An Evening Routine for Better Sleep After 40

Sleep after forty tends to get lighter and more easily interrupted, but the amount you need does not shrink. This briefing sets out an evening routine drawn from the CDC's and the American Academy of Sleep Medicine's sleep-hygiene guidance, in a sensible order, and then looks honestly at where magnesium or melatonin would fit.

What changes after 40, and what does not

The National Institute on Aging puts it plainly: older adults need about the same amount of sleep as all adults, seven to nine hours a night, but they tend to go to bed earlier and wake earlier, sleep is often shorter and lighter, and waking during the night becomes more common. Older adults are also more likely to take medicines that affect sleep. The CDC's figures run the same way: seven or more hours for adults 18 to 60, seven to nine for 61 to 64, and seven to eight for 65 and over. In the CDC's 2022 data, 39 percent of adults aged 45 to 64 reported sleeping less than seven hours.

So the goal for a healthy adult past forty is not to sleep like a teenager. It is to protect a seven-hour window and to stop doing the ordinary things that shorten it. Everything below is for that healthy adult. Sleep trouble that persists for weeks is a conversation with a clinician, not a supplement decision; we come back to that at the end.

The routine, step by step

1. Start from the wake time and count back. The American Academy of Sleep Medicine's list begins with a fixed wake time, weekends and vacations included, and a bedtime early enough to allow at least seven to eight hours. The National Institute on Aging adds "even when traveling." An evening routine is built backward from the alarm, so decide the alarm first; if it rings at 6:30, lights-out by about 11:00 protects a seven-and-a-half-hour window.
2. Move during the day, and finish early. The Physical Activity Guidelines for Americans note that improved sleep is one of the benefits that can appear immediately after a single session of moderate-to-vigorous activity, and that regular activity is linked with deeper sleep over time. A meta-analysis of 66 studies in the Journal of Behavioral Medicine found regular exercise had small benefits for total sleep time and sleep efficiency and moderate benefits for sleep quality. The timing matters: the CDC's occupational-safety institute and the National Institute on Aging both advise finishing exercise at least three hours before bed.
3. Set the caffeine cut-off, then honor it. In a small trial of 12 healthy sleepers in the Journal of Clinical Sleep Medicine, 400 mg of caffeine, roughly two to three 12-ounce cups of brewed coffee, taken six hours before bedtime cut objectively measured sleep by more than an hour, while the participants' own sleep diaries showed a smaller loss (about 41 minutes) that did not reach statistical significance. In other words, they largely did not notice. The CDC's occupational-safety institute says five or more hours before sleep; a 2023 meta-analysis in Sleep Medicine Reviews put the cut-off for a single cup of coffee at 8.8 hours; the American Academy of Sleep Medicine says simply to avoid caffeine in the afternoon and evening. The National Institute on Aging reminds readers that tea, chocolate and soda count. For an 11:00 bedtime, an early-afternoon cut-off satisfies all of them.
4. Dim the house about three hours before bed. The 2022 expert consensus on indoor light in PLoS Biology recommends that from at least three hours before bedtime, light at the eye stay below about 10 lux of daylight-equivalent "melanopic" light, which in practice means lamps rather than ceiling lights, and warm bulbs rather than bright white. Screens are a special case. In a small laboratory study in PNAS, adults who read on a light-emitting e-reader in the hours before bed took longer to fall asleep, felt less sleepy in the evening, showed a later shift in their body clock and were less alert the next morning than when they read a printed book. The CDC and the American Academy of Sleep Medicine both say to turn off electronic devices at least 30 minutes before bed; the printed book is the simplest substitute.
5. Make the room cool, dark and quiet. The CDC's occupational-safety institute suggests a comfortably cool room, about 65 to 68 °F for most people, and a sleep environment that is "very dark, quiet, cool, and comfortable." The PLoS Biology consensus asks for the sleep environment to be as dark as possible, at most about 1 lux, with dim light of no more than 10 lux if you need to see during the night. Blackout blinds, a nightlight in the hallway rather than where you sleep, and the phone charging in another room cover most of it.
6. Eat and drink earlier. Heavy or spicy meals within three hours of bedtime are on the CDC occupational-safety institute's list to avoid; the National Institute on Aging says large meals within two to three hours, and the American Academy of Sleep Medicine allows a light snack if you are hungry. On alcohol, the CDC and the Academy both say to avoid it before bedtime, the occupational-safety institute suggests finishing any drink several hours before bed, and the National Institute on Aging's list says to avoid alcohol, even small amounts. Both the Academy and the Institute also advise tapering fluids in the last hours, which matters more after forty than it did before.
7. Give yourself a wind-down window, and a rule for wakeful nights. The CDC's occupational-safety institute suggests a relaxing routine for the last hour and a half; the National Institute on Aging suggests a book, quiet music or a warm bath. Then two rules from the American Academy of Sleep Medicine: do not go to bed unless you are sleepy, and if you are not asleep after about 20 minutes, get up and do something quiet in low light, without electronics, until you are. Naps late in the afternoon or evening spend the sleep pressure you will want at 11:00, so the Institute advises against them.

One version of the evening

Working back from a 6:30 alarm: the last coffee is finished by early afternoon; the walk, class or gym session is done by 8:00; dinner is on the table by 8:00 as well, with water rather than a second glass of wine. From about 8:00 the ceiling lights go off and the lamps come on. Screens are put away by 10:30, and the phone goes to charge in the kitchen. The room has been cooled toward 65 to 68 °F and the blinds are down. At 10:45 there is a printed book in a dim lamp, and bed when sleepy rather than by the clock. If sleep has not come by 11:20, it is back to the chair and the book, not to the phone. The morning half of this same clock, light and movement soon after waking, is in Briefing B-01.

Where a supplement would even fit

Two supplements dominate the sleep aisle, and neither belongs ahead of the seven steps above. Here is what the sources say about each, in neutral terms.

Magnesium

The NIH Office of Dietary Supplements (ODS) puts the recommended intake for adults over 50 at 420 mg a day for men and 320 mg for women, most of it expected from food such as leafy greens, legumes, nuts, seeds and whole grains. The upper limit for magnesium from supplements and medicines is 350 mg a day; it does not count magnesium in food. The evidence for sleep is thin. A 2021 systematic review in BMC Complementary Medicine and Therapies found only three randomized trials, 151 older adults in total, in which people taking magnesium fell asleep about 17 minutes sooner than on placebo; total sleep time was about 16 minutes longer but not statistically significant, and the reviewers rated every trial at moderate-to-high risk of bias and the evidence as low to very low quality. On the practical side, the ODS notes that high doses from supplements can cause diarrhea, nausea and cramping, most often with the carbonate, chloride, gluconate and oxide forms, and that magnesium should be separated from oral bisphosphonates by at least two hours and from tetracycline or quinolone antibiotics by two hours before or four to six hours after. Report R-06 reads a glycinate lysinate chelate label against these numbers, and Briefing B-04 explains the forms.

Melatonin

Melatonin is a substance the body itself makes in response to darkness, which is why step 4 above matters more than any tablet. The NIH's National Center for Complementary and Integrative Health summarizes the research this way: it may help with jet lag after eastward flights; the evidence for shift workers is inconclusive; and for ongoing trouble sleeping, professional guidelines have found the evidence not strong enough to recommend it, preferring behavioral approaches. Short-term use appears to be safe for most people; the mild side effects reported in studies include headache, dizziness, nausea and sleepiness. The same page notes that because melatonin is sold as a dietary supplement in the United States, the content of products has often not matched the label: in one analysis of 31 products, the amount did not match the label for most of them, and a separate check of gummies found 22 of 25 inaccurately labeled, one with none detectable and the rest at 74 to 347 percent of the label amount. It adds that melatonin may stay active longer in older people and cause daytime drowsiness, that anyone taking medicine should consult a health care provider first, and that people with epilepsy or taking blood thinners need medical supervision. Report R-07 looks at a 3 mg tablet, the "start low" principle, and what a USP Verified mark does and does not tell you.

Ashwagandha

Sold with "stress" and sleep wording, this root extract comes in several standardizations that do not all match the ones used in trials. Report R-08 reads which extract is on one popular label, and sets out the pregnancy and medicine cautions.

Sources

1. National Institute on Aging. Sleep and older adults: how aging affects sleep and tips for getting a good night's sleep. link
2. Centers for Disease Control and Prevention. About sleep: recommended hours by age and habits for better sleep. link
3. Centers for Disease Control and Prevention. FastStats: sleep in adults, short sleep duration by age group, 2022. link
4. American Academy of Sleep Medicine, Sleep Education. Healthy sleep habits (reviewed August 2020). link
5. CDC, National Institute for Occupational Safety and Health. Science bulletin: tips to improve your sleep, June 2020. link
6. U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion. Physical Activity Guidelines for Americans, 2nd edition (full PDF). link
7. Journal of Behavioral Medicine, 2015. Meta-analytic review of the effects of acute and regular physical activity on sleep (66 studies). PubMed record. link
8. Journal of Clinical Sleep Medicine, 2013. Trial of 400 mg caffeine taken 0, 3 or 6 hours before bedtime in 12 healthy sleepers (PubMed Central full text). link
9. Sleep Medicine Reviews, 2023. Systematic review and meta-analysis of caffeine and subsequent night-time sleep (24 studies). PubMed record. link
10. PLoS Biology, 2022. Expert consensus recommendations for daytime, evening and nighttime indoor light exposure in healthy adults (PubMed Central full text). link
11. Proceedings of the National Academy of Sciences, 2015. Laboratory comparison of evening reading on a light-emitting e-reader versus a printed book: sleep onset, circadian timing and next-morning alertness. PubMed record. link
12. National Institutes of Health, Office of Dietary Supplements. Magnesium fact sheet for health professionals. link
13. BMC Complementary Medicine and Therapies, 2021. Systematic review and meta-analysis of oral magnesium supplementation for sleep complaints in older adults (three trials, 151 participants). PubMed record. link
14. National Center for Complementary and Integrative Health. Melatonin: what you need to know. link

This briefing is educational and is not medical advice. Ask a qualified clinician before changing a routine or starting any supplement.