The sudden shift in our circadian rhythm triggers a domino effect
Each spring, Ireland and much of the world surrender an hour of sleep to a practice born of Victorian pragmatism, and while the calendar moves on without hesitation, the human body does not. A health researcher is reminding us that this annual ritual — clocks advancing to British Summer Time on Sunday, March 29 — is not merely an inconvenience but a measurable disruption to the biological rhythms that govern our health, mood, and safety. The phenomenon she calls 'social jet lag' is a quiet collision between institutional time and the deeper clock we carry within us.
- At 1 a.m. this Sunday, Ireland loses an hour of sleep — and research shows the body will spend days trying to reclaim what the calendar simply erased.
- The spring change is harder on the body than the autumn return: we resist being forced awake earlier far more than we resist staying up late, making this shift uniquely disruptive.
- The stakes are not trivial — studies link the days following the spring clock change to measurable spikes in road accidents, heart attacks, strokes, cluster headaches, and anxiety.
- Health expert Loris Juett warns that the disruption cascades across the whole population simultaneously, compounding reduced alertness, metabolic imbalance, and mood disturbance at a societal scale.
- Experts are urging people to act now — shifting bedtimes gradually, eliminating screens before sleep, cutting caffeine and alcohol, and preparing their sleep environments to cushion the biological blow.
This Sunday at 1 a.m., Ireland's clocks spring forward by an hour — a ritual so familiar it barely registers, except in the body. Loris Juett, a scientific research expert at The Turmeric Co., is warning that the annual shift to British Summer Time carries consequences most people underestimate: disrupted sleep, heightened accident risk, and what she calls social jet lag.
The practice has roots stretching back to 1907, when British builder William Willett campaigned to shift the clocks and preserve daylight. The Summer Time Act of 1916 made it law, rooted in agricultural logic — farmers needed sunlight during the growing season. That reasoning has outlasted the farming era, and today we inherit longer evenings at the cost of one hour of sleep.
Juett describes the body's response as a domino effect. The circadian rhythm — the internal clock governing sleep, hormones, appetite, and metabolism — is jolted out of sync. Studies show people sleep around 40 minutes less on the Monday after the spring change, and that deficit correlates with measurable increases in traffic accidents, heart attacks, strokes, and anxiety. The disruption runs deeper in spring than in autumn, because the body resists being forced to wake earlier far more than it resists staying up late.
To ease the transition, Juett recommends shifting bedtime back by 15-minute increments over the four nights before the change, avoiding screens in the hour before sleep, cutting caffeine and alcohol for 48 hours around the shift, and optimising the sleep environment with controlled temperature and blocked light. Small adjustments, she suggests, that honour what the calendar ignores: the body keeps its own time, and overriding it always carries a cost.
This Sunday morning at 1 a.m., Ireland's clocks will spring forward by an hour. It's a ritual so familiar that most people barely notice the shift—except that their bodies will. A health researcher is now warning that the annual adjustment to British Summer Time carries real consequences: disrupted sleep, increased accidents, and a phenomenon she calls social jet lag.
The practice dates back more than a century. William Willett, a British builder, campaigned for it in 1907, convinced that moving the clocks would stop people from wasting daylight and conserve energy. The Summer Time Act of 1916 made it official. The logic was agricultural: farmers needed extra hours of sunlight during the growing season. Today, the reasoning persists, even though most of us no longer work the land. We gain longer evenings. We lose an hour of sleep.
Loris Juett, a scientific research expert at The Turmeric Co., describes what happens next as a domino effect. When the clocks advance, our circadian rhythm—the internal 24-hour clock that regulates sleep, hormones, appetite, and metabolism—gets jolted out of sync. The body doesn't simply adjust. Research shows that people sleep roughly 40 minutes less on the Monday following the spring change. That single hour of lost sleep correlates with measurable increases in road traffic accidents, heart attacks, and strokes. Cluster headaches spike. Anxiety surges. The disruption is sharper in spring than in autumn, when we gain an hour back, because our bodies resist being forced to wake earlier more than they resist staying up later.
Juett emphasizes that this isn't mere grogginess. The cascade of effects—reduced alertness, metabolic disruption, mood disturbance—compounds across the population. The statistics are there if you look for them.
To soften the blow, Juett offers practical guidance. In the four nights before the change, shift your bedtime backward in 15-minute increments, allowing your body to adjust gradually rather than all at once. In the hour before sleep, put screens away; the blue light suppresses melatonin production, the hormone that tells your body it's time to rest. Consider cutting caffeine and alcohol for 48 hours around the transition. And optimize your sleep environment: control the temperature, block out light, create the conditions your disrupted body will need to recover.
These are small interventions, but they acknowledge something the calendar ignores: our bodies have their own time, and forcing them to follow a different clock carries a cost.
Citas Notables
The sudden shift in our circadian rhythm triggers a domino effect of physical and psychological lag, linked to spikes in road traffic accidents, metabolic disruption, and cluster headaches.— Loris Juett, Scientific Research Expert at The Turmeric Co.
La Conversación del Hearth Otra perspectiva de la historia
Why does the spring change hit us harder than the autumn one? It seems like it should be symmetrical.
Because we're losing sleep, not gaining it. In autumn, we get an extra hour in bed. In spring, we're forced out of it. Our bodies resist waking earlier more than they resist staying up later—it's about the direction of the push.
And the accidents, the heart attacks—those aren't just correlation, are they? There's something real happening in the body?
The research is consistent. When you lose sleep and your circadian rhythm fractures, your alertness drops, your reaction time slows, your cardiovascular system is under stress. It's not dramatic for any one person, but across a population, the numbers move.
So why do we still do this? If we know it causes harm, why not just leave the clocks alone?
Inertia, mostly. The original reason—helping farmers—doesn't apply anymore. But the habit is over a century old. Changing it would require coordination across countries, and there's no consensus that the benefit of longer evenings outweighs the cost.
The 15-minute increments before the change—does that actually work?
It gives your body a chance to drift gradually rather than being yanked. It's not a cure, but it's gentler than the alternative. Same with the sleep environment stuff—you're just removing obstacles so your already-disrupted system has the best chance to recover.