Keep naps under 30 minutes—no longer than an hour. If you regularly need a one- or two-hour nap to get through the day, it’s time to see a doctor

Free. Just set an alarm before you nap; it requires very little willpower.

One umbrella meta-analysis compiled data from 16 separate meta-analyses covering 244 health outcomes. An umbrella meta-analysis essentially aggregates findings from multiple existing meta-analyses. Its conclusions: individuals who nap for less than 60 minutes show no rise in overall mortality or chronic disease risk, and experience the greatest improvement in cognitive function (SMD 0.69, 95% CI 0.37–1.00—a reliable range). Naps lasting 20–30 minutes provide the biggest boost to physical performance (SMD 0.99, 95% CI 0.67–1.31). On the other hand, people who nap for over an hour face a roughly 30% higher risk of coronary heart disease, and about a 20% higher risk of diabetes and obesity. Another study used wrist-worn monitors to objectively measure naps in 1,338 adults aged 56 and older, rather than relying on self-reported questionnaires. After up to 19 years of follow-up, 926 participants had died. For every extra hour of napping, mortality risk rose by about 13% (HR 1.13, 95% CI 1.04–1.23). Each additional daily nap added roughly 7% to mortality risk (HR 1.07, 95% CI 1.02–1.13). People who napped in the morning faced a roughly 30% higher risk compared to those who napped earlier in the afternoon (HR 1.30, 95% CI 1.03–1.64).

Du P, Li J, Hua Z, 等 (2026). Multiple Health Outcomes of Daytime Napping: A Comprehensive Umbrella Review. Public Health Reviews. https://doi.org/10.3389/phrs.2026.1609013；Gao C, Cai R, Zheng X, 等 (2026). Objectively Measured Daytime Napping Patterns and All-Cause Mortality in Older Adults. JAMA Network Open. https://doi.org/10.1001/jamanetworkopen.2026.7938；Dashti HS 等 (2021). Genetic determinants of daytime napping and effects on cardiometabolic health. Nature Communications. https://doi.org/10.1038/s41467-020-20585-3

Controversial. The two items above are studies that only record data without random assignment. People who take long naps are already more likely to have sleep apnea, anemia, hypothyroidism, depression, or other chronic diseases. Therefore, it is unclear how much of the "longer sleep leads to more deaths" is caused by the nap itself. Causal inference using genetics (Mendelian randomization, 453,000 people plus 541,000 people) supports only one thing: the more frequent the naps, the slightly higher the blood pressure and waist circumference. It did not find a causal effect of napping on coronary heart disease and diabetes. Therefore, do not treat "sleeping less during naps" as a means to reduce mortality. The part about "checking for causes" is the author's suggestion and belongs to Class C: if you are so sleepy during the day that you must sleep for a long time, first check your nighttime sleep; for snoring and gasping for air during sleep, check for sleep apnea, and then check complete blood counts and thyroid function. For how short naps can refresh you, see Section 3, Item 11 (sleep for 10 minutes if sleepy in the afternoon). For how long to sleep at night, see this section, Item 13 (sleep 7 hours every night). For how to check and treat snoring and gasping, see Section 3, Item 27 (sleep apnea).