A number of middle-aged and older adults customarily take a nap during the day and consider it a healthy way to recharge their batteries. However, a new study has found a relationship between daytime napping and mortality in this age group. It also found an association between daytime napping and respiratory disease in younger individuals. The findings were published in the May edition of the American Journal of Epidemiology by researchers at the University of Cambridge in the United Kingdom.
The study authors note that in recent years, studies have found a link between sleeping habits and mortality; however, most of these studies focused on the duration of nighttime sleep. Thus, limited information is available. They note that daytime napping, has been suggested to be an early sign or risk indicator of a range of health problems; however, currently, the relationship between daytime napping and mortality risk is unclear. In addition, most studies are from the Mediterranean area where many individuals customarily take a siesta. Therefore, the conducted a study to evaluate daytime napping and mortality among a British population.
The researchers investigated the relationships between daytime napping and all-cause or cause-specific mortality in the European Prospective Investigation Into Cancer (EPIC)-Norfolk study, which comprised a British population. The study group included 16,374 men and women who answered questions on napping habits between 1998 and 2000. During the 13 year follow-up period, 3,251 individuals died. The investigators found that daytime napping was associated with an increased risk of all-cause mortality (for napping less than one hour per day on average; 1.14-fold increased risk); for napping one hour or longer per day on average, the risk was 1.32-fold. The increased risk was independent of age, sex, social class, educational level, marital status, employment status, body mass index (BMI), physical activity level, smoking status, alcohol intake, depression, self-reported general health, use of hypnotic drugs or other medications, time spent in bed at night, and presence of preexisting health conditions.
The investigators found that the associating between daytime napping and mortality was greater for death from respiratory diseases (for napping less than one hour; 1.40-fold increased risk); for napping one hour or more, the risk was 2.56-fold greater, 95% confidence interval: 1.34, 4.86). Interestingly, the risk of death from respiratory diseases was higher in individuals 65 years of age or younger.
The investigators concluded that excessive daytime napping might be a useful indicator of an underlying health risk, particularly from respiratory problems. Furthermore, the risk of death from respiratory problems was higher in individuals 65 years of age or younger. They recommended that further research should be conducted to clarify their findings.