, testosterone levels affect
sleep
For men, levels of testosterone are highest during sleep and
require at least three hours of sleep to reach this peak. Low levels of
testosterone in men, which can occur with sleep deprivation, ageing and
physical problems, have been associated with a reduction in sleep efficiency
and changes to the stages of sleep men experience.
Testosterone can be taken as a drug but abuse of it can lead
to other sleep problems.
Hormones influence our dreams
Finally, as we sleep, our hormones, including levels of
oxytocin and cortisol, may influence the content of our dreams.
By doing things to promote good sleep, such as reducing
stress, engaging in relaxing evening routines before bed, going to bed and
getting up at regular times, or seeking professional help for sleeping
difficulties, we can facilitate the replenishing activities of our hormones
that help us make the most of our day and optimise our well-being.
p/s: How great Allah created us, right? Subhanallah.
