Why Sleep Scientists Favor Permanent Standard Time, and How to Handle Dark Evenings

There is a particular Monday after the clocks go back. You look up from the kitchen counter, expecting the light to be doing what it did last week, and it is already gone. It is not even dinnertime. The day feels as if it ended early and nobody told you.

The clocks fell back on November 1, and this week a few more people are asking an old question: should we keep changing them at all? Sleep researchers have been fairly consistent on the answer. If we are going to pick one clock and leave it alone, it should be standard time. I want to walk through why they say that, be honest about where the evidence is thinner than the headlines suggest, and then give you something practical for the next two weeks of early darkness.

The solar-day argument

Your body keeps a roughly 24-hour internal rhythm, and the strongest signal that sets it is light, especially light early in the day. Standard time is the clock that lines up most closely with the sun: noon sits near the middle of the daylight, and morning light arrives at an hour when most people are awake and moving.

Permanent daylight saving time shifts everything an hour later relative to the sun. That sounds pleasant in July, with a long golden evening. In winter it means sunrise at a time when many people are already at work or school, and mornings that stay dark far longer. The circadian argument is that this mismatch between the social clock and the solar clock is the thing to minimize. The American Academy of Sleep Medicine made that case in its 2020 position statement, and it has not changed its mind.

What the recent papers found

Three recent pieces of work point the same direction. A policy analysis in CMAJ from researchers at the University of British Columbia, led by Lam, argues for permanent standard time. A systematic review in the European Journal of Epidemiology pulled together 157 studies from 36 countries. And a narrative review from UNLV, published in Brain Sciences, reaches a similar conclusion.

Here is the part worth slowing down on. The systematic review did not find a consistent, population-wide change in how long people sleep after the clocks change. Averaged across everyone, the shift is not a clean drop in hours slept. So I would be careful with any claim that the time change is simply making a whole country sleep less. The case for standard time rests on timing and alignment with the sun, not on a dramatic loss of sleep minutes.

That distinction matters, because it tells you what to do about it. If the problem were pure sleep quantity, you would fix it by going to bed earlier. If the problem is when your body gets light and darkness, you fix it with light.

Why bright mornings and dim evenings matter once it is dark by 5pm

When the sun sets around 5pm, the evening starts earlier but your bedtime does not. The hours between dusk and bed fill up with indoor lighting, which is usually far dimmer than daylight but still brighter than what your body expects at night. Overhead lights and screens in the late evening can push your internal clock later. Meanwhile the morning, especially if you commute before sunrise or work indoors, may offer very little bright light.

So the winter pattern many people fall into is a dim morning followed by a bright, stimulating evening. It is the reverse of what the clock likes. The fix is to reverse it back: get as much real daylight as you can early, and let the evening get quieter and warmer.

I have noticed this in my own house. When it gets dark early, every lamp comes on at once and the room turns into a stage, and an hour later I wonder why I feel wired at ten. Nothing dramatic happened. The room simply never told me the day was over.

Evening screens, briefly

I will not pretend a phone is the villain of every bad night. Screens matter through two routes: the light they emit, and what you do on them. A reply to a stressful message at 9:30pm does more harm than the blue tint. If you can only change one thing, change the content before the brightness. Then dim the device, turn on a night-shift style setting if you like it, and hold the phone farther from your face.

Night owls and early risers

The dark evenings do not land on everyone equally. Early risers often cope well. They are already up with the light and tired by the time the sun goes, so a 5pm sunset feels almost natural. Night owls tend to have a later internal clock, so for them the morning is the hard part: waking in the dark, with the body still insisting it is the middle of the night. They also tend to get their second wind in the evening, exactly when light is least helpful.

If you are an owl, spend your effort on the morning. Light in the first hour you are up does more for you than any evening habit. If you are a lark, protect your evenings from the temptation to stay up just because the house is lit.

A two-week dark-evenings routine

Two weeks is long enough to feel a difference and short enough to actually finish. Treat it as an experiment and notice what changes.

Week one: anchor the light

• Morning: go outside within an hour of waking, even for ten minutes, even if it is overcast. Outdoor light on a grey day is still much brighter than a room.
• Midday: if your work is indoors, take one short walk in daylight.
• Dinner: aim to finish eating at least two to three hours before bed. A big late meal competes with sleep.
• Evening: after sunset, switch from overhead lights to a couple of lamps.

Week two: build the wind-down

• Keep week one going. Do not drop the morning light.
• Set a screen edge: pick a time, perhaps an hour before bed, after which email and news are off.
• Add a small ritual: a warm shower, a few pages of a paper book, or ten quiet minutes of meditation. I use a short evening sitting from the Heartfulness practice, and the specific method matters less than doing the same thing at the same time.
• Hold your wake time steady, including the weekend, within about an hour.

At the end of the two weeks, ask one plain question: do I fall asleep faster, and do I feel more awake by mid-morning? If yes, keep it. If not, the routine is still harmless, and you have learned that your sleep trouble probably lives somewhere else.

FAQ

Does the time change make everyone sleep less?

Not on average, according to the large systematic review. It found no consistent population-wide change in sleep duration after clock changes. The stronger argument for standard time is about circadian alignment with the sun.

Why do experts prefer standard time over permanent daylight saving time?

Standard time matches the body clock more closely, with brighter mornings and earlier darkness. Permanent daylight saving time would push sunrise later in winter, leaving many people commuting and working before it is light. The AASM took this position in 2020.

Will I feel better if I just go to bed earlier?

Maybe a little, but light timing usually matters more than bedtime alone. Morning daylight and calmer evenings tend to help more than forcing yourself into bed before you are sleepy.

Is a light therapy lamp worth it?

For some people with dark mornings it can help, but try free daylight first. If low mood or exhaustion lasts well into winter, speak with a doctor rather than just buying a lamp.

The sun does not care what the clock says. Most of what helps in November is just agreeing with it a little more often.