Whether it’s a student finishing that term paper at two in the morning, a resident working a 20 hour shift or an office administrator with a newborn at home, we’re all getting less sleep. A recent Gallup poll showed that 40 percent of Americans aren’t getting enough.
This isn’t a benign problem. Lack of sleep has been linked with a veritable cornucopia of potential health problems (diabetes, obesity, memory issues, even cancer).
The cumulative effect of not getting enough sleep is known as sleep debt, and although we try to make up that debt on the weekends or days off by getting as much sleep as we can, is that enough?
We asked David Gozal, MD,the Herbert T. Abelson Professor and chairman of pediatrics at the University of Chicago, a pioneer in the study of childhood sleep problems and the connections between sleep disorders and neurobehavioral, cardiovascular and metabolic disease:
Can you ever repay your sleep debt?
David Gozal: We don’t know.If a person goes without sleep for just one night and tries to replace that lost sleep – to repay their full sleep debt in just a day or two, most likely they will be able to regain normal function.
But getting extra sleep does not immediately restore all systems. The neural activity, the metabolic activity, these take much longer to recover, even if you sleep more than you think you need. Recovery is not so simple.
If people can’t quickly recover from a brief but acute loss of sleep, what happens when people habitually lose sleep, now a common practice? A growing list of studies has connected chronic partial sleep deprivation not just to cognitive deficits but also to changes in hormone secretion, metabolism, weight gain, delayed immune response and other deficits.
We are finding more and more connections. My lab, working with mice, recently demonstrated a link between disrupted sleep and cancer progression. Another research team found connections between sleep loss and trouble eliminating toxins. Another team, working with fruit flies, showed that sleep loss could hamper courtship and sexual behavior.
For many species, reproductive behaviors fit into a narrow temporal window. If you fail to engage in the appropriate behavior at the right time, you may lose your opportunity. It’s a no-way street; it’s gone.
My team has also recently shown that under certain conditions, disturbed sleep can alter gene expression. The offspring of female mice who have fragmented sleep late in pregnancy tend to gain weight months later, during the mouse equivalent of middle age.
Evolution has provided us with many mechanisms to counter the effects of sleep loss. The fact that we have those mechanisms is good news but it’s also an indication that sleep loss must be a serious problem if we need so many response systems.
I would opt for caution. Rather than take on the risk, or assume that you can counteract all the sleep losses you incur, a little bit of prevention may be wise. Treat your sleep like a bank account. Avoid overdrafts and your credit history will be perfect. If you accumulate debt, there will be compounded interest and an uphill battle to recover. There may be an enduring little red flag marking your ‘bad sleep’ credit history. You might not get a loan when you need it.