Tonight we will lose an hour of our lives when we observe Daylight Savings Time (DST).
Media reports suggest that DST, beyond robbing of us that nocturnal hour in the spring are also increasing our risk of heart attack (myocardial infarction or MI) and death.
Is this a valid concern or just media hype on a slow news day?
Scientific studies on this topic are mixed.
A recent study from Finland found MI rates increased 16% on the Wednesday after spring DST time change and dropped by 15% on the Monday after fall DST time change.
A 2015 German study found no difference in MI rate in the 3days or 1 week after spring or fall DST transitions.
However, some American studies have detected a bump in MI rate on the day after DST transition in the spring and a similar drop in MI rate on the day after the fall DST change.
A study of 42000 patients undergoing acute PCI for MI in Michigan found that
“The Monday following spring time changes was associated with a 24% increase in daily AMI counts (p=0.011), and the Tuesday following fall changes was conversely associated with a 21% reduction (p=0.044). No significant difference in total weekly counts or for any other individual weekdays in the weeks following DST changes was observed.”
Our data argue that DST could potentially accelerate events that were likely to occur in particularly vulnerable patients and does not impact overall incidence. There is considerable controversy over the health and economic benefits of DST, and some authorities have argued that this practice should be abandoned.17 Although we are unable to comment on the merits of these arguments, our data suggest that while such a move might change the temporal fluctuations in AMI, it is unlikely to impact the total number of MIs in the broader population.
Mondays, in general, are the days of the week on which most MIs occur. This has been attributed to an abrupt change in the sleep–wake cycle and increased stress in relation to the start of a new work week
Manipulations of the sleep–wake cycle have been linked to imbalance of the autonomic nervous system, rise in proinflammatory cytokines and depression so presumably the additional disruption created by DST adds to this effect.
However, the data suggest that this very weak effect means only that if you were going to have an MI in the next week, after DST it is more likely to occur on the Monday of that week than on another day. Your overall risk of MI is not changed.
From a public health standpoint the major conclusion is that emergency rooms and cath labs should consider increasing staffing by 24% on the Monday after the spring DST time change.
I don’t think this is a significant factor for my patients. We have to deal with events and stressors that influence our sleep-wake cycle constantly. Good planning and sleep hygiene are the keys to success and reducing stress.
So, fear not the grim reaper as you set your clocks forward tonight.
PHOTO: PAVEL ŠEVELA/WIKIMEDIA COMMONS