Can People Sleep Too Much? Effects of Extended Sleep Opportunity on Sleep Duration and Timing.

Elizabeth B Klerman,Charles A Czeisler,Thomas A Wehr,Giuseppe Barbato

doi:10.3389/fphys.2021.792942

Abstract

Many people are concerned about whether they are getting “enough” sleep, and if they can “sleep too much.” These concerns can be approached scientifically using experiments probing long-term (i.e., multi-night) sleep homeostatic processes, since homeostatic processes move the system toward its physiological setpoint (i.e., between “not enough” and “too much”). We analyzed sleep data from two human studies with sleep opportunities much longer than people usually stay in bed (i.e., conditions in which sleep homeostatic responses could be documented): sleep opportunities were 14–16 h per day for 3–28 days. Across the nights of the extended sleep opportunities, total sleep duration, Rapid Eye Movement (REM) sleep duration and non-REM sleep durations decreased and sleep latency increased. Multiple nights were required to reach approximately steady-state values. These results suggest a multi-day homeostatic sleep process responding to self-selected insufficient sleep duration prior to the study. Once steady state-values were reached, there were large night-to-night variations in total sleep time and other sleep metrics. Our results therefore answer these concerns about sleep amount and are important for understanding the basic physiology of sleep and for two sleep-related topics: (i) the inter-individual and intra-individual variability are relevant to understanding “normal” sleep patterns and for people with insomnia and (ii) the multiple nights of sleep required for recovery from insufficient sleep from self-selected sleep loss is important for public health and other efforts for reducing the adverse effects of sleep loss on multiple areas of physiology.

Highlights

Sleep During Extended Sleep Opportunities sleep and multiple adverse effects [e.g., (Scott et al, 2006; Van Cauter et al, 2008; Mullington et al, 2009)]
The time constant and steady-state values from an exponential fit for total sleep time (TST), Non-Rapid Eye Movement (NREM) sleep, and Rapid Eye Movement (REM) sleep were similar in both studies (Table 2); of note, the fit steady-state value for TST was more than 8.5 h
We demonstrate that the average healthy young human can not chronically sleep over 10 h per day: the average sleep duration was 8.6 h over the last 14 nights of the Study 1 protocol

Summary

Introduction

Sleep During Extended Sleep Opportunities sleep and multiple adverse effects [e.g., (Scott et al, 2006; Van Cauter et al, 2008; Mullington et al, 2009)]. Given that individuals may choose to arise from bed for physiological and psychological reasons before their sleep homeostatic drive is fully dissipated, the design of a study of the effects of extended sleep opportunity should ideally include documentation of sleep history, use of substances that may affect sleep or wake, and enforcement of time in bed during the entire scheduled bedrest episode(s) for each participant. To address this question of whether it is possible to sleep “too much,” we reanalyzed data from two relevant studies that included most or all of the conditions cited above. These studies documented increased total sleep time during both nocturnal and daytime (nap) sleep episodes compared to an individual’s self-selected sleep times at home; this sleep amount decreased over the days of the protocol

Methods

Results

Conclusion