Researchers reveal why jet lag works differently after 40

The first long-haul flight after 40 often lands with a strange double hit: you arrive tired, yes, but also oddly “wired”, as if sleep has become a negotiation rather than a switch. Researchers point to of course! please provide the text you would like me to translate. and of course! please provide the text you would like me to translate. as shorthand for the two systems that matter most here: your internal body clock and the sleep pressure that should pull you back into rhythm. It matters because jet lag isn’t just an inconvenience anymore; for many people it starts to spill into mood, digestion, performance at work and even how safe you feel behind the wheel.

The new finding isn’t that ageing makes you “bad at sleep”. It’s that the mechanisms that reset after a time-zone jump change subtly with age, and those small shifts add up over a week of early meetings, hotel curtains that don’t quite close, and caffeine used like scaffolding.

What jet lag really is (and why it stops behaving)

Jet lag is a misalignment problem. Your brain’s master clock in the hypothalamus is still running on “home time”, while your watch, your meal times and the daylight outside demand something else. Your body can cope with one late night; it struggles when every cue disagrees.

Two forces do most of the heavy lifting:

• Circadian rhythm: the internal clock that times alertness, temperature, hormones and sleep.
• Sleep pressure: the build-up of need for sleep across the day, which should peak at night.

After 40, research suggests the clock is often less flexible and the signals that anchor it-especially light-don’t land with the same punch. Sleep pressure still builds, but it may not translate into deep, consolidated sleep as reliably, which is why people report being exhausted yet waking at 03:00 wide awake.

Jet lag feels harsher not because you “can’t handle travel”, but because the cues that normally re-sync you are weaker and the recovery sleep is more fragile.

The age-related shifts researchers keep seeing

No single factor explains every bad week abroad. But several changes become more common in midlife, and they interact badly with time zones.

1) Light becomes a less powerful reset button

Your circadian clock uses morning light as a strong “set” signal. With age, the eye’s lens transmits less blue light and the pupil may narrow, meaning less of the most effective wavelength reaches the receptors that talk to the body clock.

Practical effect: the same sunrise that snaps you into a new schedule at 28 can feel like a mild suggestion at 48, especially if you’re indoors, commuting in low light, or wearing sunglasses all day.

2) Melatonin timing can drift

Melatonin isn’t a sleeping pill; it’s a timing hormone. It tells your system that night is beginning. Studies often find that melatonin secretion can shift earlier with age and the amplitude (the “signal strength”) can reduce.

That can produce the classic pattern: you feel sleepy too early, wake too early, and struggle to shift later when you fly west. When you fly east, you may feel tired at the “wrong” times but still not sleep deeply enough to bank recovery.

3) Sleep becomes lighter and more interruptible

Even in healthy adults, deep slow-wave sleep tends to decline with age. That matters during jet lag because you’re trying to use sleep as a repair tool while your body is confused, stressed and often dehydrated.

Add hotel noise, unfamiliar beds, alcohol on the flight, and a late meal, and the night fractures. Fragmented sleep doesn’t clear sleep pressure as effectively, so you start the next day already behind.

4) Routine anchors matter more than you think

The circadian system doesn’t listen only to light. It also responds to timed meals, exercise, and social schedule. After 40, people are more likely to have fixed commitments (work calls, caring duties, medications) that keep “home-time” habits alive, even while abroad.

You can end up with a split life: daylight says “new time zone”, dinner says “home”, and your inbox says “wake up at 02:00 for a call”. The clock hears all of it.

Why it can feel worse even when you travel the same way

Many travellers insist they do “the exact same routine” they did in their thirties. The body disagrees, because the context has changed.

Common amplifiers in midlife include:

• More caffeine sensitivity (or simply more caffeine use to cope).
• More alcohol impact on sleep (one drink can fragment sleep for some people).
• More stiffness and less movement on flights, which can worsen daytime fatigue.
• More baseline stress, which raises arousal and makes early wakes stick.

None of this is moral failure. It’s physiology meeting logistics.

A simple plan that tends to work better after 40

You don’t need a biohacking spreadsheet. You need a few well-timed cues, done consistently, and fewer self-inflicted sleep disruptions.

Before you fly: choose what you’re optimising for

If the trip is short, it can be easier to stay closer to home time. If it’s longer than three or four days, shifting usually pays off.

A practical pre-flight checklist:

• Pick one goal: shift fully, or cope temporarily on home time.
• Move bedtime by 30–60 minutes for 2–3 days if you can (towards destination).
• Bank sleep the week before; one extra hour helps more than you think.

During the first 48 hours: use light like medicine

Light timing depends on direction of travel, but the principle is stable: get bright light when you want your body to think it’s day, and reduce it when you want “night” to arrive.

• Eastbound (harder for many): prioritise morning light at destination; dim evenings.
• Westbound: get late-afternoon/early-evening light; keep mornings gentler if you’re waking too early.

If you can’t get outdoors, sit near a bright window. Indoor lighting is often too weak to act as a strong signal.

Sleep support that doesn’t backfire

People often reach for the strongest thing in the minibar. That usually buys a faster sleep onset and a worse second half of the night.

More reliable options:

• Keep naps short (15–25 minutes) and early; avoid late-day naps that steal night sleep.
• Hydrate and eat lightly on arrival; heavy meals at 22:00 are jet lag fuel.
• Use melatonin carefully if you already tolerate it: small doses can help with timing, but it’s not a universal fix and can cause grogginess in some people.

The goal isn’t perfect sleep on night one. It’s a strong day-night pattern by day two or three.

When jet lag stops being “normal”

Most jet lag fades as your cues align. But if travel routinely triggers severe insomnia, palpitations, low mood, or persistent exhaustion beyond a week, it’s worth discussing with a GP-especially if snoring, breathing pauses, hot flushes, or anxiety are in the background.

Sometimes the “jet lag problem” is really an unrecognised sleep disorder, perimenopause-related sleep disruption, or medication timing that clashes with travel schedules.

FAQ:

• Does jet lag really get worse after 40, or do we just notice it more? Many people do notice it more, but research points to real physiological changes-light sensitivity, melatonin timing, and lighter sleep-that can make re-synchronising harder.
• Is flying east always worse? Often, yes, because you’re asking your body to fall asleep earlier than it wants to. Westbound travel tends to align with the natural tendency to drift later, though early waking can still be an issue.
• Should I use sleeping tablets on the flight? Only with medical advice. They can help some people but may worsen grogginess, falls risk, and disorientation-issues that can matter more with age and dehydration.
• What’s the single most useful thing to do on arrival? Get well-timed outdoor light and keep meal times consistent with the local day. Those cues together usually shift the clock faster than trying to “force” sleep.