Daily? Never? For me, and I'm guessing for many of you, the answer is somewhere in between.
Researchers posed that question to tens of thousands of study participants to investigate whether tiredness has a genetic basis. They found that genes play a small but significant role in overall fatigue.
The multi-institutional team of researchers analyzed genetic data from the UK Biobank for 108,976 individuals who reported whether they had felt tired in the last two weeks. The participants selected four possible answers, ranging from “not at all” to “nearly every day;" most answered either “not at all” or “several days.”
The researchers found that genetic factors account for about 8 percent of the participants’ differences in self-reported tiredness, as outlined in a paper recently published in Molecular Psychiatry. This implies that tiredness is largely due to other factors, such as not getting enough sleep.
Some inherent factors such as personality traits or poor health can contribute, however. By averaging tiredness across a large sample and performing a genomic-wide association study, the researchers identified genetic links between tiredness and inherent factors — using the UK Biobank’s data on the participants’ physical health, mental health, personality and cognitive functioning.
They found that an individual’s genetic predisposition to some physical and mental illnesses — not just the presence of these illnesses — was associated with feeling tired. For instance, people who were genetically prone to Type 2 diabetes were also prone to tiredness, even if they did not have diabetes.
The authors summarized that tiredness is a “partly heritable, heterogeneous and complex phenomenon," which requires further research to fully understand. However, they indicate that most of the differences in tiredness can be attributed to external factors such as the lack of sleep.