Have you noticed that you’re often irritable, confused, or even jittery? The answer could be fluctuating blood sugar levels.
To test that blood sugar fluctuations caused irritability, researchers at Ohio State University tracked the nightly blood sugar levels of 107 married couples for 21 days. The team also gave participants a way to express anger: voo-doo dolls representing their spouses and a personal stack of 51 pins.
In a second test, spouses were put in separate rooms and told that they were competing against each other in a computer game. In fact, each spouse was pre-set to lose 13 of 25 trials in a random assortment. The spouse that won had the opportunity to blast his or her partner with a loud ugly sound — or opt for “no noise.” The noise was a mixture of fingernails scratching on a chalkboard, dentist drills, ambulance sirens. Winners also got to choose from one to 10 noise levels, up to the volume of a fire alarm, and whether the sound would last along a spectrum from half a second to 5 seconds — a lab measure of aggression that has been used for decades. Spouses also had the option of delivering no punishing noise if they won. When they were on the receiving end, a computer delivered a random blast.
Guess what? Participants with below-normal glucose levels in the previous three weeks chose to punish their spouses with louder sounds, and for longer.
Other studies have focused on the so-called “hangar” effect. People who drank sweet lemonade were less aggressive in a similar computer test of aggression. And people with diabetes, who may have fluctuating sugar levels, emerged as less forgiving in another study.
In “Willpower: Rediscovering the Greatest Human Strength,” Florida State University psychologist Roy Baumeister, PhD, and his co-author John Tierney from The New York Times made the point simple: "No glucose, no willpower,"
Tamping down anger requires will-power directed towards self-control.
However these experiments don’t nail down the underlying idea, which remains controversial, that there is a direct relationship between your blood sugar level at any one point in time and your capacity for self-control. The answer isn’t to eat a candy bar before important discussions. You can build up your self-control with good habits, over time, Baumeister observes. Making your bed every day is a start.
But if you know you tend to get irritable, perhaps later in the day after missing meals, don’t let your health damage your relationships. Regular exercise can protect you against developing blood sugar problems. Balanced snacks that contain some protein are a good bet during the day — especially nuts. Keep them at the office if you find you are missing lunch and getting irritable around co-workers and demanding bosses.
How would you feel if you took that noise test and found yourself giving your life partner a loud long blast?
September 11, 2015
Christopher Nystuen, MD, MBA