Monitoring Heart Rate During Slumber: An Interpretation of Those Readings
In this vibrant digital era, we can't help but be enamored with numbers, statistics, and gadgets that track various health indicators, including our heart rate. Generally, these figures reveal how hard our heart is pulsing to keep us ticking. But what exactly do these numbers signify, and how do they shift when we're active, asleep, or resting?
Let's dive in to find the answers.
First things first: your heart rate equals the number of heartbeats you experience per minute. And you guessed it - this number goes up and down depending on your activities, or lack thereof, plus a series of systems working in tandem. Your autonomic nervous system controls your resting heart rate predominantly.
This autonomic nervous system consists of two main players: the sympathetic nervous system (fight-or-flight) and the parasympathetic nervous system (calm-and-relaxed). The delicate balance between these opposing forces greatly impacts your heart rate.
As Dr. Michael Faulx, a cardiologist, puts it, "Your heart rate serves as a tell-tale sign of what's occurring in your body and mind at that instant. A faster-than-usual heart rate often reflects the dominance of the sympathetic nervous system, indicating that you're in some form of stress."
Speaking of resting heartrates, a healthy adult should aim for a range of around 60 to 100 beats per minute (bpm). But how does your heart rate during sleep paint the picture of you? After all, those numbers likely fall well below or above the 60-beats-per-minute threshold, especially when you're dreaming. Dr. Faulx illuminates the transformation of your heart rate in slumber.
How your heart rate alters during sleep
Your resting heartrate is naturally lower than your active heartrate. Similarly, your sleeping heart rate usually falls lower than your daytime resting heart rate since your heart essentially switches to autopilot during sleep.
"Generally speaking, your sleeping heart rate tends to run approximately 20% to 30% lower than your daytime resting heart rate," shares Dr. Faulx.
Keep in mind that your heart rate fluctuates as you navigate the stages of sleep.
"During non-REM sleep is when your heart rate and blood pressure generally decrease, particularly during deep sleep," explains Dr. Faulx. "You could think of it as a time when your heart has a chance to hibernate during the night and catch its breath so it doesn't beat too rapidly."
An average sleeping heart rate
"A healthy adult will typically run a heart rate of about 60 to 100 bpm during the day, with a normal heart rate during sleep being somewhere between 50 to 75 bpm," says Dr. Faulx.
However, children's perspectives are quite different, as adult heartrates tend to slow as we age.
"In children, resting heartrates are quicker and it depends on their age. A child's heartrate is often more than 100 bpm, and that is considered normal. Infants and toddlers can even reach rates above 130, and that's still considered normal," he elucidates.
What triggers an unusual sleeping heart rate?
Given the myriad factors at play, what constitutes an abnormal sleeping heartrate? Generally, any sleeping heart rate outside the spectrum of 40 to 100 bpm would appear unordinary, but focusing solely on the numbers for an assessment can potentially complicate matters.
Dr. Faulx clarifies, "What's normal for an individual can fluctuate based on factors like age, weight, genetics, physical activity, and other health conditions one may have. An adult's sleeping heart rate below 40 bpm or above 100 bpm during sleep could fall outside the normal range. However, whether that's something to be concerned about hinges on your own feelings and other medical conditions you may have."
Pregnancy
In pregnancy, stress levels heighten because your heart must supply enough blood not just for you, but for the placenta and the rapidly developing fetus as well.
"By the time you reach the third trimester, your heart needs to increase its total blood content and production by at least 50%. During pregnancy, we anticipateheart rates to ascend. So an elevated sleeping heart rate above 100 bpm and being pregnant, yet feeling well, should not raise alarm."
Stress and anxiety
When you're feeling overwhelmed, anxious, or under strain, your flight-or-fight reaction triggers your body to flood with stress hormones like adrenaline and cortisol.
"High anxiety levels will result in more of these stress hormones circulating in your bloodstream, leading to an increase in blood pressure and a swifter sleeping heart rate," Dr. Faulx explains. "By addressing your anxiety, you'll likely experience lower blood pressure, a calm heartrate, and overall improved health."
Physical fitness
When exerting yourself, your heart rate increases to accommodate the demands of your sympathetic nervous system and the autonomic need to sustain your breathing and blood flow throughout your body. But when at rest or asleep, the parasympathetic nervous system adeptly induces relaxation due to the strengthening of the vagus nerve.
"The vagus nerve is a nerve that begins in the brainstem and links to your entire body, specifically your heart, lungs, and gut," says Dr. Faulx. "People who are more physically fit will have slower heart rates because of the influence of the vagus nerve."
When the vagus nerve is engaged, it lowers your blood pressure and slows your heart rate, so when you push yourself, you essentially train the vagus nerve to intervene and decelerate your heartrate every time.
"For instance, well-conditioned athletes like marathon runners, triathletes - their vagal nerve tone is so potent that when they sleep, their heart rate may dip into the 30s or even lower," he continues. "As long as they're feeling fine and they're not experiencing symptoms during the day, we generally don't be concerned."
Poor sleep hygiene
Remember that sleep allows your heart to unwind and recuperate. However, if you don't reach the deep sleep stage, your resting heart rate will probably fall short of the lower end of the spectrum and have a higher rate than expected.
"With sleep apnea - when your breathing is frequently obstructed during the night - your mind and body are in a perpetual state of distress, and you won't cycle normally through the stages of sleep," notes Dr. Faulx. "This leaves you without a period during sleep where you're recovering. Your blood pressure rises, your heart rate rises, and these stressors may even linger into the following day."
Other conditions and sleep disorders that influence your sleeping heart rate include:
- Insomnia
- Restless legs syndrome
- REM sleep behavior disorder
- Delayed sleep phase syndrome
- Overactive bladder
- Nocturia
- Chronic pain
- Sleeping with too much caffeine or screen time close to bedtime
Dehydration
Water offers numerous health advantages, including sustaining life.
"If you're dehydrated, your heart doesn't get the chance to expand normally and prepare for each regular beat because the filling pressures are minimal," shares Dr. Faulx. "Dehydrated individuals typically exhibit a quicker resting heart rate and swifter sleeping heart rate."
Medications and other medical conditions
Certain medications, including beta-blockers for high blood pressure and stimulant medications for ADHD, can lower your heart rate. And various health conditions, such as:
- Atrial fibrillation
- Ventricular dysrhythmia
- Heart block
- Premature ventricular contractions
- Other heart conduction disorders
- Overactive or underactive thyroids
can all impact your sleeping heart rate.
When does a sleeping heart rate warrant concern?
"One reason people might opt to monitor their sleeping heart rate is if they feel unwell in some way," observes Dr. Faulx.
If you experience any of the following symptoms, it's advisable to book an appointment with a healthcare provider for evaluation:
- Irregular heartbeats, palpitations, or skipped heartbeats.
- Shortness of breath.
- Chest discomfort.
- Lightheadedness.
- Feeling faint.
- Numbness in your limbs.
"If you encounter any symptom that bothers you, these are all health issues pertaining to sleeping heart rates that fall outside the normal range that I encourage people to seek medical advice for," advises Dr. Faulx.
"If your heart rate is substantially over 100 bpm during sleep, it might warrant investigation even if you feel okay because it may reflect something going on like a sleep disorder. If you're recording heart rates in the 20s, that might warrant a dialogue with your doctor to ensure your numbers are accurate."
Managing an abnormal sleeping heart rate
In essence, physical activity, weight management, and good sleep hygiene can all contribute positively to your sleeping heart rate. Dr. Faulx recommends dedicating 30 minutes each day for moderate-intensity aerobic exercise, with a focus on spending as much time as possible within your target heart rate. To calculate your maximum predicted heart rate, simply deduct your age from 220. For cardiac fitness, your target heart rate during exercise should fall between 65% and 75% of this maximum.
Improve your sleep hygiene by planning more time to unwind, maintaining a cooler sleeping environment, and cutting down on nighttime snacks.
By enhancing these areas and addressing underlying conditions impacting your sleeping heart rate, you can create significant improvements in your overall health and the numbers associated with wellness.
- A healthy sleep pattern is essential for maintaining a balanced autonomic nervous system, as it helps reduce the heart rate and encourage relaxation, promoting better health-and-wellness and fitness-and-exercise.
- An irregular sleeping heart rate could be a sign of an underlying condition, such as sleep apnea, insomnia, restless legs syndrome, or REM sleep behavior disorder, which could negatively impact your environment, health, and overall well-being.
- Making lifestyle improvements, such as establishing good sleep hygiene, regular exercise, and proper hydration, can help lower a high sleeping heart rate, ensuring better sleep quality and overall health.
