To determine if bed and wake times can be determined from continuous ECG recordings in the elderly, PSG (polysomnogram), ECG channels were extracted and scanned on a Holter analyzer for N=56 participants (age 76±3) in the Sleep Heart Health Study who had 2 PSGs 5 years apart. Bed and wake times were determined from a combination of 5-min averagaed HR and HRV patterns and from HR tachograms of normal-to-normal intervals. Bed and wake times were also extracted from the PSGs. PSG-and HRV bed and wake times were compared via paired t-tests and correlation analysis. Correlations between PSG-and HRV-determined bed and wake times were ≤0.95. HRV-derived bed and wake times were slightly (4±7 min) earlier for and 5±11 min earlier the 2 PSGs, p≤0.001. Mean PSG and ECG-based wake times were closer (12±20s earlier, p=0.069 and 2±8 min later, p=0.049 for the 2 PSGs). Therefore, determination of bedtime and wake time patterns in large Holter cohorts without activity diaries is feasible.