Answered questions
Sleep
80 answered questions · 499 studies
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How much melatonin should you take to sleep better?
For most adults, 4 mg appears to have the greatest effect, but it should be taken 2 to 3 hours before bedtime; if you are…
Moderate evidence
Does the sleepy girl mocktail (magnesium with cherry juice) help you sleep?
Magnesium may make some difference for older people with sleep problems or for people with a deficiency, but for healthy…
Preliminary evidence
Does mouth taping help you sleep better?
For healthy sleepers there is too little evidence to recommend mouth taping, and if you have a blocked nose it is risky. If…
Preliminary evidence
Does years of insufficient sleep damage your brain?
Years of insufficient sleep damages the brain through multiple pathways at once, and some of that damage appears difficult or…
Yes · Moderate evidence
What does a daytime nap do to your health?
A short nap of less than 30 minutes appears safe and good for alertness. People who regularly nap for longer than half an hour…
Moderate evidence
Does apigenin help you sleep better?
There are only preliminary signals from observational and animal research; clinical evidence in humans is entirely absent. If…
Preliminary evidence
Does taking glycine help you sleep better?
Glycine shows tentatively positive signals, but the evidence is thin and the only direct human study comes from the…
Preliminary evidence
Does poor sleep really shorten your life?
Consistently sleeping too little is associated with a measurably higher risk of earlier death and serious illness; the…
Yes · Strong evidence
Is it better to take ashwagandha in the morning or in the evening?
More important than the timing: several regulators advise against ashwagandha. The Dutch RIVM warns against it (liver,…
Insufficient evidence
Is it better to take magnesium in the evening?
Evening intake sounds logical given magnesium's role in melatonin and sleep, but there is no research that directly compares…
Preliminary evidence
Does too little sleep weaken your immune system?
Yes, too little sleep demonstrably weakens your immune system and increases the risk of infections and chronic inflammatory…
Do I sleep worse if I am often alone or feel lonely?
Yes, loneliness is clearly associated with poorer sleep: you have more difficulty falling asleep, wake up more often during…
Does your gut microbiome affect how well you sleep?
Your gut microbiome and your sleep mutually influence each other, but how to practically steer that through probiotics or…
What does chronic sleep deprivation do to your fertility when you are trying to conceive?
Chronic sleep deprivation and frequent insomnia have been linked in several large studies to a lower chance of conception and…
Does a consistent morning routine with daylight help you fall asleep more easily in the evening?
A consistent morning routine with daylight helps sharpen your biological clock, allowing you to fall asleep earlier and more…
Yes · Moderate evidence
Why am I wide awake in the evening when I feel tired during the day?
Your biological clock and your chronotype determine when your body wants to be awake. When that clock does not align with your…
Can chronically poor sleep cause me to have a stroke at a younger age?
Chronically poor or insufficient sleep is associated with an increased risk of cardiovascular disease, including stroke. If…
Yes · Strong evidence
Does your sleeping position affect how rested you feel when you wake up?
Sleeping position influences your sleep indirectly, through pain and breathing: sleeping on your stomach increases back…
Preliminary evidence
Can cognitive behavioural therapy help me sleep better long-term without pills?
CBT-I demonstrably produces lasting sleep improvement, even after the sessions end, something that does not apply to sleep…
Yes · Strong evidence
Does pain make me sleep worse, and what can you do about it?
Pain worsens your sleep, and poor sleep in turn increases the risk of pain. Approaches such as relaxation exercises, cognitive…
Yes · Moderate evidence
Does a blue-light filter on my phone really affect my sleep?
A blue-light filter on your phone probably has little effect on your sleep. If you really want to improve your sleep through…
No · Moderate evidence
What does chronic sleep deprivation do to your inflammation in the long run?
Chronic sleep deprivation demonstrably raises inflammatory markers in your blood and is linked to diseases such as…
What is sleep debt and can you really pay it back?
Sleep debt is real and has measurable effects on your cognitive function and metabolism, but full recovery takes more than a…
Yes · Moderate evidence
Does melatonin as a supplement really work for better sleep in older age?
Melatonin can modestly improve sleep in older adults, but the evidence is preliminary and little is known about long-term use.…
Preliminary evidence
Does CBD oil help you sleep better?
There is currently too little good research to say that CBD oil genuinely helps with sleep problems; if you suffer from them,…
Preliminary evidence
Are there foods you should avoid eating before going to bed?
Alcohol, caffeine and fatty meals close to bedtime disrupt your sleep. You sleep better by avoiding all three in the evening…
Yes · Moderate evidence
Can too little sleep make you more susceptible to infections?
Too little sleep demonstrably makes your immune system more vulnerable, including to infections and vaccinations. Make sure…
Yes · Moderate evidence
Is it true that older people get less deep sleep, and what does that mean?
Older people demonstrably get less deep sleep, and this is associated with higher risks of dementia and lower growth hormone…
Yes · Strong evidence
Does walking outside during the day help me sleep better at night?
A daily walk of around half an hour outside helps improve your sleep, as shown by a randomised study. The surroundings matter…
Yes · Moderate evidence
Do I sleep worse when I am stressed, and does that create a vicious cycle?
Stress worsens your sleep, and poor sleep in turn makes you more stressed and anxious. Improving sleep is therefore one of the…
Yes · Moderate evidence
Is there a link between sleep deprivation and bone loss?
There is serious evidence to suggest that sleep deprivation and poor sleep quality go hand in hand with bone loss, especially…
Does the time you eat affect how well you sleep?
When you eat influences your biological clock and probably also how well you sleep. The strongest practical takeaway is: try…
Can sleep deprivation raise your blood pressure?
Chronically sleeping too little is associated with a clearly elevated risk of high blood pressure. If your blood pressure is…
Yes · Moderate evidence
Why do you sleep worse as you get older, and do hormones play a role in that?
Sleeping worse with age is well documented and has multiple causes, including brain changes and, in women, the menopause.…
Yes · Moderate evidence
Does a sleep study in a clinic make sense, and when should you have one?
A clinic-based sleep study has its place, but not for ordinary sleep problems. It is only useful when your doctor suspects an…
Yes · Moderate evidence
Does melatonin support your immune system in later life?
Melatonin has clear effects on the immune system in animal and laboratory research, but whether supplements genuinely improve…
Preliminary evidence
Do you age faster if you sleep too little?
Sleep deprivation demonstrably disrupts the processes that keep the brain young, particularly the clearance of harmful…
Does valerian really help you fall asleep faster?
Valerian probably does not help you fall asleep faster. Multiple independent review studies and a recent controlled trial…
No · Moderate evidence
Does working nights increase my risk of cancer?
There are indications that prolonged night work slightly increases your cancer risk, but the evidence is limited and…
Moderate evidence
What does too little sleep do to your gut?
Too little sleep demonstrably disrupts the composition of your gut bacteria and lowers butyrate, a substance that helps…
Does your biological age advance differently at night than during the day?
Your body does not age faster at night than during the day, but the night is the primary recovery period and that recovery…
Why do I wake up tired even after sleeping for a long time?
Waking up tired despite sleeping for a long time is a normal phenomenon called sleep inertia, and the time of waking and…
Will my memory improve if I sleep more?
Getting enough sleep, and particularly the deep sleep phase, is an active part of how your brain retains new information. Too…
Yes · Moderate evidence
What is the difference between REM sleep and deep sleep, and do I need both?
You need both sleep stages: deep sleep and REM sleep each do something different for your memory and brain, and getting a full…
Yes · Moderate evidence
Can poor sleep cause me to develop diabetes sooner?
Consistently sleeping too little or poorly demonstrably increases your risk of type 2 diabetes, so it is worthwhile taking…
Yes · Moderate evidence
Do weighted blankets really help you sleep better?
A weighted blanket can reduce anxiety and improve sleep quality, but the evidence is still limited and largely based on small…
Preliminary evidence
What does long-term sleep deprivation do to your heart?
Prolonged sleep deprivation raises your risk of high blood pressure, coronary artery disease and diabetes through multiple…
Is it true that sleep before midnight is better for you than sleep after midnight?
A regular sleep rhythm that begins before midnight is associated with better health outcomes, but the timing alone is not…
Does the sleep tracking feature on my smartwatch have any value?
Your smartwatch gives a useful indication of your sleep pattern, but accuracy varies considerably by device and it is not a…
Moderate evidence
Why do I dream so much, and is that good or bad?
Simply dreaming a lot is normal and need not be a cause for concern. However, persistent nightmares or dreams that you…
Moderate evidence
Can poor sleep permanently disrupt your hormones?
Sleep deprivation measurably disrupts multiple hormones, but whether those effects are truly permanent has not been well…
Can a bed that is too warm cause me to sleep worse?
A bed that is too warm disrupts your sleep; a slight drop in body temperature is actually necessary for falling asleep well.…
Yes · Moderate evidence
Does magnesium really help you sleep better and keep your mind sharp?
Magnesium may help with sleep problems, but the evidence is still too limited and inconsistent to make firm claims. If you…
Moderate evidence
Does sleep deprivation age your skin faster?
Sleep deprivation demonstrably worsens your hydration, elasticity, and wrinkles, after as little as one poor night. Aim for…
What does exercising right before bed do to my sleep?
Vigorous exercise within 4 hours of bedtime demonstrably worsens your sleep; schedule your workout earlier in the day and you…
Does poor sleep increase my risk of cancer?
There are cautious indications that sleep problems may increase cancer risk, but the evidence is still too thin for a firm…
Preliminary evidence
Does creatine affect your sleep?
Creatine may improve how your sleep feels, but objective measurements show no effect. Do not use it primarily as a sleep aid;…
Preliminary evidence
Chronic sleep deprivation: how harmful is it for weight and hormones?
Chronic sleep deprivation disrupts your hormones and metabolism after just a few nights. Structurally sleeping too little…
Does stopping coffee in the afternoon really help my night's sleep?
One cup of coffee in the afternoon probably does not harm your sleep. Three to four cups can already ruin your night, even if…
Yes · Moderate evidence
Is sleeping in on the weekend beneficial, or does it fail to make up for sleep deprivation?
Sleeping in on the weekend temporarily relieves fatigue but does not genuinely make up for sleep deprivation: cognition,…
No · Moderate evidence
How much does a consistent sleep schedule actually matter?
A consistent sleep schedule genuinely matters. Irregular sleep times are strongly associated with more depression, anxiety, a…
Does my sleep change as I get older, and is that normal?
Your sleep genuinely changes with age: feeling tired earlier, sleeping more lightly and for shorter periods, and waking more…
Yes · Strong evidence
Is it a problem that I often wake up during the night?
Waking up occasionally is normal, but if it happens frequently and affects you during the day, there may be an underlying…
Moderate evidence
Does the menopause disrupt my sleep, and what can help?
The menopause genuinely disrupts your sleep, primarily through hot flashes and hormonal changes. Cognitive behavioural therapy…
Yes · Moderate evidence
What does sleep deprivation do to your immune system?
Sleep deprivation demonstrably weakens the immune system: it increases the risk of infection, reduces the response to…
Is L-theanine good for stress and sleep?
In small studies, L-theanine shows cautious signs of reducing stress and improving sleep, but the evidence is too thin and too…
Preliminary evidence
Is loud snoring dangerous for my health?
Loud snoring is associated with serious health risks: arterial calcification, higher mortality after a heart attack and…
Yes · Moderate evidence
Does a cool, dark bedroom really help you sleep better?
A bedroom temperature of 20 to 25 degrees combined with good ventilation demonstrably improves your sleep. This effect is…
Yes · Moderate evidence
Are sleeping pills harmful in the long term?
Long-term use of classic sleeping pills increases the risk of dependence, cognitive decline, and impaired driving ability.…
Yes · Moderate evidence
What does alcohol do to my sleep quality, and is there anything I can do about it?
Alcohol demonstrably harms your sleep quality, particularly in the second half of the night. Drinking less shortly before…
Yes · Strong evidence
How much sleep do I really need?
For most adults, 7 hours of sleep is the safe minimum, with 7 to 8 hours representing the best-supported optimum. Both too…
Does poor sleep cause dementia sooner?
Poor sleep probably increases your risk of dementia, but ordinary insomnia does not make dementia inevitable. One exception:…
Yes · Moderate evidence
What can I do to sleep better?
Regular exercise is the most solid route to better sleep. Supplements sometimes help, but results are mixed. If you have pain,…
Strong evidence
How bad is screen light in the evening for my sleep?
Evening screen light disrupts your sleep through a biologically demonstrated mechanism, but how large the effect is in…
Is a daytime power nap healthy or not?
A power nap of less than 30 minutes taken early in the afternoon provides a modest but measurable boost to alertness and…
Moderate evidence
How harmful is irregular sleep or shift work, and what can you do about it?
Shift work and night work increase the risk of cardiovascular disease, diabetes, sleep problems and mental health complaints.…
Yes · Moderate evidence
Does deep sleep flush waste products from your brain?
Yes, your brain cleanses itself largely during sleep, and deep sleep appears to play the most important role in this.…
How dangerous is sleep apnoea?
Moderate to severe sleep apnoea substantially increases your risk of cardiovascular disease, diabetes and depression.…
Is it safe to take melatonin every night?
For healthy adults, melatonin is safe with short-term use, but as a sleep aid for chronic insomnia it works considerably less…
Moderate evidence
Does magnesium help with poor sleep and muscle cramps, and which form should you take?
Magnesium may modestly speed up falling asleep in older adults with insomnia, but the evidence is small-scale and of limited…
Preliminary evidence