Next, Wenzler looked at the results of a cognitive function test over a 10-year period to see how the scores differed at the end of the decade.
Her conclusion was that evening people saw faster cognitive decline. But every night owl may not have the same risk.
“We found that 25% of the effect was due to lower sleep quality and smoking,” Wenzler tells Fortune. “So, having a healthy lifestyle could lower the negative effect of having a late chronotype a bit.”
She says that, for this study, she only looked into the executive function of the brain, so more research is needed into how chronotype affects memory, language, and other cognitive aspects.
But if work and other factors won’t allow you to stay up till 2 a.m. and sleep in until 10 a.m., could you push yourself to become an early bird?
“Some studies showed that intensive intervention could help change your chronotype… but only by a few hours,” Wenzler says. “But forcing yourself to get up early every day while you are an extreme evening person will not make you a morning person. In these cases, it might be best to adapt your life, as much as possible, to your chronotype.”
Walker also noted that only slight shifts are really possible, and that the ongoing, disciplined interventions that are required to truly change chronotypes are “just not tenable,” he said. “Let night owls sleep as they were biologically designed. At least, that’s how I feel on the basis of the science and medicine of the data.”
So, is the cognitive health of night owls just simply doomed?
“If these individuals are doomed is hard to say, as we only had a follow-up of 10 years,” says Wenzler, explaining that the true long-term effects—particularly whether or not night owls are more likely to develop dementia—need further investigation.
“Faster cognitive decline in middle age does not necessarily mean a higher risk of dementia,” she said in the news release. “With our research, we hope to find out more about this. This will ultimately help us to be able to give people informed advice on how to try to prevent dementia.”
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