Sometimes my reserves of willpower feel abundant. That last piece of chocolate cake? Save it for the husband. Other times I turn into a slavering Homer Simpson. The cake is so enticing that in a red-hot minute it’s down the hatch.
A new review article by researchers from Clemson University suggests that not just impulsive eating but a lack self-control in general may be attributable to poor sleep habits and poor sleep. This claim will resonate with many insomnia sufferers, so here’s a summary of the authors’ key points.
Decisions, Decisions, Decisions
Decision-making is daily part of life: whether to tackle a difficult task or postpone it, whether to vent anger or try to chill out, whether to exercise, whether to have a third drink, whether to stay up late watching a movie. The choices we make depend in part on our reserves of self-control. Among other things, self-control enables us to resist “pleasurable impulses to better meet long-term goals.” It also helps in the regulation of social behaviors.
Our capacity for self-control is limited. Failures may occur mainly due to a depletion of physiological resources. After hewing to the straight and narrow and holding impulsive behaviors in check for a while, so the thinking goes, our internal resources are depleted, “much as a muscle becomes fatigued following physical exertion.” To date, research has focused on levels of glucose—the body’s main source of energy—as being the main indicator of available internal resources. When blood glucose levels are low, the body tends to conserve (rather than utilize) glucose, in turn reducing energy and our capacity to exert self-control.
On the other hand, the loss of self-control may be attributable mainly to psychological processes and motivation. Belief in willpower and personal motivation—I CAN resist that chocolate cake and I WILL resist it to look good at the beach—enables people to exert self-control at times when they’re faced with the dilemma of whether to trade short-term pleasure for long-term gain. It’s likely that both psychological and physiological processes underlie the loss of self-control, the authors state.
A Relationship Between Self-Control and Sleep
Quite a bit of research shows that sleep deprivation and insomnia have negative effects on health and quality of life. There’s much less research on the question of how inadequate sleep affects self-control, but investigators in a few studies have found that sleep deprivation decreased self-control and increased interpersonal hostility. Here’s what the authors suggest may be behind poor sleep’s effects on self-control:
- The circadian system influences the timing of sleep, hunger, and the metabolizing of glucose. Sleep deprivation alters circadian rhythms and has a negative effect on the ability to metabolize glucose, processes which could impair self-control.
- Irregular bedtimes and being chronically short on sleep are known to interfere with the restorative functions sleep performs, such as the healing of damaged tissue and the stabilizing of mood. This too could lead to a loss of self-control, which in turn could perpetuate poor sleep habits.
- Neuroimaging studies show that sleep deprivation decreases activity in the prefrontal cortex, a brain area important in making decisions and moderating social behavior. These higher-level prefrontal regions, which normally put the brakes on drives and emotional responses generated by lower subcortical regions, may not be able to function optimally, which could also result in a loss of self-control.
Poor sleep whatever its provenance (sleep apnea, restless legs syndrome, or insomnia) may increase your vulnerability to all kinds of injudicious behaviors, from overeating and binge drinking to overspending and yelling at the boss. When impulse control is in short supply, look for ways to improve your sleep.
In what areas is it hard for you to maintain self-control?