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THE WAKE-UP CALL
3 a.m. Blanket off. Blanket on. Blanket off. Is it the hot flash, or is it everything else?
This week: a new drug trial on menopause and night waking, and what it can and can't tell you.
THIS WEEK IN SLEEP
A drug trial on night waking after menopause
In a small trial funded and run by the drugmaker Bayer, 110 postmenopausal women with at least 20 moderate to severe hot flashes a week and broken sleep took elinzanetant or a look-alike placebo for 12 weeks. Neither the women nor the study staff knew who got which. After 4 weeks, time awake at night, measured in a sleep lab, had dropped about 22 minutes more in the drug group than in the placebo group. By week 12, that gap had shrunk to about 1 minute, mostly because the placebo group kept improving. Limits: this was an early (phase 2) trial in women ages 40 to 65 without other common sleep disorders such as sleep apnea, and it was designed to estimate effects, not to formally test them. Extra analyses pooling all 12 weeks leaned toward the drug, but they were not planned in advance.
THE DEEP DIVE
Why the placebo group caught up
Why would a placebo group keep getting better? In an editorial in the same journal issue, three sleep researchers in Australia who were not part of the trial offer possible reasons: expecting to improve, the routine of keeping a daily sleep diary and paying closer attention to sleep, the effect of simply being observed, natural recovery, and the fact that people tend to join a study when their sleep is at its worst, then drift back toward their usual. These are possible explanations, not things this trial tested.
Three ways to measure sleep
The trial measured sleep three ways: two nights in a sleep lab at each checkpoint, a contactless sensor at home (84 of the 110 women), and a daily diary. The results did not line up perfectly. Total sleep time, for example, favored the drug in the lab but not on the home sensor or in the diary.
What the FDA label says
In the US, the FDA approved elinzanetant (sold as Lynkuet) in October 2025 to treat moderate to severe hot flashes due to menopause. It is not approved as a sleep medicine. Its label warns about sleepiness and dizziness that can affect driving, calls for liver blood tests before starting and 3 months in, and warns about seizure risk, a warning that was broadened in an August 2026 label update.
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REALITY CHECK
"Hot flashes explain all the night waking"
Myth: hot flashes explain all the night waking. A look back: in a small 2014 sleep lab study of 34 women in perimenopause, time awake linked to measured hot flashes made up about a quarter (27%) of their time awake at night, on average, with big swings from night to night. The authors counted conservatively, so the true share may be higher. Hot flashes matter, but they are not the whole story. Funded by the NIH.
NIGHT SHIFT
A new guideline for shift work disorder
The American Academy of Sleep Medicine published a new guideline on October 24 for treating adults diagnosed with shift work disorder. Every recommendation is a conditional "we suggest," and most rest on very low certainty evidence, much of it from lab simulations with healthy volunteers. One example: for sleepiness on the night shift, it suggests a snack or no food rather than a full meal, based on four small lab studies in healthy adults, with a caution for people who should not fast, such as those with type 1 diabetes. These are guidelines for clinicians treating a diagnosed condition, not rules for every night shift worker. Funded by the AASM.
WORTH A SMILE
Some birds nap on the wing. In a 2016 study (a look-back), researchers recorded brain activity in female great frigatebirds on flights of up to 10 days over the Pacific. The birds slept in flight, sometimes with one half of the brain at a time, mostly while circling in rising air. They also slept far less than on land: about 40 minutes a day. The study (free full text)
No brain, still needs a break. Upside-down jellyfish have no centralized brain, yet in a 2017 lab study (a look-back) they showed a sleep-like state: quieter and slower to react at night, and sluggish the day after their nighttime rest was disrupted. The study (free full text)
ONE LAST THING
Clocks fell back an hour at 2 a.m. today (Hawaii and most of Arizona: no change).
And a question for you: when you judge your own night, what do you trust most?
A. How I feel in the morning.
B. My tracker or app.
C. The clock on the nightstand at 3 a.m.
Reply with A, B or C. This is a conversation starter, not a scientific survey.
SOURCES
Baker FC, Joffe H, Soares CN, Maki PM, Bajbouj M, Nappi RE, Zammit G, Caetano C, Krahn U, Shalhoub H, Kramer F, Radcliffe H-S, Seitz C (2026). Elinzanetant in postmenopausal women with sleep disturbance: results from the randomized, phase II NIRVANA study. Sleep 49(10): zsag208. https://doi.org/10.1093/sleep/zsag208 Free full text: PMC13658252. Registered as NCT06112756. Funded by Bayer CC AG; the sponsor was responsible for design, conduct, analyses and reporting. Six of the 13 authors are Bayer employees, and most of the academic authors report consulting for Bayer.
Lappin JM, Perrault AA, Gordon CJ (2026). Elinzanetant improves sleep in postmenopausal women. So does placebo. Sleep 49(10): zsag210. https://doi.org/10.1093/sleep/zsag210 Editorial (opinion). The authors report nothing to disclose.
US Food and Drug Administration. Drug Trials Snapshot for elinzanetant. fda.gov Approval date: October 24, 2025.
Elinzanetant prescribing information, revised August 2026. DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f42884ff-7dff-419c-8a0c-affe2ed73818 Sections 1, 5.1, 5.2 and 5.4.
de Zambotti M, Colrain IM, Javitz HS, Baker FC (2014, look-back). Magnitude of the impact of hot flashes on sleep in perimenopausal women. Fertil Steril 102(6): 1708-1715.e1. https://doi.org/10.1016/j.fertnstert.2014.08.016 Cross-sectional sleep lab study; community sample. Funding: NIH. Fiona Baker, the last and corresponding author here, is also the first author of the NIRVANA trial.
Wright KP Jr, Abbott SM, et al. (2026). Management of shift work disorder: an American Academy of Sleep Medicine clinical practice guideline. J Clin Sleep Med 22(1): 202. https://doi.org/10.1007/s44470-026-00084-w Free full text: PMC13695634. Funded by the AASM.
Rattenborg NC, Voirin B, Cruz SM, Tisdale R, Dell'Omo G, Lipp HP, Wikelski M, Vyssotski AL (2016, look-back). Evidence that birds sleep in mid-flight. Nat Commun 7: 12468. https://doi.org/10.1038/ncomms12468
Nath RD, Bedbrook CN, Abrams MJ, Basinger T, Bois JS, Prober DA, Sternberg PW, Gradinaru V, Goentoro L (2017, look-back). The jellyfish Cassiopea exhibits a sleep-like state. Curr Biol 27(19): 2984-2990.e3. https://doi.org/10.1016/j.cub.2017.08.014
American Academy of Sleep Medicine, Sleep Education. Daylight saving time (states and territories that do not observe it). https://sleepeducation.org/resources/daylight-saving-time/
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The Sleep News provides general information, not personal medical advice. If sleep problems persist or affect safety, seek qualified medical care.
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