Coffee consumption is widely recognized for a variety of positive health benefits. These include a reduced risk for certain cancers, better liver health, and less risk of cardiovascular disease; sharper mental clarity and slower cognitive decline; and even lower mortality in the face of disease (Pourshahidi, Navarini, Petracco, & Strain, 2016).
Now there's a new reason to drink coffee: It may help your relationship. A new study by Maranges and McNulty is the first to demonstrate a link between couples' sleep deprivation and their romantic relationship satisfaction. Researchers recruited approximately 70 newlywed heterosexual couples, who completed separate surveys every day for a week, each of which assessed their sleep, satisfaction with specific events in different domains of their relationship (e.g., conflict, conversation, sex), and then their global relationship satisfaction.
Evidence clearly indicated that couples were happier in their relationships on the days after they had a better night's sleep. Husbands who slept well also showed a weaker link between negative evaluations of specific relationship events that happened on any particular day and the negativity of their global relationship judgments. In other words, not-so-great moments during a day weren't as predictive of their overall feelings about their relationship. That's a good thing.
How might sleep connect to feelings about one's romantic partner? The authors suggest that we all need self-control, or self-regulatory strength, to help us differentiate between the daily ups and downs (particularly the "downs") and overall relationship satisfaction. We need the mental strength to override negative feelings about a specific event to make a positive judgment about a relationship.
Sleep deprivation may be problematic if it takes a toll on self-regulatory strength. Without this strength, negative judgments tied to something specific that happens (for husbands, at least) can bleed into overall relationship judgments.
Getting more sleep, of course, is the most direct way to replenish sleep deficits. But if that's not available, coffee might help, too.
In a different study, Welsh and colleagues (2014) tested the way caffeine influences the effect of sleep deprivation on self-regulation. They recruited 229 participants, some of whom were sleep deprived, while others had a good night's sleep. Some received the equivalent of a 12-oz cup of coffee and others received a placebo. The researchers then measured participants' ability to exert self-control by resisting unethical social influence.
Findings revealed that sleep deprivation hurt self-regulatory strength, but participants who had caffeine were much better off. In other words, caffeine consumption moderated the deleterious effects of sleep deprivation on self-regulatory strength. People who had caffeine had more self-regulatory strength to override social influence.
If caffeine boosts self-regulatory strength in the face of sleep deprivation, then we have a potential, if temporary, solution to the challenge that not getting enough sleep may cause in romantic relationships. If a lack of sleep lowers the self-regulatory strength we need to make positive global judgments about our relationships, a cup of coffee might be just what the doctor ordered.
Maranges, H. M., & McNulty, J. K. (2017). The rested relationship: Sleep benefits marital evaluations. Journal of Family Psychology, 31, 117-122.
Pourshahidi, L. K., Navarini, L., Petracco, M., & Strain, J. J. (2016). A Comprehensive Overview of the Risks and Benefits of Coffee Consumption. Comprehensive Reviews in Food Science and Food Safety, 15, 671-684.
Welsh, D. T., Ellis, A. P., Christian, M. S., & Mai, K. M. (2014). Building a self-regulatory model of sleep deprivation and deception: The role of caffeine and social influence. Journal of Applied Psychology, 99, 1268-1277.