The heartbeat secret: what it reveals about our health – from sleep and alcohol to fight or flight
aare you comfortable? If so, extend one hand so you are looking at your palm, and then use the index and middle fingers of your other hand to feel the pulse on the inside of your wrist. Count the beats for 60 seconds and that is your heart rate. Assuming you’re resting rather than exercising or stressed, it will probably be somewhere between 60 and 100 beats per minute. But what does it mean if it’s at the top or bottom of the range – or even beyond?
We have known about the connection between heart rate and health for thousands of years. Herophilus of Alexandria (325-255 BC), also known as the father of anatomy, designed a water clock to time the heartbeat, around the same time that Chinese physicians were using its strength and regularity to diagnose disease. A few centuries later, the Roman-Greek surgeon Galen stirred things up by watching the hearts of recently deceased gladiators take their last beat, then wrote: “Practice to begin with – and as long as it is practiced in moderation – makes the pulse powerfully large. , fast and frequent. Large amounts of exercise, beyond the capacity of the individual, make it small, weak, rapid and extremely frequent.” Since then, doctors and scientists have been working hard on different ways to track our heart rate and its variations. What do the measurements actually tell us?
Let’s go back to that resting heart rate figure of 60-100 bpm. “A healthy range can vary depending on factors such as age, gender, fitness level, and overall health,” says Dr. David Culpepper, a family medicine specialist at LifeMD. “Athletes and people who are very fit can have a resting heart rate of less than 60 beats per minute, while babies and young children can often have a heart rate above 100 beats per minute, which gradually decreases as they get older.”
If your heart rate is below 60 beats per minute, you may now be congratulating yourself on your athlete-level fitness. But take a swing. Bradycardia — a slower-than-normal heart rate — “can also be caused by problems with the heart’s electrical system, an underactive thyroid gland, or other medical conditions,” says Culpepper. “Also, some medications – especially those used to treat high blood pressure and certain heart conditions – can lower heart rate as a side effect.”
Your lifestyle can also affect your heart rate, usually by increasing it. Stimulants can cause dramatic changes. “Caffeine increases the effects of adrenaline on the heart, meaning excessive consumption of tea, coffee or energy drinks can cause a temporary increase in heart rate – although this effect may decrease over time as your tolerance increases,” says Dr .Elijah Behr. , a consultant cardiologist at the Mayo Clinic in London. “Nicotine in cigarettes can temporarily increase heart rate and contribute to chronic heart and circulatory problems with long-term use. Depending on the individual and the amount consumed, alcohol consumption may increase or decrease the heart rate.” In the longer term: too much Drink can damage the heart musclewhich affects heart rate and overall heart health.
Emotional states such as stress, anxiety, or excitement can cause short-term spikes in heart rate, and chronic stress can contribute to long-term irregularities. But if you’re not under any particular pressure, a racing heart is a cause for concern. “If it comes out of the blue, for no apparent reason, it may be due to an underlying heart condition and should be investigated,” says Behr. “Clearly the urgency is greater when the racing heart causes dizziness or blackout.”
What about exercise? As Galen noted, your heart rate will increase as you actually exercise because your heart is pumping blood to your muscles and lungs. a recent meta-analysis of research confirms that cardiovascular exercise (and yoga) can lower your resting heart rate over time – but that also appears to be the case heart health benefits from strength training, although the mechanism is less well understood. Even more relaxing forms of exercise, such as tai chi and qigong, can help.
You may have come across the ‘finite heart rate theory’, or the idea that there’s a limit to how many times our ticker can impact our lives, but it’s unlikely to be worth worrying about: Even if it were true that you only had about four billion beats to play with, the (relatively) small amount of time that your heart rate is elevated by exercise should be more than offset by this over time to lower.
You can also practice improve your heart rate recovery (HRR)., the speed at which things return to normal after you stop, by making your circulatory system and your heart itself more efficient. a recent overview of studies suggests that HRR is probably a good indicator of overall heart health (to be clear, faster recovery is better).
There’s another number that scientists are becoming increasingly excited about: heart rate variability (HRV). Although your heart rate itself represents an average — it’s the number of times your heart beats over a given period of time — HRV reflects the heart rate changing pace of those heartbeats, because even if there are sixty in a minute, they will not happen every second, every second. We’ve known about HRV for a while – Carl Ludwig’s kymograph made it possible to measure it in the 1840s (using a metal drum covered in smoked paper) – but it’s only with the influx of wearables like smartwatches and fitness trackers that most people people can measure it in a way that can be useful.
The variability itself is caused by the two competing branches of what is collectively known as your autonomic nervous system, consisting of the sympathetic, which regulates ‘fight or flight’ responses, and the parasympathetic, which regulates ‘rest and digest’ functions. The sympathetic system urges your heart to speed up, the parasympathetic system tells it to calm down, and the resulting fluctuations are a sort of shorthand for the health and adaptability of your overall nervous system. “Measuring our resting heart rate and HRV first thing in the morning or during the night can give us a useful indication of our body’s stress response,” says Dr. Marco Altini, an ultra-distance runner, scientist and specialist in heart rate training. . A higher number isn’t always better, he says: “It’s critical to determine your own optimal range and pay attention to when you go beyond it.”
If we are healthy and manage the various sources of stress we face – physical or psychological – our HRV will quickly return to normal after exercise. On the other hand, if something is still wrong and we experience more stress than we can handle, the next night or morning our heart rate will still be slightly elevated and our HRV depressed. If you’re planning on doing a big workout – say, a high-pace run or a tough gym session – this would be your cue to take it easy until you’re in better shape.
This ability to fine-tune when and how hard we train is one of the reasons for the popularity of devices like the Whoop band and Oura ring, which measure both heart rate and HRV 24 hours a day. But it’s not just about sports.
“We may start to see more clearly the negative effect of certain stressors – such as our alcohol intake – on our bodies,” says Altini. better choices for our health and the health of others.” Research shows this, for example hydration has a positive effect on both heart rate and HRV, while poor sleep quality has a negative effect. Simply being more aware of these effects can help you address them.
So if you want to be more aware of what’s going on in your body and how your lifestyle affects it, your heart rate and HRV can be useful tools. It has never been easier to measure them both. But perhaps Prof. Andrew Flatt, a specialist in HRV training, should have the final word: “Tracking is useful, insightful, educational and so on – but not necessary,” he says. “Ultimately, applying it correctly will lead you to most of the behaviors people should be doing anyway. You will realize that you need to exercise daily or be less sedentary, prioritize good sleep, eat well, quit smoking, limit alcohol, manage stress, nurture good relationships and get periodic rest have to budget. It’s a behavior change tool for health – but I wouldn’t tell anyone that needs to use it.”
A beginner’s guide to heart rate training
Many runners “struggle with the intensity”, in the words of British Athletics running coach Dr Beatrice Schaer. “They tend to run too hard on what should be their ‘easy’ runs, but don’t work hard enough on what should be their ‘harder’ runs.”
Heart rate training addresses this by splitting your run into different intensity levels, or “zones,” based on your maximum heart rate (MHR). Here’s your simple guide to getting started.
1 Calculate your max
Common advice is to calculate your MHR by plugging your age into a formula – simply subtracting it from 220, or calculating some more complex amounts – but this method has its problems (and also tends to misrepresent maximum heart rate in women). “If it can be done safely, the best way to determine an individual’s maximum heart rate is after high-intensity exercise,” says Altini. A classic example is a 5K run, where you cover the last mile as quickly as possible. Your heart rate at the finish should be close to your MHR (note: please do not do this if you have any health problems).
2 Train in the zone
Once the hard part is done, you can make at least some of your workouts easier. Each heart rate zone corresponds to a certain percentage of your top intensity. For example, if your MHR is 185, you can simply multiply that by 0.5 and 0.6 to find your zone 1 intensity. There are plenty of calculators that do this online, but many modern wearables will do it for you.
3 Accelerate (slow)
From here, simply keep your cardio efforts within the limits prescribed by the training plan you’re using: this typically involves heavy efforts in zones 1 and 2, building up to intervals or full workouts in zones 3 and 4. Weeks pass .