One hour. That's all it is, technically. And yet every spring, without fail, Monday arrives and something feels off. You're tired in a way that doesn't quite match the amount of sleep you got. Your morning feels sluggish. Your body hasn't caught up.
That's not you being dramatic. That's your circadian rhythm - and it's worth understanding why it reacts the way it does.
Your body runs on light, not clocks
Your circadian rhythm is your internal 24-hour clock. It governs when you feel alert, when you feel sleepy, when your digestion wakes up, when your hormones peak. It's remarkably precise - and it's calibrated almost entirely by light.
Early morning daylight activates a small but critically important cluster of cells deep in the brain called the suprachiasmatic nucleus - the body's master clock. From there, it sends signals to timekeepers in almost every cell in the body, switching on the processes that prepare your organs for the day ahead.
The problem with spring is the direction of the shift. Moving the clocks forward means less light in the morning and more in the evening - the opposite of what your circadian rhythm needs to stay on track. Your biology is genuinely confused, and that confusion has real effects. Research shows hospital admissions increase right after the clock change, and many people lose sleep for a week or longer .One hour really does matter.
The two things researchers say actually help
There's good news. Scientists have identified two morning behaviours that help stabilise circadian rhythms through the transition - and they're both free.
The first is light. Getting outside in the morning - even on a grey British morning - gives your SCN the signal it needs to recalibrate. Indoor light typically isn't bright enough to reset internal clocks, so getting outside matters.
The second is movement. Exercise influences circadian rhythms through a different pathway than light. The peripheral clocks in oxygen-sensing organs like the muscles, which means combining morning light and movement may be more effective than either on its own.
In practical terms: a 20-minute outdoor walk in the morning is one of the most evidence-backed things you can do this week. Experts suggest starting a few days before Sunday, waking up 15 to 20 minutes earlier each day to ease your body into the shift gradually.
And on the other end of the day, bright light and late-night eating in the evening can push your rhythms in the wrong direction, undoing the work your morning routine is doing. Worth keeping in mind.
How to get ahead of it before Sunday
The good news is that a little preparation goes a long way. Experts suggest starting a few days before Sunday, waking up 15 to 20 minutes earlier each day to ease your body into the shift gradually. Small increments are much easier for your body to absorb than one sudden jump.
Can't shift your schedule in advance? A short nap of 15 to 20 minutes before 3pm on Sunday can take the edge off without interfering with your night sleep. Not a perfect solution, but a practical one.
The mineral your circadian rhythm quietly depends on
If there's one supplement to think about this week, it's magnesium.
It plays a direct role in melatonin production - the hormone that tells your body it's time to wind down, as well as nervous system calm and muscle relaxation. The kind of internal settling that makes sleep actually feel restful.
Research involving nearly 4,000 participants found that those with the highest magnesium intake were around 36% less likely to experience short sleep. That's not a small margin.
Most people don't get enough through diet alone, and the effects tend to be subtle: slightly disrupted sleep, low-grade fatigue, a general feeling of not quite recovering. During a week when your body is already working harder than usual to adjust, that gap matters more.
Our Marine Magnesium is sourced from the sea, which gives it a naturally high bioavailability - meaning your body can actually use it. It supports muscle function, reduces tiredness and fatigue, and helps your body wind down at night and wake up feeling more like itself in the morning.