Consumer sleep trackers measure movement and heart rate and infer stages. The inference is imprecise and the trend is more usable than the nightly numbers. Posting it because the silence on this was starting to look like agreement.
Sleep tracking data and its considerable limitations — setting out what I have, and where I think it stops being reliable.
A measurement question rather than a physiology one.
Consumer sleep trackers report stages. I understand those stages are inferred from movement and heart rate rather than measured, which makes the nightly breakdown considerably less solid than the total.
Which of the numbers these devices produce is worth looking at, and which should I stop reading?
This follows the opening post rather than contradicting it.
Appetite suppression and nighttime eating: if nighttime eating was a pattern, appetite suppression changes that pattern. Sleep can worsen if nighttime waking is habitual and now there is no appetite-based reason to wake.
Useful. I have added it to my own notes with the date on it.
A sleep diary with times rather than impressions is the only way to tell a real change from a remembered one, and it takes a minute a day.
It is worth checking rather than assuming, which costs nothing.
Obstructive sleep apnoea: pre-existing OSA can worsen with weight before it improves (apnoea-hypopnoea index goes up as soft tissue inflames before weight is lost). This is self-limited but uncomfortable during active weight loss.
I have left out the parts I could not verify.
Same experience here, different supplier, so it is at least not unique to one of them.
Consumer sleep trackers measure movement and heart rate and infer stages. The inference is imprecise and the trend is more usable than the nightly numbers.
Posting it because the silence on this was starting to look like agreement.
Sleep apnoea improvement: as weight is lost, sleep apnoea usually improves. The timeframe is weeks to months, not immediate. Improvement often is gradual rather than sudden.
It is one reading of the data and not the only reasonable one.
This follows post #8 rather than contradicting it.
When sleep problems need attention: if sleep does not improve as weight loss continues or if it worsens, discussing with a clinician is prudent. Sleep disorders are real and treatable.
The claim is narrower than it sounds, and deliberately so.
I read post #10 twice before replying, because I had assumed the opposite.
Caffeine and alcohol both affect sleep architecture and both change during a period of reduced intake without anybody deciding to change them.
Adding it because I spent an afternoon working it out and nobody should have to twice.
Understood. Thank you for being specific about the limits of it.
Sleep quality changes reported here have several plausible contributors, and separating drug effects from weight change, from schedule change, and from anxiety is genuinely difficult.
Coming back to post #15, because the follow-up matters more than the original answer.
Energy availability affects sleep in both directions, and a large deficit can produce either fragmentation or unusual sleepiness.
I would call that likely rather than established.
Thank you for taking the time. That was more work than a reply usually is.
Energy and sleep needs: rapid weight loss increases real metabolic stress. Sleep needs might increase even though appetite for food has decreased. Prioritising sleep is prudent during active weight loss.
If the premise is wrong, everything after it is decoration.
Eating patterns shift substantially and late intake affects sleep independently of anything pharmacological.
The practical version of sleep is three sentences long. The rigorous version is three pages and reaches the same conclusion with the conditions attached.
Worth separating two things that post #20 runs together.
Stimulants and sleep: if supplementing with caffeine or other stimulants for energy during weight loss, timing and dose matter for sleep. Evening stimulant use interferes with sleep.
Not the answer, but possibly the question that gets there.
The published data on sleep outcomes in this class is thinner than the volume of discussion, which is worth saying plainly.
Consistency of timing does more for most people's sleep than any intervention discussed in this subcategory.
Following this. I have the same question and no better information than the first post.
Post #27 answers the question as asked. The question underneath it is different.
Sleep quality versus quantity: some people report changes to sleep duration; others report changes to sleep quality without duration change. Both can matter for recovery and daytime function.
Adding this to the thread rather than to the wiki, because I am not confident enough for the wiki.
Reading rather than contributing, but this is the most useful thread I have found on it.
Gastrointestinal effects overnight: nausea or reflux or constipation at night can disrupt sleep. Dosing timing (morning versus evening) might help if nighttime GI symptoms are the problem.
Worth one more sentence than it usually gets.