We know that heart rate throughout the night is a sign-post of health and recovery. So we asked, "is it true that the more we sleep, the lower the average heart rate is throughout the night?”

The data shows that this is not necessarily the case, and that includes our weekly work schedules and weekend opportunity to sleep in.

For example, on average, we spend the most wake-time on Fridays, and as the graph shows, our average heart rates are higher on Friday nights. During the corresponding Saturday mornings, we tend to sleep in and our sleep durations end up longer, yet our heart rates throughout the night are higher.

One possible explanation is an increase in REM sleep when the heart rate is generally elevated. Of course, “lifestyle” (alcohol and larger / later meals) also contribute to elevated heart rates measured on Friday and Saturday nights.