Page Contents:
1) Napping Ability Survey Questions with Result Percentages
2) Respondent Anecdotes / Additional Notes
3) Interpretation of Napping Survey Data
4) Additional Thoughts on Napping Ability
5) Personal Note from the Admin
From 2 April 2025 to 16 April 2025, we ran an informal survey on the napping ability of Sighted Non-24 patients.
Compared to data gathered from napping surveys of the general population, there seems to be a lower incidence of napping ability among those with Sighted Non-24. In other words, Sighted Non-24 patients may not be able to nap as easily as the general population, whether free-running or not.
A total of 60 Sighted Non-24 patients were surveyed.
Demographic information, such as gender and age, was not collected.
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Question #1: “Do you have Sighted Non-24?”
56% … Yes, Self Diagnosed
42% … Yes, Formally Diagnosed
2% … Maybe/Other
“No” responses were not recorded.
Why was this question asked?
This survey was only open to those with Sighted Non-24. Self-diagnoses were accepted due to the diagnostic criteria simply being sighted with rotating sleep as detailed in a sleep log. In other words, official diagnoses are sometimes difficult to come by due to the rarity of this disorder, and since it is fairly easy for patients to self-diagnose based on collected sleep log data, their responses are accepted and appreciated.
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Question #2: “Which option best describes you?”
49% … I free-run and am unable to nap.
34% … I free-run and am able to nap.
8% … I do not free-run and am not entrained to a 24-hour day.
5% … Other.
3% … I am effectively treated for Non-24 (entrained to 24-hour day).
Why was this question asked? This question was asked to clarify the effect of napping on the current Non-24 status. A perfect example of why we asked: One other response detailed, “I currently free-run and no longer need naps” compared to when they could not fully free-run. Another said, “I struggle to nap because it takes me 1 – 2 hours to fall asleep.” Please note: terms such as entrainment and free-running were defined on the survey page.
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Question #3: “What is your napping frequency?”
29% … I cannot nap at all.
14% … I cannot nap except for once every few years.
14% … A few times a week.
12% … No options apply (explain).
10% … A few times per month.
7% … A few times per year.
5% … Once per month.
5% … A couple times quarterly.
5% … Nap daily.
Question #3 Details: For the purpose of this question, respondents were asked to consider a nap to be 2 hours or fewer and not part of a normal full sleep period.
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Question #4: “Why do you nap?”
41% … Recent sleep deprivation
37% … N/A – I cannot nap
32% … General fatigue
29% … Illness
7% … Other* (explain)
2% … Enjoyment or relaxation
*The four “other” responses:
1) “Does not nap.”
2) “Sedatives like allergy medications.”
3) “I think I wake up ‘too early’ and need to take naps.”
4) “I nap for 2 hours everyday 4 hours after waking for the day, regular, seems to be part of my sleep rhythm.”
Question #4 Details: The purpose of this question was to clarify the data from the previous question, which worked out well, especially since so many respondents had too much variance to answer the last question. Please note: For this question only, respondents could select all of the options that applied to them.
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Question #5: An Any-Use Text Box for Patient Anecdotes
All anecdotes are assumed to be a different patient/respondent and are each from a different survey submission. This was the only question which did not require an answer to progress through the survey. The content of these answers was not changed, but they have ever-so-slightly been edited for punctuation, typos, and formatting. The purpose of obtaining and sharing these responses is to better clarify the relationship Sighted Non-24 patients have with napping and to help others better understand, empathize, and/or relate to these responses.
Reminder: Each quotation is a different respondent.
“I can only nap if I’ve been awake for 24+ hours or am sick, I.E. flu.”
“I sometimes skip a night’s sleep by staying up 24+ hours and although I would love to nap in that time, I always stop myself because I know I will sleep for at least 8 hours and ruin my cycle even more.”
“I wish I could nap.”
“Every now and then I feel like I could potentially nap. The problem is that if I let myself, even if I only sleep for a half an hour I’ll be awake several hours past my normal sleep time, won’t sleep long enough, and will completely screw up my schedule.”
“My son has never napped since he developed N24. He will have periodic ‘catchup days’ when he sleeps for a really long time (I.E. over 12hrs in one stretch) but not naps.”
“Person does not need to adhere to a 24 hour schedule so does not need naps.”
“Naps can be any time, day or night. I primarily do not plan them, I simply ‘pass out’.”
“I can only nap when I am not using melatonin in the evening.”
“Any time I have ever tried to nap, my body tries to turn it into a full night’s sleep. I can’t just sleep for an hour or something.”
“Only nap if I am ‘forced’ to wake up (meaning, I interrupt my current sleep schedule)”
“No napping as long as my sleep doesn’t get messed up.”
“If I didn’t get at least 8 hours of sleep I feel the need to nap and every time I do the nap lasts from 2-4 hours.”
“I can only sleep when unemployed. This condition isolates me from my peers. I hate it.”
“I can also ‘pass out’ for some minutes whilst sitting in a chair. This usually happens when I’m sleep deprived or have a temporary illness.”
“Whenever I try to take a nap that is 2 hours or less I usually end up napping or lightly sleeping for much longer. Naps usually do not make me feel refreshed and sometimes I feel worse than I did before I tried to nap. To get good restful sleep I take sleep medicine (Lunesta) but I don’t take anything when I nap.”
“Eating too much or a lot carbs makes me nap. Siesta!”
“Completed on behalf of my 6 year old son.”
“I sometimes sleep on a bi-phasic schedule. typically 5 hours of sleep, then 5-7 awake, then 5 asleep again. This allows me to have more day time hours for work and social commitments but it comes at a price. It take 2 or more hours of ‘dark therapy’ to get to sleep each time, so I waste a lot of time laying in bed. (Thank god for podcasts!)
“While hard on my body physically, a week of sleeping bi-phasicaly is better socially and mentally then a week on the ‘graveyard shift’ when I never see the sun or other people.”
“I cannot sleep earlier than my habitual sleep onset, and if I somehow do (usually once or twice per year) then I usually sleep 3-5 hours with poor quality.”
“I wasn’t able to nap as a kid either.”
“I often only sleep short stretches at a time, and I frequently fall asleep/nap throughout the day any moment I have down time, in a desperate attempt to get enough total sleep to function. I was diagnosed DSPS by a sleep specialist and told not to nap, but I will literally fall asleep while standing/walking/talking if I get hit by a ‘sleep wall.’ Even just a few minutes will resolve it for a while, but I have to give it that much. I will struggle more to nap during my current ‘waking hours’ window than my current ‘sleeping hours’ regardless of how sleep deprived I am.”
“I wasn’t able to nap as a kid either.”
“If I’m tired enough to get to bed and fall asleep, then I usually sleep a full., [sic] which averages about 10.5 hours for me. Only on occasion am I able to rest for just a couple hours and then get back up again.”
“I try to avoid napping as it delays my cycle even more and I feel groggy after a nap. But if I haven’t slept enough in the current cycle, sometime I can’t function at all without a nap.”
“When I didn’t free run I had to make myself scared so that I didn’t fall asleep in the work place or school. The adrenaline from this fragments my sleep badly. I would not describe this as napping though, it is more like waking up many times in the night. When free running regularly enough there is no fragmentation and no napping is possible or necessary.”
“I have never really been able to nap, not even as a child. Whenever I tried, it just made me feel extremely fatigued and groggy for the rest of the day.”
“I also have Reverse Seasonal Affective Disorder, so my emotional & physical adaptation to seasons is screwed up too.”
“Naps are critical for me when maintaining any semblance of routines with standard clock; but it’s due to not being able to sleep in rhythm of my clock.”
This survey was anonymous and we did not collect respondent data. In each online location where the link to this survey was shared, it was explained that this survey was informal and therefore not protected by HIPPA, for example.
Interpretation of Napping Survey Data
34% of U.S. adults reported napping on a typical day [Pew Research].
… Only 18% of our sixty SN24 patients napped either daily or at least weekly.
80.7% of surveyed U.S. adults have taken a nap in the past three months [Sleep Foundation].
… This is only about 39% for SN24 patients, whether free-running or not.
In total, 55% of Sighted Non-24 patients surveyed said they cannot nap at all, cannot nap except for once every few years, or have napped fewer than 8 times in the past year. This could very likely increase up to 60% because the 5% of “other” responses for Question #4 also reported rarely napping or only napping with illness and exhaustion in their explanation text-box responses.
According to this self-reported informal study of these 60 respondents, around 60% of SN24 patients rarely nap or are completely unable to nap. If this data is correct, it indicates people with Sighted Non-24 are less likely to nap than the general public. While around 80 percent of the general public took a nap within the past three months, that number is approximately halved for Sighted Non-24 patients according to this survey.
Additional Thoughts on Napping Ability
The following is speculative and only mentioned for contemplation (and hopefully, future study).
Genetics? Among the chronotypical population, napping ability is also genetic and cultural. There are ethnic groups/sub-groups which have a higher prevalence of napping. Could it be possible that those without genetic predisposition for napping ability are more likely to have genetic mutations indicative of Sighted Non-24? There are currently no known pathogenic gene variants for Non-24, although some genetic studies are ongoing. PER3 gene variants influence sleep timing and depth; some people are genetically inclined to fall asleep faster.
Wake-Biased Chronotype? For people with a napping ability, there may be a natural dip in alertness in the early afternoon (around 1–3 PM for chronotypical people), making napping come easier; alternatively, people with a more “wake-biased” circadian rhythm may resist this dip, making naps harder.
Neurotransmitters? Neurotransmitters like GABA, serotonin, orexin, and histamine also regulate sleep-wake transitions. For instance, more active orexin signaling = more alertness. Orexin is a neuropeptide in two types: orexin-A and orexin-B. Orexin stabilizes the boundaries between sleep and wake states. Low orexin activity allows for easier transitions into sleep (like naps). High orexin activity increases the wakeful state and can block sleep onset. For example, Narcolepsy Type 1 is caused by a deficiency in orexin-producing neurons.
Adenosine? This inability to nap could have something to do with adenosine; for example, people who are able to nap easily may have higher adenosine sensitivity, faster adenosine buildup, an/or less resistance to sleep pressure.
Adrenal Component? Some people maintain high levels of cortical arousal, even when tired. For example, stress, anxiety, and an overactive HPA axis (hypothalamic-pituitary-adrenal) can block sleep onset. (The HPA Axis also needs a deep-dive study, especially where HPA Axis disruptors are involved, possibly leading to Sighted Non-24 and other circadian or sleep-related disorders). Those with adrenal issues might struggle to nap even if they’re exhausted as cortisol imbalances can leave people feeling wired-but-tired.
Personal Note from the SightedNon-24.org Admin
I wanted to run this survey after speaking to my half-sibling who is also unable to nap. I had previously started a discussion on this in the Non-24 Facebook group back in 2019 and this conversation re-ignited my curiosity. I have had Non-24 since my teenage years but was a DSPS/night owl type prior, my sibling has a DSPS/night owl type (unable to nap), our shared parent has DSPS/night owl type (unable to nap), and one of our grandparents had a DSPS/night owl chronotype (unsure of napping ability). My sibling’s adult child also has an interesting sleep rhythm, currently undefined. This suggests a strong genetic component in napping ability and chronotype. Including myself, five members of my biological family have contributed to an ongoing genetic study of circadian rhythm disorders. Additionally, I do not recall ever napping as a child and napping was not a part of my family’s daily structure. I did not detail this information prior to (or during) the survey collection to avoid skewing results toward fellow non-napping types.