What is Shift Work?
Shift work is an employment practice designed to make use of, or provide service across, all 24 hours of the clock each day of the week
EFFECTS OF SHIFT WORK
Everyone has a “biological clock,” a 24-hour schedule on which the body functions. This schedule is known as the circadian cycle. This cycle is introduced, maintained and reinforced in every person’s life. If this cycle is disturbed for just one day, it will take:
Five days for urinary electrolytes to adjust
Eight days for the heart rate to adjust
Six days for body temperature to adjust
Shift Work and Heart Attack
Scientists have known for a while that shift work upsets the body's natural body clock (circadian rhythm) and work-life balance
What is heart attack?
If the heart muscle does not have enough blood (and consequently oxygen) it dies and a heart attack occurs. Another name for a heart attack is myocardial infarction, cardiac infarction and coronary thrombosis. According to medical dictionary, a heart attack is "infarction of a segment of heart muscle, usually due to occlusion of a coronary artery". (Infarction = the process whereby an area of dead tissue is caused by a loss of blood supply).
A heart attack usually happens when a blood clot develops in one of the blood vessels that lead to the heart muscle (coronary arteries). The clot, if it is big enough, can stop the supply of blood to the heart. Blood supply to the heart can also be undermined if the artery suddenly narrows, as in a spasm.
What are the symptoms of a heart attack?
Chest discomfort, mild pain
Coughing
Crushing chest pain
Dizziness
Dyspnea (shortness of breath)
Face seems gray
A feeling of terror that your life is coming to its end
Feeling really awful (general feeling)
Nausea
Restlessness
The person is clammy and sweaty
Vomiting
What are causes of a heart attack?
Age –
Angina - angina is an illness where not enough oxygen is reaching the patient's heart
Blood cholesterol levels
Diabetes
Diet
Genes
Heart surgery
Hypertension (high blood pressure
Obesity, overweight
Physical inactivity
Previous heart attack
Smoking
What are the treatments for a heart attack?
The faster the heart attack patient can be treated, the more successful his/her treatment will be
Treatment during a heart attack
CPR (cardio-pulmonary resuscitation)
300mg of Aspirin
Hrombolytics
Painkillers
New scary study- Shift Work Tied To Higher Risk For Heart Attack, Stroke
An analysis that reviews studies covering over two million people finds shift work is associated with a higher risk for vascular events, such as heart attack and ischaemic stroke. The study is the largest examination of shift work and vascular risk to date. The researchers, from Canada and Norway, write about their findings in a paper published online in the BMJ on Thursday. They report that compared to regular daytime workers, shift workers had a 24% higher risk for coronary events, a 23% higher risk for heart attack, and a 5% higher risk for stroke.
Night shift workers had the highest risk for coronary events (41%). However, shift work was not linked to a higher risk of death (from any cause).
Why the Study?
Scientists have known for a while that shift work upsets the body's natural body clock (circadian rhythm) and work-life balance, and a number of studies have linked it to health problems, such as increased risk of high blood pressure and high cholesterol. A link with diabetes is also well-established, for instance, a Harvard-led study reported that rotating shift work is linked to higher risk for type 2 diabetes.And the link with cancer has already made a mark in the politics of occupational health since 38 Danish female night shift workers in 2008 were compensated after their breast cancer was officially recognized as an occupational illness. But, the link between shift work and vascular disease is controversial. The authors propose one reason could be the varying methods, populations and definitions of shift work and coronary events that previous studies have used. They also suggest previous analyses are now outdated: they "did not use validated tools for assessing studies, did not capture all available data, and did not apply quantitative techniques to compute summary risk estimates," they write.
What they found?
For their study, the international team, led by Daniel G Hackam, associate professor in the Department of Epidemiology and Biostatistics at Western University in Canada, pooled and analyzed the results of 34 studies covering 2,011,935 people and compared shift workers to regular daytime workers or the general population.
They defined shift working as working patterns that differed from regular daytime working (9 am to 5 pm), including evening shifts, irregular or unspecified shifts, mixed schedules, night shifts and rotating shifts.
Of the more than 2 million participants, 17,357 experienced some kind of coronary event, 6,598 had heart attacks (myocardial infarction), and 1,854 had ischaemic strokes. An ischaemic stroke is caused by a lack of blood supply in the brain.
The analysis showed all these vascular events were significantly more common among shift workers than other people.
The researchers found that:
1. Shift work was associated with myocardial infarction (risk ratio 1.23, 95% confidence interval 1.15 to 1.31; I2=0) and ischaemic stroke (1.05, 1.01 to 1.09; I2=0). Coronary events were also increased (risk ratio 1.24, 1.10 to 1.39), albeit with significant heterogeneity across studies (I2=85%)."
By "significant heterogeneity" the researchers refer to the fact that there was a certain lack of consistency in research methods, assumptions, sampling criteria and definitions across the 34 studies they analyzed.
2. When they examined the possible sources of this lack of consistency in study methods, they found that "presence or absence of adjustment for smoking and socioeconomic status" was not one of them.
3. They also found that although the risk for vascular events was higher among shift workers, the results show they were at no higher risk of death from any cause.
Implications
The researchers say that although the relative risks they calculated are modest, because of the high frequency of shift work in the general population, the implications for public health are not insignificant.
For instance, if you applied these risks to Canada, where during 2008-09, nearly a third of workers were on shifts, then 7% of heart attacks, 7.3% of all coronary events, and 1.6% of ischaemic strokes could be due to shift working.
The findings should impact public policy and occupational medicine, say the researchers.
For example, shift workers could be educated about how to spot early signs of heart problems, and screening programmes could help identify and treat risk factors like high blood pressure and cholesterol in shift workers. The researchers call for further studies to find out which groups of shift workers are likely to be the most affected by these findings, and how overall vascular health is affected by changes in shift patterns.
(Source-BMJ)
SHIFT WORK: ALTERNATIVES
There are basically three major alternatives for shift work:
1) Rapid rotation;
2) Dedicated (permanent) shifts
3) Slow rotation
1. Rapid rotation
Perhaps the most disruptive type of shift work is rapid rotation. This protocol is common in police work, where an officer must change from afternoon to day to night shift in the space of one week. In terms of disturbing one’s “biological clock,” rapid rotation is devastating. Past experiments by Dr. C.F. Ehret have demonstrated that rapid rotation caused such high disruption in laboratory animals that no Circadian rhythm could be detected. Body temperature and blood chemistry of these animals were in a constant state of flux. Dr. Ehret concluded that individuals who must face critical decisions (such as police officers) should not work rapid rotation shifts. Their performance levels are seriously affected especially in the early morning hours.
2. Dedicated (permanent) shifts
Permanent shifts are effective for reducing the problems of shift work. Such shifts eliminated the major cause of disruption: change. There is increasing evidence that fixed shift systems are more cost-effective than other protocols. Recently, many departments are moving to extended fixed shifts consisting of either 10 or 12 hour shifts. Officers appear to like these extended hour shifts because they allow for more time off duty. Research in several police departments indicated a dramatic decrease in sick leave and an increase in productivity as a direct result of permanent shifts. Other departments conclude that their permanent shift program makes it easier to plan schedules.
Of course, the fixed shift approach is not perfect. Twelve hour shifts, for example, can increase the risk of fatigue, especially on the midnight tour. Such shifts may also cause a morale problem, especially among younger officers who are involuntarily assigned to night shifts. Many officers who work nights permanently tend to deprive themselves of sleep and “burn both ends of the candle.” This could lead to individual health problems, as well as poor work performance.
3. Slow rotation
A third type of shift protocol involves slow rotation. Slow rotation refers to changing shifts over an extended period of time. Dr. Ehret suggested that slow rotation is better than rapid rotation—better on the premise that it causes the least amount of disruption among officers who must change shifts. Ideally, Dr. Ehret states, slow rotation is the logical choice when permanent shifts are impossible. He recommends that officers not be required to change shifts for at least 4-5 weeks at a time. This allows for minimal disruption of the circadian cycle.
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