Your nighttime resting heart rate curve is your heart’s personal signature. A lower resting heart rate (RHR) is a sign of quality recovery and health.
By looking at your resting heart rate (RHR) curve, you can also see the effects of late meals, evening workouts, alcohol, sickness, or being misaligned with your body’s ideal sleep window.
Resting Heart Rate During the Night
Nightly average RHR varies widely between individuals. It can range anywhere from 40 to 100 beats per minute (BPM) and still be considered normal. It can also change from day to day, depending on your hydration level, elevation, exercise, and body temperature. As with many of your body’s signals, it’s best to compare your RHR with your own baseline. Avoid comparisons to those around you.
When looking at your RHR curve, pay special attention to these three things:
- Your trend: Does your RHR go up, down, or stay level during the night?
- Your lowest point: When is your RHR lowest?
- Your end: Right before you wake up, does your RHR change?
With these questions in mind, here are three patterns you may recognize in the nocturnal heart rate curves you can see with Oura:
The Hammock: Relaxed in Bed and Ready to Rise
The hammock curve shows an ideal heart rate journey. During your initial sleep stages, your body relaxes and your blood pressure and heart rate begin to drop.
In this scenario, your lowest RHR occurs near the midpoint of your sleep, when the amount of melatonin present reaches a peak. If you are perfectly in sync with the sun’s patterns, your body temperature drops to its lowest level around 4 a.m.
Your RHR may momentarily rise during REM sleep. This is normal and you can ignore these temporary spikes when looking for the hammock curve during your sleep.
As you wake in the morning, your heart rate begins to rise. The hammock curve is a sign that your body was relaxed during the night and is ready to rise after a quality night’s sleep.
The Downward Slope: Your Metabolism Working Overtime
The Downward Slope is a sign that your metabolism is working overtime. Did you have a late meal, a late workout, or a glass of wine before bed? If your RHR starts high and reaches its lowest point right before you wake up, you may start the day feeling groggy.
If you regularly see this downward slope, it may be wise to stop and reassess your evening routine. For example, if you normally work out late at night, exercising 1–2 hours earlier can result in positive changes.
The Hill: Too Exhausted for Bed
If your RHR increases right after you fall asleep, this could be a sign of exhaustion. Did you go to sleep on time? If it’s past your regular bedtime, you may start feeling the effects of increased melatonin–a hormone that aids sleep–and lower blood pressure. This communication from your body serves as a warning of sorts, reminding you to get to bed on time.
If you did go to sleep during your ideal bedtime window, it’s possible that your heart rate may be increasing at the start of the night for reasons you can’t control. For instance, your airways may have relaxed during sleep, causing you to snore, which raises your heart rate.
Tips for Improved Sleep
When you’re sound asleep, your body is wide awake. Welcome its feedback, listen closely to what it has to say, and take steps towards optimizing your sleep.
Use the following tips to help boost your sleep routine:
- Try to wake up at the same time seven days a week. (Yes, that includes weekends.)
- Time your meals mindfully; late meals may show up as the Downward Slope.
- If your sleep pattern is optimal (Hammock Curve), take notes. Think about what you did (or didn’t do) the previous day and continue to make similar choices.