Heart Attack Risk Rises In Daylight Saving Time
Turning The Clock Forward Raises the Risk of Myocardial Infarction
Feb 25, 2009
With the turning of clocks forward, this year on March 8, 2009, those with an increased cardiac risk should be vigilant in maintaining sleep cycles and limiting stress.
The New England Journal of Medicine recently published (October 2008) a study documenting an increased risk of myocardial infarction (heart attack) occurring just after the change to daylight savings time in the spring.
Daylight Savings Time And Myocardial Infarction Swedish Study Results
The study, run by physicians Janszky and Ljung from the Karolinska Institutet in Sweden, examined patient records dating back to 1987 and found the following:
- a small increase (5%) in the risk of heart attack in the first three days of the new week after springing forward to daylight savings time.
- a small decrease (a reversion, although not as significant as the risk in March, for the entire following week) in risk when clocks are turned back in the Fall (this year occurring on November 1,2009).
The authors commented that the probable cause of this risk was a combination of the following:
- the disruption in the chronobiological rhythms
- the loss of one hour of sleep in the days immediately following the clock turn
- resulting sleep disturbances with the overall time adjustment
The researchers also commented that generally, myocardial infarctions are most common on Mondays and that sleep disturbances coupled with the resultant stress, caused by anticipation of work to perform within the week, must be considered when examining the results of the study.
Areas Not Participating In Daylight Savings Time (2009)
Most areas of the world are impacted with the seasonal change this year (some areas referring to it as Summer Time or Summer Hours).
The following are some areas that will not:
- Hawaii
- Arizona
- Marlana Islands
- British Indian Ocean Territory
- Virgin Islands
- Northern Mariana Islands
- American Samoa
- Midway Islands
Health Risks Of Daylight Savings Time
Not only those at cardiac risk should be concerned with the health impact of daylight savings as circadian rhythm shift impacts those of all ages, across populations.
In addition to the myocardial infarction studies researchers have examined the health effects of shifts in daylight time on the following:
- Depression
- Suicide Rates
- Thinking Abilities
- Emotional Stability
- Stress
- Immune System Compromise
- Hypertension
- Increases In Tremor
- Increases In Slurring Of Speech
- Decreases In Motor Skill Reaction Times
- Increases In Motor Vehicle Accidents
The need for vigilance in maintaining sleep cycles and attempting to decrease general stress levels (during the weeks prior to and immediately after the change of the clock) surfaces repeatedly in the results of these studies and should be recommended for all.
Sources:
New England Journal of Medicine 2008 Oct 30;359(18):1966-8
Sleepdeprivation.com
Science Daily
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