What we have just done should actually have come with a health warning, for scientists in the USA have just proved that remembering something unpleasant from your past can increase your risk of a heart attack or stroke for up to 40 minutes. 

Scientists have found that the emotion of anger can impair the function of blood vessels, restricting blood flow in a way that could lead to a serious medical incident. 

Researchers from Columbia University Irving Medical Center in New York analysed the cells lining blood vessels to look for signs of “impaired blood vessel dilation, increased cell injury and reduced cell-repair capacity”. 

They recruited 280 participants and randomly assigned them to four eight-minute studies. One asked them to recall a personal memory that made them angry, another asked them to remember a moment of anxiety, one asked them to read a series of depressing sentences designed to evoke a feeling of sadness and the fourth asked them to count repeatedly to 100 as an emotionally neutral task. 

Measurements of their blood pressure and blood vessel dilation were taken after three minutes and again at 40, 70 and 100 minutes after completion of the task, and blood samples were taken to assess cell health. 

They found: “Tasks that recalled past events causing anger led to an impairment in blood vessel dilation, from zero to 40 minutes after the task. The impairment was no longer present after the 40-minute mark. 

“There were no statistically significant changes to participants’ blood vessel linings at any time points after experiencing the anxiety and sadness emotional tasks.” 

Interestingly – and significantly for you – this risk isn’t limited to older people, who are usually more susceptible to heart attacks and strokes. The average age of the participants in the trial was just 26, so not that much older than the oldest of you here, even without the U6.  

Even though he wouldn’t have known the science behind it, William Shakespeare understood the futility of dwelling on – or worse, reliving – unpleasant experiences from our past. In his Sonnet 30 (in which he coins the famous phrase “remembrance of things past”: A level French students – which French novelist does this phrase relate to?), Shakespeare likens going over negative past experiences as being like paying a debt twice over: both pointless and painful, and only damaging to the person doing the paying.  

The biblical writers too understood well the damage that dwelling on the past can do. The prophet Isaiah writes “No need to remember past events, no need to think about what was done before,” and St Paul in his Letter to the Philippians talks about “forgetting all that lies behind me, and straining forward to what lies in front.” 

And now we have the science to back up the message that dwelling on the past is unhelpful; in fact, it can make you ill. Move on; cast off the past and look forward. To quote one more great cultural icon, the movie Frozen, let it go!