Even if you don’t wear a smart watch or fitness bracelet to track your heart rate, you can often feel your heart rate fluctuate throughout the day. During your waking hours, the number of heartbeats per minute when you are just sitting quietly is called your resting heart rate. In most adults, the resting heart rate varies between 60 and 100 beats per minute.
Once you get up and move around, your heart rate increases. And exercise makes it even stronger. Even intense emotions – fear, anger, or surprise – can cause your heart rate to skyrocket. But what happens when you lie down to sleep? The answer differs depending on the phase of sleep: light sleep, deep sleep or REM sleep.
How does your heart rate change while you sleep?
“During sleep, the stimulation of your nervous system is reduced and most of the processes in your body slow down,” says Dr. Lawrence Epstein, associate physician in the Sleep and Circadian Disorders Division at Brigham and Women’s Hospital, affiliated with Harvard. .
About five minutes after you sleep, your heart rate gradually slows down to its resting rate when you enter what is called light sleep. Your body temperature drops and your muscles relax. People typically spend about half the night in light sleep. But in the next phase of deep sleep, your blood pressure drops, and your heart rate slows to about 20% to 30% below your resting heart rate.
When you dream, you enter the phase of sleep known as REM (also called dream sleep). “Your heart rate may vary a bit during REM sleep because it reflects the level of activity that is happening in your dream. If your dream is scary or involves an activity such as running, your heart rate increases as if you are awake, ”says Dr. Epstein.
Can you change your heart rate while resting?
If you run or do other moderate to vigorous physical activity regularly, you may reduce your resting heart rate. This is because exercise strengthens the heart muscle, allowing it to pump a greater volume of blood with each heartbeat. As a result, more oxygen is delivered to the muscles, so the heart does not need to beat as many times as it would in someone who is less fit.
As people get older, the resting heart rate stays roughly the same unless they take drugs that slow the heart rate, such as beta blockers or calcium channel blockers.
To find your resting heart rate, try taking your pulse when you wake up a few days a week for several weeks. With your index and middle fingers, press lightly on the opposite wrist, just below the fat pad of your thumb. Or press gently on the side of your neck, just below your jawline. Count the number of beats over a 30 second period. Double this number to get your heart rate in beats per minute. (Measuring just 15 seconds and multiplying by four is also pretty accurate.)
A resting heart rate that is too low (less than 50 beats per minute), or a rate of 100 or more, could be a sign of a problem and should prompt you to call your doctor.