Summer Sleep: Why You Sleep Worse When It's Hot and What to Do About It
The onset of sleep is directly tied to a drop in core body temperature of between 1 and 2 degrees F. In hot environments, that process of central temperature decline meets resistance because when the bedroom temperature is high, the body has difficulty dissipating heat into an external environment that is already warm. That explains why people in hot climates without temperature control take longer to fall asleep, experience greater sleep fragmentation, and spend less time in the deep sleep and REM sleep phases — the most restorative of all.
The Ideal Bedroom Temperature and Summer Bedding
The ideal bedroom temperature for sleep is between 65 and 68 degrees F. That temperature is significantly lower than what feels comfortable when awake, but the body in deep sleep maintains a core temperature significantly lower than during wakefulness, and a cool environment facilitates that drop. Bamboo sheets have heat-dissipation properties significantly better than traditional cotton and can make a real difference in sleep quality during the warmer months. Available for between $40 and $100 per set. The summer blanket should be as light as possible: an extra sheet of thin cotton provides sufficient coverage without excess heat.
The Cold Shower Paradox: Why It Doesn't Work the Way You Think
When the body is exposed to cold water, it reactivates its heat-conservation mechanisms as a reflex response. Once out of the cold water, that mechanism produces a rise in core body temperature — exactly the opposite of what is needed to initiate sleep. The strategy that does work is a warm shower taken between 30 and 90 minutes before bed. Warm water dilates the peripheral blood vessels, facilitating the dissipation of heat from the body's core to the environment. Upon stepping out of the warm shower, core body temperature drops actively, making it easier to fall asleep.
Alcohol and Sleep Schedules in Summer
Alcohol does effectively ease the onset of sleep at the beginning of the night. The problem is what it does during the rest of the night: it suppresses REM sleep during the first hours of its metabolism, produces night sweats that raise body temperature, and activates the sympathetic nervous system, resulting in light, restless sleep. A consistent sleep schedule is especially important in summer: the social jet lag of going to bed at midnight on weekdays and at 2 a.m. on weekends desynchronizes the circadian rhythm heading into the following week. Keeping a consistent wake time produces better sleep quality than any number of recovery sleep hours on Sundays.
Summer Sleep as an Investment in Everything Else
Mood, concentration, emotional regulation, the immune system, metabolism, skin, performance at work and during exercise — all of those aspects of life that one wants in good shape during summer depend critically on the quality of nightly sleep. The time spent creating the conditions for quality summer sleep — the right bedroom temperature, the right sheets, the consistent schedule, the warm shower before bed — is the most efficient investment available for making all the other hours of the day higher quality. A summer well slept is not just a summer better rested. It is a summer better lived.