Resource post for November: time change, sleep and your heart

Have you reset your clocks? Ready for the time transition? Depending on the season, we are moving back and forth in time. We “spring forward” in the spring and “fall backwards” in the autumn. The North Americans call it Daylight Saving Time or DST for short and Standard time, respectively. In Europe, we can it “summer time” and “winter time.”

How does time transition affect our health?

According to this latest study published in the New England Journal of Medicine, these transitions in time are linked to higher incidence of acute heart attacks. The Swedish study shows that the number of heart attacks increases significantly during the first 3 weekdays after the transition to daylight saving time (DST) in springtime. The effects of turning back the time in autumn is not so strong but still evident during the first weekday. Furthermore, there are some differences observed in the time transition effects which are dependent on gender and age.

The effect of the spring transition to daylight saving time on the incidence of acute myocardial infarction was somewhat more pronounced in women than in men, and the autumn effect was more pronounced in men than in women… The effects of transitions were consistently more pronounced for people under 65 years of age than for those 65 years of age or older.

Time change interferes with our biological rhythm and our daily routine especially our sleep. The most plausible explanation for the increase in heart attacks is sleep deprivation, which can badly affect cardiovascular health.

Because of its dependence of daylight hours, DST has also an effect on health conditions such as depression, vitamin D insufficiency, and night blindness.

 Who are most likely to be affected?

As the abovementioned study above suggests, those with heart problems and but also adults below 65 are more likely to feel the adverse effects of time change. Babies and little children will also feel it and get restless, adding to the woes of the poor parents.

Depending on each individual, the effects can last between 1 day and two weeks!

In addition, the severity and the duration of the effect vary from person to person. In general, however, “owl types” tend to suffer more at springtime.

Night owls” or “evening types” are people who have a natural tendency to stay up later at night. This puts them at risk for delayed sleep phase disorder, which occurs when their usual bedtime and wake time are much later than the social norms.

Since night owls have a hard time falling asleep when they go to bed early, they may be unable to compensate for the time change. As a result they may go to bed even later than normal, depriving themselves of needed sleep.

Those who are “morning types” among us however, will experience more problems this autumn (November 2) when we go back to Standard Time

How can we minimize the effect of time change?

The American Academy on Sleep Medicine (AASM) gives us the following tips to counteract the effects of time change:

• Begin to re-adjust your sleep schedule a few days prior to the time change by going to bed an hour earlier.
• Re-adjust your eating schedule by having dinner an hour earlier.
• Be careful when driving or operating machinery on the day of the time change.
• Avoid napping, particularly before bedtime.
• Avoid caffeine in the morning to wake you up and alcohol at night to help you go to sleep.
• Keep a light schedule on the Monday after the time change. This involves minimizing driving and avoiding strenuous physical activities.  
• Eat properly, stay well hydrated and remain physically active.

 Why change time at all?

If it is bad for our health, then why do it?

Switching to DST is something we have to put up with because we are living in higher altitudes and have therefore varying day lengths depending on the season. People living close to the equator don’t need to bother with this.

Adjustment for DST in spring aims to optimally use the daylight hours, with the following results:

• It makes us start work earlier in the morning when the sun rises early, and then leave us enough daylight hours in the evening for outdoor leisure activities.
• It reduces energy consumption because we tend to use less indoor lighting.
• Business benefits from DST because it encourages people to shop longer in the evenings.
• It also aims to reduce traffic accidents and crime that usually tend to happen in the dark hours.

However, it does not benefit everybody, e.g. people who work in shifts (hospital staff, for example), those who frequently have to cross time zones (airline personnel, for example). The shift in time can create havoc with time-dependent machines and computer systems. International businesses get disrupted. For years, the time change on the two sides of the Atlantic happened on the same weekend – the last Sunday of March for DST and the last Sunday of October for going back to standard time. This has changed since 2007. In the US and Canada, it now happens on the second Sunday of March and the first Sunday of November. This asynchrony even complicates things and brings confusion to people working on intercontinental projects.