Daylight Savings Time Increases Heart Attack Risk !
Daylight Savings Time – March 8th 2009
With the end of the winter rapidly approaching, we all look forward to lighter evenings, and the additional daylight that the start of Daylight Savings Time, which begins in the United States on March 8th 2009, brings. Around the world an additional 1.5 billion people experience the same seasonal time adjustment each year.
However, a recent scientific study conducted in Sweden, based on nearly twenty years of heart attack data from 1987 to 2006, indicates that when the clocks ‘spring forward’ each year, this increases the risk of heart attack for many of us.
The research was carried out by the Karolinska Institute in Stockholm, Sweden and the results were then published in the New England Journal of Medicine. These show that there is an amazing five percent increase in the heart attack statistics in the week after Daylight Savings Time begins.
Sleep Deprivation
The theory for this increase is that during the week after the time changes, most people suffer from sleep deprivation. This is compounded by the effect that a sudden time change has on the body’s sleeping patterns and daily biological rhythms.
With this in mind, you may expect a corresponding reduction in the number of heart attacks suffered during the weeks when the clocks ‘fall back’ in the autumn. However, this was not found to be the case, as the researchers discovered that a reduction in heart attacks also of five percent, only occurred on the first day following the end of daylight savings time.
DST results in reduction of sleep quality and duration
Many people find the bi-annual shift in time zones difficult to adjust to, and suffer a reduction in sleep quality and sleep duration, similar to that experienced with jet lag, only semi-permanent. There is a growing volume of evidence that suggests that this may have detrimental effects on our cardiovascular health.
However in the spring, the time change usually results in an hour of missed sleep, and also disrupts the body’s biological rhythms. Contrast this with the fall, when the end of Daylight savings Time combines a biological disruption, with an opportunity to GAIN some sleep, and this may counter the negative effects of the transition.
Monday most dangerous day of the week for heart attacks
It is also interesting to note that Monday is the day of the week that has been proven to be the most dangerous day of the week, and the most likely for suffering from a heart attack. This is most likely to be a combination of two factors – during Friday and Saturday nights most people tend to go to sleep later, and get up later the following morning. However this means that often they will go to sleep later on Sunday as well, but have to rise earlier on the Monday morning to go to work. This causes them to suffer from sleep deprivation. This is combined on Monday morning with a sudden increase in activity and stress related to the week ahead. This is made even worse during the week of the Daylight Savings Time change, and may account for the statistical increase in the heart attack rate.
Heart Risk from Lack of Sleep
If you regularly sleep for less than seven and a half hours per night, you may be putting your heart health at risk, especially if you already suffer from high blood pressure, according to a Japanese sleep study published in the jounal ‘Archives of Internal Medicine’ by Doctor Kazuo Eguchi from Jichi Medical University in Tochigi, Japan.
20 Million People in the UK get less sleep than they need
Sleep enables the physiological and psycholigical restoration and repair of the body. Increasingly stressful modern living, longer commuting and working hours, and all-night shopping and entertainment have all contributed to a worldwide trend towards shorter nights sleep than ever before. Although the average for the United Kingdom is around seven hours, a third of the population – 20 million people – regularly only manage to grab 5 hours sleep or less.
Lack of sleep increases risk of heart disease
However, this lack of sleep may be putting us at increased risk of heart disease, heart attack and stroke as the scientists have discovered that having less than seven and a half hours sleep per night increases the risk factor for heart attack and stroke by up to four times.
The sleep study involved a total of 1255 Japanese patients who were suffering from hypertension, over a period of four years. The patients were aged between 33 and 97 years old, with an average ago of 70. It was discovered that those who had insufficient sleep had a 68 percent increased risk of heart attack, stroke or death from cardiac arrest, with 99 incidents occurring during the study period.
High Blood Pressure and Sleep Deprivation increases risk of cardiovascular problems by 400 percent
The researchers also carried out extensive monitoring of the patients’ blood pressure changes as part of the reseach, and discovered that a relatively small number – twenty of the sleep deprived participants, failed to experience the normal overnight reduction in blood pressure whilst asleep. This smaller subset of the study group were found to be at four times greater risk of cardiovascular problems.
Doctor Eguchi’s team looking for a reason for the sleep study’s findings, believe that a lack of sleep results in greater activity of the nervous system, which also occurs when a persons blood pressure does not fall during the night. This combination in hypertensive patients may cause increased stress of the cardiovascular system, and account for the increased heart disease statistics. It recommends that doctors caring for patients with high blood pressure should investigate and monitor their sleeping patterns more carefully.
It should be noted however, that this study involved patients whose average age was 70 years old, and the results may not necessarily apply to younger people, or those who do not already suffer from high blood pressure.
Chronic deprivation of sleep can also be linked to a number of different health problems, including diabetes and obesity, and there is a link betweeen childhood sleep deprivation and future obesity in adulthood.
What about getting too much sleep ?
Another sleep study carried out at Warwick University in the United Kingdom in 2007 has shown that not only is too little sleep bad for your health, but sleeping for too long can also have harmful effects on your health. This study, carried out by Professor Francesco Cappuccio from the Warwick University Medical School involved over 10,000 government workers in the United Kingdom over a period of 11 – 17 years, and concluded that the optimum amount of sleep is 7 hours per night. However it also uncovered the startling fact that those whose sleep is excessive – more than 8 hours per night, doubled their risk of dying. In these cases however, the cause of death was not primariliy due to heart diseases.