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Richard N. Fogoros, M.D.

Does Daylight Saving Time Cause Heart Attacks?

By November 1, 2013

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Now that we're saying goodbye to Daylight Saving Time for another 6 months, perhaps (according to researchers reporting in the New England Journal of Medicine), we'd be better off saying goodbye forever. That's because, they say, there is an association between switching to DST in the spring, and heart attacks.

Do we really need to add Daylight Saving Time to the long list of useful, enjoyable or fattening pleasures of life that we're supposed to give up? Read about it here.

February 17, 2009 at 5:16 am
(1) Blackjack UK says:

there is a link between sleep deprivation and cardiovascular problems.sleep deprivation-an extremely common and almost “normal” phenomenon in modern society – occurs randomly among the population.observe and measure the effects of sleep deprivation across a large number of people. When we do so, we can see that sleep deprivation, in general, poses health risks.i think so its a good question so thanks for this great article.

March 8, 2009 at 9:12 am
(2) waynesgarden says:

“Does this mean that daylight savings time is a public menace and should be abandoned? No. (As an Ohio farmer once explained to me, his corn crop really appreciates the extra hour of sunlight provided by DST.)…But for the sake of our corn crops and the cars that run on them, we should probably leave DST alone.”

Has it occured to the Doctor that our manipulation of our clocks does not increase the daylight one second more than Ma Nature gives us on any particular day?

March 8, 2009 at 9:18 am
(3) heartdisease says:

Some people appreciate irony, others do not.

December 29, 2009 at 11:31 am
(4) Gerald Oros says:

Me thinks the Ohio Farmer is pulling the good doctor’s leg since DST, will never, not by one iota, ever change the the amount of daylight the corn field receives on any given day

For me, the irony is that the findings of this interesting study do not go anywhere near the significance of the diurnal fluctuation of endothelial function, especially for its effect on high risk patients who are herded into invasive surgical procedure each morning. Pull up the abstract to “Early Morning Attenuation of Endothelial Function”.



October 28, 2010 at 9:28 pm
(5) gh says:

Stop the time change madness! Ridiculous vestigal modern day waste of energy, we might as well maintain hitching posts in front of every saloon. Keep only the summertime time.

November 1, 2010 at 9:05 am
(6) Rose P. says:

I believe we should keep one or the other year round. Changing the clocks is annoying & other that a little more sunlight or darkness in each case, it serves absolutely no purpose.

November 1, 2010 at 10:43 am
(7) Gord R. says:

Gerald O brings forth an excellent point. The morning of surgery, folks are awakened much earlier than otherwise – duplicating the DST onset effect – and as if that’s not bad enough, anxiety can cause poor sleep the night before, and as well, MIs have always peaked in the first 2 hours of wakefulness due to endothelial dysfunction. Nasty combination indeed. Should high-risk surgical candidates all undergo preparatory EECP well in advance to promote potentially compensatory angiogenesis before surgery??

November 1, 2010 at 11:14 am
(8) Gord R says:

Further to my earlier remarks, if one reads Gerald’s message #810 in the EECP Yahoo Group, the preparatory EECP treatments I suggest as a possible aid ought to be done in late morning or afternoon. I laud his insightfulness, and his recommendation that the time of EECP treatment be a mandatory part of the treatment record and that a study be done on accumulated data including treatment time to ensure treatment times are scheduled at times that minimize risk to patients.
Also, for ‘gh’ – comment (5), the extension of the DST interval a few years back was done to conserve energy. Diurnal variations in energy consumption patterns were studied and it was found that an extension by changes at both ends would produce significant savings. There was a purpose served, though at what added risk to humans and at what cost to human healthcare? Do reductions in CV events and associated costs at the end of DST entirely offset effects at the onset. How do families of fatal DST-onset-MIs feel about DST and should that human cost not be considered?

November 1, 2010 at 11:33 am
(9) Jan. says:

What difference does it make to the Corn Crops? They are outside, and are not aware, anyway, of time changes!!!

Altering time serves no useful purpose, and can only add to SAD Syndrome.

For those on strict medical routines, it causes complete disruption to their lives.

I detest it when the time is altered; it should be stopped.

October 27, 2011 at 10:38 am
(10) cathartes says:

The comment by the farmer was a joke. The farmer lives by the sun and seasons, not the clock. He understands the foolishness of manipulating the time. I enjoyed the article since I never gave much thought about how time changing affects us. I do hear people complain about how tired they are because they “lost” an hour in the Spring. I don’t feel the difference because it’s just one hour, not the same league as when traveling across many time zones.

October 31, 2011 at 12:56 pm
(11) S Nelson says:

While not specifically on the DST topic, readers & Dr Rich might be interested in a related and potentially very important recent study on the difference between morning-time hypertensive medication dosing versus bed-time dosing. In this trial, those who took their blood pressure medications at bed-time had a 70% (!) reduction in MIs, strokes, deaths compared to those who took them in the mornings! 70%!

See: “Bedtime Dosing of Antihypertensive Medications Reduces Cardiovascular Risk in CKD,” Ramón C. Hermida, Diana E. Ayala, Artemio Mojón, and José R. Fernández; Journal of the American Society of Nephrology, JASN Oct 24, 2011 ASN.2011040361.
See also: www(dot)theheart(dot)org/article/1247083(dot)do

Is such a significant difference in such a simple and costless thing plausible?
It has been known for a while that MIs happen disproportionally in the hours after waking and that there are physiologically-plausible reasons for this.
See, e.g., Am J Cardiol. 1992 Jul 1;70(1):65-8. Increased onset of sudden cardiac death in the first three hours after awakening.
and: Circulation. 2004; 109: 2507-2510. Early Morning Attenuation of Endothelial Function in Healthy Humans.

Perhaps Dr Rich should write a summary on this topic?
The BP medication dosage timing issue needs way-wider distribution.

October 31, 2011 at 1:08 pm
(12) S Nelson says:

P.S. Another good background source on this topic is:
“Morning Surge in Blood Pressure and Cardiovascular Risk : Evidence and Perspectives,” Kazuomi Kario. Hypertension 2010, 56:765-773: originally published online October 11, 2010 doi: 10.1161/HYPERTENSIONAHA.110.157149. Available at:
[i.e. no "www"]

October 31, 2011 at 3:49 pm
(13) rhythmdoc says:

DrRich is a genius…and his continued efforts to demystify, decentralize, and democratize medicine will, on occasion, only confuse those less prepared. Go, doctor, go.

November 4, 2011 at 11:44 pm
(14) Gerald Oros says:

A big thank you to S Nelson for bringing attention to the
startling findings in the study:

“Bedtime Dosing of Antihypertensive Medications Reduces Cardiovascular Risk in CKD,” Ramón C. Hermida, Diana E. Ayala, Artemio Mojón, and José R. Fernández; Journal of the American Society of Nephrology, JASN Oct 24, 2011 ASN.2011040361.
See also: www(dot)theheart(dot)org/article/1247083(dot)do

Gerald Oros


November 15, 2011 at 1:15 pm
(15) S Nelson says:

Appreciated, Gerald Oros.

Another cite, this one on the benefits of bedtime dosing of ARBs, for blood pressure control would be: http[colon]//www[dot]ncbi[dot]nlm[dot]nih[dot]gov/pmc/articles/PMC1936293/pdf/tcrm0301-119[dot]pdf

“Abstract: Some specific features of the 24h blood pressure (BP) pattern are linked to the progressive injury of target tissues and the triggering of cardiac and cerebrovascular events. In particular, many studies show the extent of the nocturnal BP decline relative to the diurnal BP mean (the diurnal/nocturnal ratio, an index of BP dipping) is deterministic of cardiovascular injury and risk. … Thus, bedtime dosing with nifedipine gastrointestinal therapeutic system (GITS) [i.e. ARBs] is more effective than morning dosing, while also reducing significantly secondary effects.”

Again, this phenomena needs much better physician & patient appreciation…

May 28, 2012 at 2:33 am
(16) additional info says:

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November 12, 2012 at 10:28 am
(17) Sue says:

I like my DST! It’s the switch back in the Fall that kills me.

November 13, 2012 at 11:30 pm
(18) tryphone kagaruki says:

i have question;why in rheumatic endocarditis and infective endocarditis the mitral valve is the most affected?.

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