The Case Against the Clock Change

The biannual clock change is often treated as a minor inconvenience, but the scientific evidence shows that it produces real and measurable harm. The systematic review Daylight‑Saving Time and Health: A Systematic Review of Beneficial and Adverse Effects examined 149 studies from 36 countries and found consistent negative outcomes linked to the spring transition. The authors state that "DST onset transitions increase risk of acute myocardial infarction and fatal traffic accidents". This is not a small effect. It is a predictable health burden created by policy rather than biology.

The mechanism is simple. The spring shift forces millions of people to lose sleep at the same time. Sleep loss is not evenly distributed. People with early school or work start times are hit hardest. The review shows that sleep duration decreases after the spring transition and that circadian timing is disrupted. This is why heart attack rates rise immediately after the clocks move forward.

Traffic safety follows the same pattern. Fatigue and circadian misalignment reduce reaction time and increase human error. The review identifies a clear increase in fatal crashes after the spring switch. These deaths are not caused by weather or infrastructure. They are caused by a forced shift in human physiology.

The fall transition appears less harmful, but the overall pattern is clear. The spring clock change produces health risks with no meaningful benefit. The evidence shows that the time switch is not simply annoying. It is harmful, unnecessary, and out of alignment with what we know about circadian biology.

Ending the clock change would be a straightforward improvement to public health. The science is already clear. The policy has not caught up.